diff --git a/src/main/claude/claude-api-retry-row.test.ts b/src/main/claude/claude-api-retry-row.test.ts
index a1c8da60cb7d..f36f54396fbf 100644
--- a/src/main/claude/claude-api-retry-row.test.ts
+++ b/src/main/claude/claude-api-retry-row.test.ts
@@ -54,7 +54,7 @@ async function statusRowsFor(frames: Record<string, unknown>[]) {
     now: () => 1_700_000_000_000,
     mintEpoch: () => 'epoch-1'
   })
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   deferred.bind({ journal, fence: 1, publish: vi.fn() })
   const translator = createClaudeJournalTranslator({ sink: deferred.sink, fallbackIdPrefix: '1' })
   for (const frame of frames) {
diff --git a/src/main/claude/claude-context-usage-restart.test.ts b/src/main/claude/claude-context-usage-restart.test.ts
index 4359799272e4..4c550fd62bf5 100644
--- a/src/main/claude/claude-context-usage-restart.test.ts
+++ b/src/main/claude/claude-context-usage-restart.test.ts
@@ -112,7 +112,7 @@ async function openJournal(): Promise<AgentSessionJournal> {
 
 /** One acquisition: a fresh sink and translator over the session's journal. */
 function acquire(journal: AgentSessionJournal) {
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   const translator = createClaudeJournalTranslator({ sink: deferred.sink, coalesceMs: 0 })
   deferred.bind({ journal, fence: 1, publish: () => {} })
   const answers: ((value: unknown) => void)[] = []
diff --git a/src/main/claude/claude-context-usage-unloaded-turn.test.ts b/src/main/claude/claude-context-usage-unloaded-turn.test.ts
index ed76a788c186..f7d1701c1d45 100644
--- a/src/main/claude/claude-context-usage-unloaded-turn.test.ts
+++ b/src/main/claude/claude-context-usage-unloaded-turn.test.ts
@@ -56,7 +56,7 @@ async function openJournal(): Promise<AgentSessionJournal> {
 }
 
 function translate(journal: AgentSessionJournal) {
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   const translator = createClaudeJournalTranslator({ sink: deferred.sink, coalesceMs: 0 })
   deferred.bind({ journal, fence: 1, publish: () => {} })
   const settle = async (): Promise<void> => {
diff --git a/src/main/claude/claude-stream-json-connection.test.ts b/src/main/claude/claude-stream-json-connection.test.ts
index 7d198c5a5de5..dae4fce8e336 100644
--- a/src/main/claude/claude-stream-json-connection.test.ts
+++ b/src/main/claude/claude-stream-json-connection.test.ts
@@ -385,7 +385,7 @@ describe('Claude stream-json connection', () => {
       now: () => 1_700_000_000_000,
       mintEpoch: () => 'epoch-1'
     })
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind({ journal, fence: 1, publish: vi.fn() })
     const translator = createClaudeJournalTranslator({ sink: deferred.sink })
     let settled = false
diff --git a/src/main/claude/claude-structured-command-dispatch.ts b/src/main/claude/claude-structured-command-dispatch.ts
index 3d03c18178c3..12b77bde4868 100644
--- a/src/main/claude/claude-structured-command-dispatch.ts
+++ b/src/main/claude/claude-structured-command-dispatch.ts
@@ -10,7 +10,8 @@ import type { ClaudeSession } from './claude-structured-session-state'
  *  makes the command's turn the open one before the send, and that same result ends it. */
 export async function dispatchClaudeCommand(
   session: ClaudeSession,
-  command: StructuredAgentSessionCommandRun
+  command: StructuredAgentSessionCommandRun,
+  sessionId: string
 ): Promise<AgentSessionCommandAdmission> {
   const sentUuid = randomUUID()
   session.translator?.beginCommand({
@@ -20,6 +21,7 @@ export async function dispatchClaudeCommand(
   })
   try {
     const admission = await dispatchClaudeTurn(session, {
+      sessionId,
       clientMessageId: command.clientMessageId,
       body: { kind: 'message', role: 'user', blocks: [{ type: 'text', text: '/compact' }] },
       ...(command.running.requestedAt === undefined
diff --git a/src/main/claude/claude-structured-dispatch-attachment-rejection.test.ts b/src/main/claude/claude-structured-dispatch-attachment-rejection.test.ts
index a23767c09681..89fc95876a37 100644
--- a/src/main/claude/claude-structured-dispatch-attachment-rejection.test.ts
+++ b/src/main/claude/claude-structured-dispatch-attachment-rejection.test.ts
@@ -158,6 +158,7 @@ describe('Claude structured dispatch attachment rejections', () => {
 
     await expect(
       dispatchClaudeTurn(session, {
+        sessionId: 'session-1',
         clientMessageId: 'client-1',
         body: userMessage([{ type: 'image-ref', path }])
       })
@@ -167,9 +168,10 @@ describe('Claude structured dispatch attachment rejections', () => {
       rejection: { kind: 'attachmentUnreadable' }
     })
     expect(session.connection.send).not.toHaveBeenCalled()
-    // The row drops the error, so the log is the only place left to find why.
+    // The row drops the error, so the trace is the only place left to find why.
     expect(warn).toHaveBeenCalledWith(
-      '[claude-dispatch] attachment could not be read:',
+      '[agent-session] claude-attachment-read failed',
+      { sessionId: 'session-1', providerSessionId: session.providerSessionId },
       expect.objectContaining({ code: 'ENOENT' })
     )
     warn.mockRestore()
diff --git a/src/main/claude/claude-structured-dispatch-content.ts b/src/main/claude/claude-structured-dispatch-content.ts
index 035b0a594926..bfd5f7089f5f 100644
--- a/src/main/claude/claude-structured-dispatch-content.ts
+++ b/src/main/claude/claude-structured-dispatch-content.ts
@@ -14,6 +14,7 @@ import {
 } from '../../shared/agent-session-failure-words'
 import { TUI_AGENT_DISPLAY_NAMES } from '../../shared/tui-agent-display-names'
 import { claudeRecord } from './claude-structured-item-translation'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 
 /** Orca refused the message's content, as opposed to failing to read an attachment. */
 export class ClaudeDispatchContentError extends Error {
@@ -47,12 +48,20 @@ export function claudeDispatchRejection(
 
 /** Why a message whose content could not be built was not sent: Orca's own refusal of it, or an
  *  attachment it could not read. Never the provider. */
-export function claudeDispatchContentRejection(error: unknown): AgentJournalDispatchRejection {
+export function claudeDispatchContentRejection(
+  error: unknown,
+  ids: { sessionId?: string; providerSessionId: string }
+): AgentJournalDispatchRejection {
   if (error instanceof ClaudeDispatchContentError) {
     return claudeDispatchRejection(error.failure)
   }
-  // The row says only that it could not be read; why belongs in the log.
-  console.warn('[claude-dispatch] attachment could not be read:', error)
+  // The row says only that it could not be read; why belongs in the trace.
+  traceAgentSessionError({
+    step: 'claude-attachment-read',
+    sessionId: ids.sessionId,
+    error,
+    detail: { providerSessionId: ids.providerSessionId }
+  })
   return claudeDispatchRejection(agentSessionFailureFact('attachmentUnreadable'))
 }
 
diff --git a/src/main/claude/claude-structured-dispatch.test.ts b/src/main/claude/claude-structured-dispatch.test.ts
index 92ae0253711a..4bd0daafbbbd 100644
--- a/src/main/claude/claude-structured-dispatch.test.ts
+++ b/src/main/claude/claude-structured-dispatch.test.ts
@@ -406,15 +406,16 @@ describe('Claude structured dispatch image limits', () => {
     const body = userMessage([{ type: 'text', text: 'retry me' }])
 
     await expect(
-      dispatchClaudeTurn(session, { clientMessageId: 'client-1', body })
+      dispatchClaudeTurn(session, { sessionId: 'session-1', clientMessageId: 'client-1', body })
     ).resolves.toEqual({
       state: 'rejected',
       reason: 'provider_write_failed',
       rejection: { kind: 'writeFailed' }
     })
-    // The row keeps only the marker; why the write failed goes to the log.
+    // The row keeps only the marker; why the write failed goes to the trace.
     expect(warn).toHaveBeenCalledWith(
-      '[claude-dispatch] message could not be handed to Claude:',
+      '[agent-session] claude-dispatch-write failed',
+      { sessionId: 'session-1', providerSessionId: session.providerSessionId },
       expect.objectContaining({ message: expect.stringContaining('broken pipe') })
     )
     warn.mockRestore()
diff --git a/src/main/claude/claude-structured-dispatch.ts b/src/main/claude/claude-structured-dispatch.ts
index c208cceccdbf..4ba20202f0e1 100644
--- a/src/main/claude/claude-structured-dispatch.ts
+++ b/src/main/claude/claude-structured-dispatch.ts
@@ -19,6 +19,7 @@ import {
 import { dispatchWriteOutcomeUnknownReason } from '../native-chat/agent-session-journal/journal-dispatch-doubt-reasons'
 import { DISPATCH_REJECTED_QUEUE_FULL } from '../../shared/structured-agent-session-dispatch-rejection'
 import { agentSessionFailureFact } from '../../shared/agent-session-failure'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 import type { AgentJournalDispatchRejection } from '../../shared/agent-session-failure-words'
 import {
   claudeUnwrittenUserMessageError,
@@ -71,15 +72,26 @@ export function retireClaudeDispatchWaiters(session: ClaudeSession): void {
   }
 }
 
-/** The row keeps only the marker released clients hide; why the write failed belongs in the log. */
-function claudeWriteFailureRejection(error: unknown): AgentJournalDispatchRejection {
-  console.warn('[claude-dispatch] message could not be handed to Claude:', error)
+/** The row keeps only the marker released clients hide; why the write failed belongs in the trace. */
+function claudeWriteFailureRejection(
+  session: ClaudeSession,
+  sessionId: string | undefined,
+  error: unknown
+): AgentJournalDispatchRejection {
+  traceAgentSessionError({
+    step: 'claude-dispatch-write',
+    sessionId,
+    error,
+    detail: { providerSessionId: session.providerSessionId }
+  })
   return claudeDispatchRejection(agentSessionFailureFact('writeFailed'))
 }
 
 export async function dispatchClaudeTurn(
   session: ClaudeSession,
   input: {
+    /** Orca's session, which a trace record is filed under. */
+    sessionId?: string
     clientMessageId?: string
     body: AgentJournalMessageItem
     requestedAt?: number
@@ -92,7 +104,13 @@ export async function dispatchClaudeTurn(
   try {
     content = await claudeDispatchMessageContent(input.body)
   } catch (error) {
-    return { state: 'rejected', ...claudeDispatchContentRejection(error) }
+    return {
+      state: 'rejected',
+      ...claudeDispatchContentRejection(error, {
+        sessionId: input.sessionId,
+        providerSessionId: session.providerSessionId
+      })
+    }
   }
   if (session.dispatchWaiters.length >= MAX_ACTIVE_DISPATCH_WAITERS) {
     return { state: 'rejected', ...claudeDispatchRejection(agentSessionFailureFact('queueFull')) }
@@ -145,7 +163,7 @@ export async function dispatchClaudeTurn(
       if (error instanceof AgentSessionPreDispatchError) {
         throw error
       }
-      return { state: 'rejected', ...claudeWriteFailureRejection(error) }
+      return { state: 'rejected', ...claudeWriteFailureRejection(session, input.sessionId, error) }
     }
     const waiter = replay.waiter
     if (waiter.settledUuid) {
@@ -163,7 +181,7 @@ export async function dispatchClaudeTurn(
       waiter.resolve(null)
       // The frame was never handed to the SDK's input pump, so this is not doubt:
       // the message provably did not happen, which is what `rejected` means.
-      return { state: 'rejected', ...claudeWriteFailureRejection(error) }
+      return { state: 'rejected', ...claudeWriteFailureRejection(session, input.sessionId, error) }
     }
     if (!waiter.retired) {
       retireWaiter(session, waiter)
diff --git a/src/main/claude/claude-structured-effort-reporting.test.ts b/src/main/claude/claude-structured-effort-reporting.test.ts
index 2c319c86ee72..dcee9def9add 100644
--- a/src/main/claude/claude-structured-effort-reporting.test.ts
+++ b/src/main/claude/claude-structured-effort-reporting.test.ts
@@ -244,7 +244,7 @@ describe('Claude effort against the model that must run it', () => {
     const { session } = sessionWith('high', calls, { model: 'sonnet', catalog: [SONNET] })
     session.options.set('effort', 'low')
 
-    await restoreClaudeStructuredSessionOptions(session, undefined)
+    await restoreClaudeStructuredSessionOptions(session, undefined, 'session-1')
 
     expect(session.options.get('effort')).toBe('low')
     expect(session.restoreSkippedOptions.has('effort')).toBe(false)
@@ -257,7 +257,7 @@ describe('Claude effort against the model that must run it', () => {
     session.options.set('model', 'haiku')
     session.options.set('effort', 'high')
 
-    await restoreClaudeStructuredSessionOptions(session, undefined)
+    await restoreClaudeStructuredSessionOptions(session, undefined, 'session-1')
 
     expect(session.options.has('effort')).toBe(false)
     expect(session.restoreSkippedOptions.has('effort')).toBe(true)
diff --git a/src/main/claude/claude-structured-history-window.ts b/src/main/claude/claude-structured-history-window.ts
index 00ae86920251..61294e67493f 100644
--- a/src/main/claude/claude-structured-history-window.ts
+++ b/src/main/claude/claude-structured-history-window.ts
@@ -17,6 +17,7 @@
 import { join } from 'node:path'
 import type { AgentSessionJournalIdentity } from '../../shared/agent-session-journal-types'
 import { resolveSessionFilePath } from '../native-chat/session-file-resolver'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 import type {
   ProviderHistoryItem,
   ProviderHistoryWindow
@@ -281,12 +282,8 @@ export async function readClaudeProviderHistoryWindow(
   } catch (error) {
     // Unreadable, unprovable, or a single record too large to frame: all of them
     // leave the boundary unvouched for, which is not the same as an empty window.
-    // Oversize is no longer among them, so only the log separates what is left.
-    console.warn('[claude-history-window] transcript unprovable; boundary inconsistent:', {
-      transcriptPath: input.transcriptPath,
-      sessionId: input.sessionId,
-      error
-    })
+    // Oversize is no longer among them, so only the trace separates what is left.
+    traceAgentSessionError({ step: 'claude-history-window', sessionId: input.sessionId, error })
     return INCONSISTENT
   }
 }
diff --git a/src/main/claude/claude-structured-journal-translation-background-tasks.test.ts b/src/main/claude/claude-structured-journal-translation-background-tasks.test.ts
index 312eb6d05a27..5880f7d9ba09 100644
--- a/src/main/claude/claude-structured-journal-translation-background-tasks.test.ts
+++ b/src/main/claude/claude-structured-journal-translation-background-tasks.test.ts
@@ -179,6 +179,7 @@ describe('claude journal translation — background task rows', () => {
       return appendItem(...args)
     })
     const deferred = createDeferredStructuredAgentSessionEventSink({
+      onFailure: () => {},
       watermarks: {
         pauseQueuedOperations: 1,
         maxQueuedOperations: 4,
@@ -252,7 +253,7 @@ describe('claude journal translation — background task rows', () => {
 
   it('coalesces an unbound overflow patch and aliased final notification', async () => {
     const persisted = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const translator = createClaudeJournalTranslator({
       sink: deferred.sink,
       fallbackIdPrefix: 'test'
@@ -292,7 +293,7 @@ describe('claude journal translation — background task rows', () => {
 
   it('reconciles an aliased notification after a parentless overflow patch was persisted', async () => {
     const persisted = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind(persistedTarget(persisted))
     const first = createClaudeJournalTranslator({ sink: deferred.sink, fallbackIdPrefix: 'first' })
     fillLiveTaskRows(first)
@@ -353,7 +354,7 @@ describe('claude journal translation — background task rows', () => {
 
   it('resolves a queued restart identity after the sink rebinds', async () => {
     const persisted = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind(persistedTarget(persisted))
 
     const first = createClaudeJournalTranslator({ sink: deferred.sink, fallbackIdPrefix: 'first' })
@@ -371,7 +372,7 @@ describe('claude journal translation — background task rows', () => {
     first.dispose()
     await deferred.drained()
 
-    const restarted = createDeferredStructuredAgentSessionEventSink()
+    const restarted = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const second = createClaudeJournalTranslator({
       sink: restarted.sink,
       fallbackIdPrefix: 'second'
@@ -397,7 +398,7 @@ describe('claude journal translation — background task rows', () => {
 
   it('keeps pending writes from distinct runs when a translator is recreated', async () => {
     const persisted = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
 
     const first = createClaudeJournalTranslator({ sink: deferred.sink, fallbackIdPrefix: 'first' })
     spawnToolCall(first, 'toolu-first')
diff --git a/src/main/claude/claude-structured-journal-translation.test.ts b/src/main/claude/claude-structured-journal-translation.test.ts
index 1b03881e471b..8ff7b87f3ec2 100644
--- a/src/main/claude/claude-structured-journal-translation.test.ts
+++ b/src/main/claude/claude-structured-journal-translation.test.ts
@@ -258,7 +258,7 @@ describe('Claude structured journal translation', () => {
       now: () => 1_700_000_000_000,
       mintEpoch: () => 'epoch-1'
     })
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind({ journal, fence: 1, publish: vi.fn() })
     let scheduled: (() => void) | null = null
     const translator = createClaudeJournalTranslator({
@@ -317,7 +317,7 @@ describe('Claude structured journal translation', () => {
       now: () => 1_700_000_000_000,
       mintEpoch: () => 'epoch-1'
     })
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind({ journal, fence: 1, publish: vi.fn() })
     const translator = createClaudeJournalTranslator({ sink: deferred.sink })
     const approval = prompt({
diff --git a/src/main/claude/claude-structured-model-preflight.test.ts b/src/main/claude/claude-structured-model-preflight.test.ts
index 930947e112db..31f148675687 100644
--- a/src/main/claude/claude-structured-model-preflight.test.ts
+++ b/src/main/claude/claude-structured-model-preflight.test.ts
@@ -63,7 +63,7 @@ describe('Claude model pre-flight against the catalog the CLI listed', () => {
     const { session, calls } = sessionWith([DEFAULT_ROW, SONNET])
     session.options.set('model', 'claude-opus-4-retired')
 
-    await restoreClaudeStructuredSessionOptions(session, undefined)
+    await restoreClaudeStructuredSessionOptions(session, undefined, 'session-1')
 
     expect(calls).toEqual(['list_models'])
     expect(session.options.has('model')).toBe(false)
@@ -123,7 +123,7 @@ describe('Claude model pre-flight against the catalog the CLI listed', () => {
     const { session, calls } = sessionWith([DEFAULT_ROW, SONNET])
     session.options.set('model', 'sonnet')
 
-    await restoreClaudeStructuredSessionOptions(session, undefined)
+    await restoreClaudeStructuredSessionOptions(session, undefined, 'session-1')
 
     expect(calls).toEqual(['list_models', 'set_model:sonnet'])
     expect(session.options.get('model')).toBe('sonnet')
diff --git a/src/main/claude/claude-structured-options-context-window.test.ts b/src/main/claude/claude-structured-options-context-window.test.ts
index 452009b36895..e9a07733a896 100644
--- a/src/main/claude/claude-structured-options-context-window.test.ts
+++ b/src/main/claude/claude-structured-options-context-window.test.ts
@@ -66,7 +66,7 @@ describe('the context ring after a session option write', () => {
     const s = ringSession()
     s.session.options.set('model', 'opusplan')
     s.session.options.set('permissionMode', 'plan')
-    await restoreClaudeStructuredSessionOptions(s.session, undefined)
+    await restoreClaudeStructuredSessionOptions(s.session, undefined, 'session-1')
     expect(s.setModel).toHaveBeenCalledWith('opusplan', { timeoutMs: undefined })
     expect(s.modelMayHaveChanged).not.toHaveBeenCalled()
   })
@@ -74,7 +74,7 @@ describe('the context ring after a session option write', () => {
   it('asks for the new window when a restore cannot put the stored model back', async () => {
     const s = ringSession([{ value: 'sonnet', displayName: 'Sonnet' }])
     s.session.options.set('model', 'retired-model')
-    await restoreClaudeStructuredSessionOptions(s.session, undefined)
+    await restoreClaudeStructuredSessionOptions(s.session, undefined, 'session-1')
     expect(s.session.restoreSkippedOptions).toEqual(new Set(['model']))
     expect(s.modelMayHaveChanged).toHaveBeenCalledTimes(1)
   })
@@ -82,7 +82,7 @@ describe('the context ring after a session option write', () => {
   it('sizes a new session from the model its restore applied', async () => {
     const s = ringSession([{ value: 'opus[1m]', displayName: 'Opus (1M)' }])
     s.session.options.set('model', 'opus[1m]')
-    await restoreClaudeStructuredSessionOptions(s.session, undefined)
+    await restoreClaudeStructuredSessionOptions(s.session, undefined, 'session-1')
     expect(s.respond('turn-a', 1_000)).toMatchObject({ windowTokens: 1_000_000, percentage: 10 })
   })
 
@@ -102,7 +102,7 @@ describe('the context ring after a session option write', () => {
 
     const skipped = ringSession([{ value: 'sonnet', displayName: 'Sonnet' }])
     skipped.session.options.set('model', 'retired-model[1m]')
-    await restoreClaudeStructuredSessionOptions(skipped.session, undefined)
+    await restoreClaudeStructuredSessionOptions(skipped.session, undefined, 'session-1')
     expect(skipped.respond('turn-a', 1_000)).toBeNull()
   })
 
diff --git a/src/main/claude/claude-structured-options.test.ts b/src/main/claude/claude-structured-options.test.ts
index a92149a2cddf..d52bc7b56c64 100644
--- a/src/main/claude/claude-structured-options.test.ts
+++ b/src/main/claude/claude-structured-options.test.ts
@@ -180,7 +180,7 @@ describe('Claude structured Fast mode', () => {
     const { session, applyFlagSettings } = fastModeSession(undefined)
     session.options.set('fastMode', 'false')
 
-    await restoreClaudeStructuredSessionOptions(session, undefined)
+    await restoreClaudeStructuredSessionOptions(session, undefined, 'session-1')
 
     expect(session.options.get('fastMode')).toBe('false')
     expect(session.restoreSkippedOptions.has('fastMode')).toBe(false)
@@ -467,9 +467,16 @@ describe('Claude structured option restore under the request deadline', () => {
       ['effort', 'high'],
       ['permissionMode', 'plan']
     ])
-    vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
 
-    await expect(restoreClaudeStructuredSessionOptions(session, 10)).resolves.toBeUndefined()
+    await expect(
+      restoreClaudeStructuredSessionOptions(session, 10, 'session-1')
+    ).resolves.toBeUndefined()
+    expect(warn).toHaveBeenCalledWith(
+      '[agent-session] claude-option-restore failed',
+      expect.objectContaining({ sessionId: 'session-1' }),
+      expect.any(ClaudeControlRequestTimeoutError)
+    )
 
     expect(Object.fromEntries(session.options)).toEqual({ model: 'sonnet', effort: 'high' })
     expect([...session.restoreSkippedOptions]).toEqual(['permissionMode'])
diff --git a/src/main/claude/claude-structured-options.ts b/src/main/claude/claude-structured-options.ts
index 2f0b7ac4b707..46f2a39ef029 100644
--- a/src/main/claude/claude-structured-options.ts
+++ b/src/main/claude/claude-structured-options.ts
@@ -1,6 +1,7 @@
 import type { EffortLevel, PermissionMode } from '@anthropic-ai/claude-agent-sdk'
 import { ClaudeControlRequestError } from './claude-stream-json-connection'
 import { ClaudeControlRequestTimeoutError } from './claude-agent-sdk-control-requests'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 import {
   AgentSessionOptionRejectedError,
   isAgentSessionOptionRejectedError
@@ -250,7 +251,8 @@ export async function setClaudeStructuredOption(
 
 export async function restoreClaudeStructuredSessionOptions(
   session: ClaudeSession,
-  timeoutMs: number | undefined
+  timeoutMs: number | undefined,
+  sessionId: string
 ): Promise<void> {
   // Any write that was already in flight belongs to the previous acquisition
   // state and must not repopulate this map after restore starts.
@@ -268,9 +270,12 @@ export async function restoreClaudeStructuredSessionOptions(
       // A write the CLI never answered must not fault a start that is otherwise fine. Silence is
       // not a refusal, so the choice stays wanted, unconfirmed, and the next start retries it.
       if (error instanceof ClaudeControlRequestTimeoutError) {
-        console.warn(
-          `[claude-structured] restore of ${key} for ${session.providerSessionId} was not answered in time; keeping it unconfirmed`
-        )
+        traceAgentSessionError({
+          step: 'claude-option-restore',
+          sessionId,
+          error,
+          detail: { option: key, providerSessionId: session.providerSessionId }
+        })
         session.options.set(key, value)
         session.confirmedOptions.delete(key)
         continue
diff --git a/src/main/claude/claude-structured-provider-fallback.test.ts b/src/main/claude/claude-structured-provider-fallback.test.ts
index a3a47c8bea8a..31a27e83e785 100644
--- a/src/main/claude/claude-structured-provider-fallback.test.ts
+++ b/src/main/claude/claude-structured-provider-fallback.test.ts
@@ -80,7 +80,7 @@ describe('Claude provider fallback', () => {
       now: () => 1_700_000_000_000,
       mintEpoch: () => 'epoch-1'
     })
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind({
       journal,
       fence: 1,
diff --git a/src/main/claude/claude-structured-resume-point.test.ts b/src/main/claude/claude-structured-resume-point.test.ts
index 862909a2cd66..552af80c82b7 100644
--- a/src/main/claude/claude-structured-resume-point.test.ts
+++ b/src/main/claude/claude-structured-resume-point.test.ts
@@ -135,8 +135,9 @@ describe('Claude resume point is the last completed turn on every exit path', ()
     await tick()
     expect(events.at(-1)).toMatchObject({ type: 'ended', cause: 'unexpected-exit' })
     expect(warn).toHaveBeenCalledWith(
-      '[claude-resume-point] exit cursor was not persisted:',
-      expect.objectContaining({ sessionId: 'session-1', error: expect.any(Error) })
+      '[agent-session] claude-exit-cursor-persist failed',
+      { sessionId: 'session-1' },
+      expect.any(Error)
     )
   })
 })
diff --git a/src/main/claude/claude-structured-resume-point.ts b/src/main/claude/claude-structured-resume-point.ts
index e8124f52d27d..d6ef69b4fa49 100644
--- a/src/main/claude/claude-structured-resume-point.ts
+++ b/src/main/claude/claude-structured-resume-point.ts
@@ -1,3 +1,4 @@
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 import type {
   ClaudeSession,
   ClaudeStructuredSessionAdapterDeps
@@ -6,7 +7,7 @@ import type {
 /**
  * Record a completed turn: its leaf becomes the one close and exit persist, and the durable point
  * advances in place so an owner that dies before its close path runs keeps it. Writes run one at a
- * time, and a failure is only logged: this is bookkeeping and must never fail the turn.
+ * time, and a failure is only reported: this is bookkeeping and must never fail the turn.
  */
 export function persistClaudeTurnResumePoint(
   sessionId: string,
@@ -35,10 +36,11 @@ export function persistClaudeTurnResumePoint(
         })
       )
       .catch((error: unknown) => {
-        console.warn('[claude-resume-point] turn-end resume point was not persisted:', {
+        traceAgentSessionError({
+          step: 'claude-resume-point-persist',
           sessionId,
-          leafUuid,
-          error
+          error,
+          detail: { leafUuid }
         })
         // Forget the failed leaf so the next turn end retries it even when the leaf has not moved.
         if (session.resumePointWrite === write) {
diff --git a/src/main/claude/claude-structured-session-acquisition.ts b/src/main/claude/claude-structured-session-acquisition.ts
index b4adbfccfa5c..cb7accbf27d1 100644
--- a/src/main/claude/claude-structured-session-acquisition.ts
+++ b/src/main/claude/claude-structured-session-acquisition.ts
@@ -275,6 +275,7 @@ export async function acquireClaudeSession({
     session.startup.settled = Promise.race([
       session.startup.settled,
       settleClaudeSessionStartup({
+        sessionId,
         session,
         facts: readClaudeStartupFacts({
           connection,
diff --git a/src/main/claude/claude-structured-session-adapter.ts b/src/main/claude/claude-structured-session-adapter.ts
index 64d3c67c2277..b68d87ab46bd 100644
--- a/src/main/claude/claude-structured-session-adapter.ts
+++ b/src/main/claude/claude-structured-session-adapter.ts
@@ -191,7 +191,7 @@ export class ClaudeStructuredSessionAdapter implements StructuredAgentSessionAda
     dispatchClaudeTurn(this.session(input.sessionId), input, input.beforeDispatch)
 
   compact: NonNullable<StructuredAgentSessionAdapter['compact']> = (input) =>
-    dispatchClaudeCommand(this.session(input.sessionId), input.command)
+    dispatchClaudeCommand(this.session(input.sessionId), input.command, input.sessionId)
 
   cancelTurn: StructuredAgentSessionAdapter['cancelTurn'] = (request) =>
     cancelClaudeStructuredTurn({
diff --git a/src/main/claude/claude-structured-session-exit-lifecycle.ts b/src/main/claude/claude-structured-session-exit-lifecycle.ts
index 854646490a8c..86a324891a7c 100644
--- a/src/main/claude/claude-structured-session-exit-lifecycle.ts
+++ b/src/main/claude/claude-structured-session-exit-lifecycle.ts
@@ -4,6 +4,7 @@ import {
   providerStartupFailureFact
 } from '../native-chat/agent-session-wire/structured-agent-session-failure-text'
 import { settledClaudeTurnEndLeaf } from './claude-structured-resume-point'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 import {
   claudeRootExitObserved,
   settleClaudeExitedSession
@@ -79,8 +80,8 @@ export function settleClaudeUnexpectedExit(
     // Persist the last completed turn before publishing the lifecycle
     // event that lets the host release and reacquire this exact child.
     await persistClaudeSessionHandle(sessionId, exit.session, deps).catch((error: unknown) => {
-      // Recovery still publishes: the record keeps its last durable point, and the loss is logged.
-      console.warn('[claude-resume-point] exit cursor was not persisted:', { sessionId, error })
+      // Recovery still publishes: the record keeps its last durable point, and the loss is reported.
+      traceAgentSessionError({ step: 'claude-exit-cursor-persist', sessionId, error })
     })
     if (exits.get(sessionId) !== exit) {
       settleClaudeExitedSession(exit.session)
diff --git a/src/main/claude/claude-structured-session-reading-control.test.ts b/src/main/claude/claude-structured-session-reading-control.test.ts
index d89bd1feb094..ca55129dec73 100644
--- a/src/main/claude/claude-structured-session-reading-control.test.ts
+++ b/src/main/claude/claude-structured-session-reading-control.test.ts
@@ -212,6 +212,7 @@ describe('Claude structured reading control', () => {
     const persisted = new Map<string, AgentJournalItemBody>()
     const target = persistedTarget(persisted)
     const deferred = createDeferredStructuredAgentSessionEventSink({
+      onFailure: () => {},
       watermarks: {
         pauseQueuedOperations: 1,
         maxQueuedOperations: 4,
diff --git a/src/main/claude/claude-structured-session-startup.ts b/src/main/claude/claude-structured-session-startup.ts
index ce14a64dd2cf..d48c7802c104 100644
--- a/src/main/claude/claude-structured-session-startup.ts
+++ b/src/main/claude/claude-structured-session-startup.ts
@@ -163,6 +163,7 @@ function claudeStartedReportedOptions(
 /** Applies startup facts to the published session and restores saved options; only then does the
  *  session take input. Any failure faults the session so the user sees why it never started. */
 export async function settleClaudeSessionStartup(input: {
+  sessionId: string
   session: ClaudeSession
   facts: Promise<ClaudeStartupFacts>
   isCurrent: () => boolean
@@ -185,7 +186,7 @@ export async function settleClaudeSessionStartup(input: {
       return
     }
     applyClaudeStartupFacts(session, facts)
-    await restoreClaudeStructuredSessionOptions(session, input.requestTimeoutMs)
+    await restoreClaudeStructuredSessionOptions(session, input.requestTimeoutMs, input.sessionId)
     if (!superseded()) {
       input.onStarted({
         // `list_models` is answered from this same initialize result, so nothing is re-read.
diff --git a/src/main/claude/claude-structured-turn-resume-point.test.ts b/src/main/claude/claude-structured-turn-resume-point.test.ts
index 4cb72eaa53a6..4b977ac31aaa 100644
--- a/src/main/claude/claude-structured-turn-resume-point.test.ts
+++ b/src/main/claude/claude-structured-turn-resume-point.test.ts
@@ -180,8 +180,9 @@ describe('Claude durable resume point at turn end', () => {
       events.filter((event) => event.type === 'message' && event.message.type === 'result')
     ).toHaveLength(2)
     expect(warn).toHaveBeenCalledWith(
-      '[claude-resume-point] turn-end resume point was not persisted:',
-      expect.objectContaining({ leafUuid: 'a2' })
+      '[agent-session] claude-resume-point-persist failed',
+      { sessionId: 'session-1', leafUuid: 'a2' },
+      expect.any(Error)
     )
     await expect(adapter.closeSession('session-1')).resolves.toBe(true)
     expect(persistedHandles).toEqual([expect.objectContaining({ leafUuid: 'a2' })])
diff --git a/src/main/claude/claude-subagent-resume-after-restart.test.ts b/src/main/claude/claude-subagent-resume-after-restart.test.ts
index ef6c067db9ea..72c8c812c95d 100644
--- a/src/main/claude/claude-subagent-resume-after-restart.test.ts
+++ b/src/main/claude/claude-subagent-resume-after-restart.test.ts
@@ -137,7 +137,7 @@ async function openJournal(): Promise<AgentSessionJournal> {
 
 /** One provider process: a fresh sink and translator over the session's journal. */
 function acquire(journal: AgentSessionJournal) {
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   const translator = createClaudeJournalTranslator({ sink: deferred.sink, coalesceMs: 0 })
   deferred.bind({ journal, fence: 1, publish: () => {} })
   const settle = async (): Promise<void> => {
@@ -190,7 +190,7 @@ const rosterIds = (journal: AgentSessionJournal): Set<string> =>
 /** An older build re-rostered a resumed child in the later turn's row, so two rows list it. */
 async function journalAnOlderBuildListedTwice(): Promise<AgentSessionJournal> {
   const journal = await openJournal()
-  const older = createDeferredStructuredAgentSessionEventSink()
+  const older = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   older.bind({ journal, fence: 1, publish: () => {} })
   const listed = (id: string, state: NativeChatSubagentEntry['state']) => ({
     id,
diff --git a/src/main/claude/claude-subagent-roster.test.ts b/src/main/claude/claude-subagent-roster.test.ts
index 34ff506ee037..508c94543287 100644
--- a/src/main/claude/claude-subagent-roster.test.ts
+++ b/src/main/claude/claude-subagent-roster.test.ts
@@ -462,7 +462,7 @@ describe('ClaudeSubagentRoster — through the real sink queue', () => {
       },
       appendTombstone: async () => ({ epoch: 'e', sequence: 0 })
     } as unknown as AgentSessionJournal
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind({
       journal,
       fence: 1,
diff --git a/src/main/codex/codex-structured-journal-goal-resume.test.ts b/src/main/codex/codex-structured-journal-goal-resume.test.ts
index 6df0ba015757..d398382c5873 100644
--- a/src/main/codex/codex-structured-journal-goal-resume.test.ts
+++ b/src/main/codex/codex-structured-journal-goal-resume.test.ts
@@ -34,7 +34,7 @@ function goalFrame(goal: Record<string, unknown> = {}): Record<string, unknown>
 }
 
 function goalJournal(
-  options: Parameters<typeof createDeferredStructuredAgentSessionEventSink>[0] = {}
+  options: Partial<Parameters<typeof createDeferredStructuredAgentSessionEventSink>[0]> = {}
 ) {
   let rowSequence = 0
   let publishes = 0
@@ -43,7 +43,10 @@ function goalJournal(
   let visitedItems = 0
   const rows = new Map<string, AgentJournalRenderItem>()
   const writes: string[] = []
-  const deferred = createDeferredStructuredAgentSessionEventSink(options)
+  const deferred = createDeferredStructuredAgentSessionEventSink({
+    onFailure: () => {},
+    ...options
+  })
   // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: a fake journal exposing only the members the goal translator and deferred sink call.
   const journal = {
     get epoch() {
diff --git a/src/main/codex/codex-structured-journal-goal-revision.test.ts b/src/main/codex/codex-structured-journal-goal-revision.test.ts
index 4f8276005770..c1f0a2457086 100644
--- a/src/main/codex/codex-structured-journal-goal-revision.test.ts
+++ b/src/main/codex/codex-structured-journal-goal-revision.test.ts
@@ -56,7 +56,7 @@ function goalFrame(goal: Record<string, unknown> = {}) {
 /** The host's own sink bound to a real journal. Its publish is what a subscriber
  *  receives: the page after the cursor it had caught up to. */
 function journalSink(journal: AgentSessionJournal) {
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   const published: AgentSessionHistoryPage[] = []
   let subscriberCursor: AgentJournalCursor | null = null
   deferred.bind({
diff --git a/src/main/codex/codex-structured-journal-subagent-readers.test.ts b/src/main/codex/codex-structured-journal-subagent-readers.test.ts
index 69e28d67ec4b..24cb698506b1 100644
--- a/src/main/codex/codex-structured-journal-subagent-readers.test.ts
+++ b/src/main/codex/codex-structured-journal-subagent-readers.test.ts
@@ -51,7 +51,7 @@ async function openJournal(root: string): Promise<AgentSessionJournal> {
 async function session() {
   const root = await mkdtemp(join(tmpdir(), 'orca-codex-children-'))
   let journal = await openJournal(root)
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   deferred.bind({ journal, fence: 1, publish: () => {} })
   cleanups.push(async () => {
     deferred.close()
diff --git a/src/main/codex/codex-structured-journal-translation-settlement.test.ts b/src/main/codex/codex-structured-journal-translation-settlement.test.ts
index 344d99e03b4d..bbf1d43985bb 100644
--- a/src/main/codex/codex-structured-journal-translation-settlement.test.ts
+++ b/src/main/codex/codex-structured-journal-translation-settlement.test.ts
@@ -129,6 +129,7 @@ function deferredTarget(
 
 function hardWatermarkDeferred() {
   return createDeferredStructuredAgentSessionEventSink({
+    onFailure: () => {},
     watermarks: {
       pauseQueuedBytes: 1,
       maxQueuedBytes: 1,
diff --git a/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts b/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts
index f9714bbe0625..aae886444fdb 100644
--- a/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts
+++ b/src/main/codex/codex-structured-journal-translation-turn-lifecycle.test.ts
@@ -223,7 +223,7 @@ describe('codex turn lifecycle rows', () => {
       now: () => 9_000,
       stateDirectory: join(root, SESSION_ID)
     })
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const translator = createCodexJournalTranslator({
       sink: deferred.sink,
       sessionId: SESSION_ID,
diff --git a/src/main/codex/codex-structured-journal-translation.test.ts b/src/main/codex/codex-structured-journal-translation.test.ts
index 676d9054ed70..efb079284bdc 100644
--- a/src/main/codex/codex-structured-journal-translation.test.ts
+++ b/src/main/codex/codex-structured-journal-translation.test.ts
@@ -127,6 +127,7 @@ function deferredTarget(
 
 function hardWatermarkDeferred() {
   return createDeferredStructuredAgentSessionEventSink({
+    onFailure: () => {},
     watermarks: {
       pauseQueuedBytes: 1,
       maxQueuedBytes: 1,
@@ -713,6 +714,7 @@ describe('codex journal translation', () => {
     const publishes: string[] = []
     const readingControl = { pauseReading: vi.fn(), resumeReading: vi.fn() }
     const deferred = createDeferredStructuredAgentSessionEventSink({
+      onFailure: () => {},
       watermarks: {
         pauseQueuedBytes: 1,
         maxQueuedBytes: 1,
diff --git a/src/main/codex/codex-structured-journal-turn-settles-once-journal.test.ts b/src/main/codex/codex-structured-journal-turn-settles-once-journal.test.ts
index 7011cfa0302f..ba03c8abd3a1 100644
--- a/src/main/codex/codex-structured-journal-turn-settles-once-journal.test.ts
+++ b/src/main/codex/codex-structured-journal-turn-settles-once-journal.test.ts
@@ -39,7 +39,7 @@ async function session() {
     stateDirectory: root,
     now: () => 1_000
   })
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   deferred.bind({ journal, fence: 1, publish: () => {} })
   cleanups.push(async () => {
     deferred.close()
diff --git a/src/main/native-chat/agent-session-journal/journal-database.ts b/src/main/native-chat/agent-session-journal/journal-database.ts
index 2c01a653af38..480692a5bedd 100644
--- a/src/main/native-chat/agent-session-journal/journal-database.ts
+++ b/src/main/native-chat/agent-session-journal/journal-database.ts
@@ -9,6 +9,7 @@ import { hardenSqliteDatabaseFiles } from '../../sqlite/harden-database-files'
 import { createJournalTablesSql, JOURNAL_DB_SCHEMA_VERSION } from './journal-database-schema'
 import { JournalUnreleasedSchemaError } from './journal-open-failure'
 import { ensureQueuedMessagesTable } from './queued-message-schema'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export const JOURNAL_BUSY_TIMEOUT_MS = 5000
 /** Bounds the WAL a checkpoint leaves behind; SQLite truncates it back to this after a reset. */
@@ -120,10 +121,7 @@ export function runJournalTransaction<T>(
       try {
         db.exec('ROLLBACK')
       } catch (rollbackError) {
-        console.warn(
-          '[agent-session-journal] rolling back a failed transaction failed',
-          rollbackError
-        )
+        traceAgentSessionError({ step: 'journal-rollback', error: rollbackError })
         onStranded()
       }
     }
diff --git a/src/main/native-chat/agent-session-journal/journal-open-failure.ts b/src/main/native-chat/agent-session-journal/journal-open-failure.ts
index 5e014c279cb1..b8ee7a2041f0 100644
--- a/src/main/native-chat/agent-session-journal/journal-open-failure.ts
+++ b/src/main/native-chat/agent-session-journal/journal-open-failure.ts
@@ -13,6 +13,7 @@ import {
 } from '../../../shared/agent-session-wire-refusals'
 import { isSqliteCorruption } from '../../sqlite/sqlite-read-failure'
 import { AgentSessionJournalError } from './journal-write-guards'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 type JournalRefusalReason = AgentSessionRefusalReason<'agent_session_journal_unreadable'>
 
@@ -111,7 +112,7 @@ export function journalOpenReadRefusal(error: unknown): AgentSessionRefusalError
   if (isAgentSessionRefusalError(error)) {
     return error
   }
-  return unreadableRefusal(error, journalRefusalReason(error), true)
+  return unreadableRefusal(error, journalRefusalReason(error), { log: true })
 }
 
 const MAX_LOGGED_SESSIONS = 256
@@ -134,7 +135,7 @@ export function createJournalOpenReadRefusals() {
       if (!repeat && (logged.has(sessionId) || logged.size < MAX_LOGGED_SESSIONS)) {
         logged.set(sessionId, failure)
       }
-      return unreadableRefusal(error, reason, !repeat)
+      return unreadableRefusal(error, reason, { log: !repeat, sessionId })
     },
     /** The session opened or closed: its next failure is news. */
     forget: (sessionId: string): void => {
@@ -146,10 +147,15 @@ export function createJournalOpenReadRefusals() {
 function unreadableRefusal(
   error: unknown,
   reason: JournalRefusalReason,
-  log: boolean
+  report: { log: boolean; sessionId?: string }
 ): AgentSessionRefusalError {
-  if (log) {
-    console.warn('[agent-session] opening the conversation for a read failed:', error)
+  if (report.log) {
+    traceAgentSessionError({
+      step: 'journal-open-read',
+      ...(report.sessionId === undefined ? {} : { sessionId: report.sessionId }),
+      error,
+      detail: { reason }
+    })
   }
   const code = 'agent_session_journal_unreadable'
   return new AgentSessionRefusalError(refuse(code, { reason }, code), { cause: error })
diff --git a/src/main/native-chat/agent-session-journal/journal-per-session-import.test.ts b/src/main/native-chat/agent-session-journal/journal-per-session-import.test.ts
index ea28ba4ef838..131457c94684 100644
--- a/src/main/native-chat/agent-session-journal/journal-per-session-import.test.ts
+++ b/src/main/native-chat/agent-session-journal/journal-per-session-import.test.ts
@@ -380,7 +380,7 @@ describe('importing a per-chat journal', () => {
     const { epoch, rows } = await historyRows()
     await writeLegacyJournal(epoch, rows)
     const database = openTestJournalHostDatabase(root)
-    const errors = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    const warnings = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
     const input = {
       database,
       identity: IDENTITY,
@@ -402,7 +402,12 @@ describe('importing a per-chat journal', () => {
     ).toMatchObject({
       total: 0
     })
-    expect(errors).toHaveBeenCalledOnce()
+    // Refused on every open, logged once.
+    expect(
+      warnings.mock.calls.filter(
+        ([line]) => line === '[agent-session] legacy-journal-import failed'
+      )
+    ).toHaveLength(1)
     // A copy that reads back whole then imports it, over what the refused ones left.
     const journal = await openChat()
     expect(readTestJournalRows(database.db, IDENTITY.sessionId, epoch)).toEqual(rows)
@@ -416,7 +421,7 @@ describe('importing a per-chat journal', () => {
     expect(rows.filter((row) => row.rowJson.includes('On it.'))).toHaveLength(1)
     await writeLegacyJournal(epoch, rows)
     const database = openTestJournalHostDatabase(root)
-    const errors = vi.spyOn(console, 'error').mockImplementation(() => undefined)
+    const warnings = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
     const input = {
       database,
       identity: IDENTITY,
@@ -431,7 +436,12 @@ describe('importing a per-chat journal', () => {
 
     expect((await readFile(legacyJournalDatabaseFile(legacyDir()))).equals(before)).toBe(true)
     expect(readJournalSessionEpoch(database.db, IDENTITY.sessionId)).toBeNull()
-    expect(errors).toHaveBeenCalledOnce()
+    // Refused on every open, logged once.
+    expect(
+      warnings.mock.calls.filter(
+        ([line]) => line === '[agent-session] legacy-journal-import failed'
+      )
+    ).toHaveLength(1)
   })
 
   // T-R2B1: the copy committed and only the delete failed (a crash between them is the same). Rows appended since, a restart, and a
diff --git a/src/main/native-chat/agent-session-journal/journal-per-session-import.ts b/src/main/native-chat/agent-session-journal/journal-per-session-import.ts
index 5f85fdded437..9ac2c52b227a 100644
--- a/src/main/native-chat/agent-session-journal/journal-per-session-import.ts
+++ b/src/main/native-chat/agent-session-journal/journal-per-session-import.ts
@@ -54,6 +54,7 @@ import {
   readJournalRowsAfter,
   readJournalSessionEpoch
 } from './journal-row-table'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 const INSERT_ROW =
   'INSERT INTO journal_rows (session_id, epoch, seq, ts, row_json) VALUES (?, ?, ?, ?, ?)'
@@ -130,7 +131,7 @@ async function importOnce(input: ImportInput): Promise<PerSessionJournalImportOu
     if (!published) {
       return 'absent'
     }
-    retireLegacyJournal(input.legacyDirectory, input.remove)
+    retireLegacyJournal(input.legacyDirectory, sessionId, input.remove)
     return 'already-imported'
   }
   if (plan?.kind === 'kept') {
@@ -138,7 +139,7 @@ async function importOnce(input: ImportInput): Promise<PerSessionJournalImportOu
     return 'kept'
   }
   // Also a file a crash left after its copy was recorded (`copied`): deleted now, not copied again.
-  retireLegacyJournal(input.legacyDirectory, input.remove)
+  retireLegacyJournal(input.legacyDirectory, sessionId, input.remove)
   if (plan?.kind === 'copied') {
     return 'already-imported'
   }
@@ -252,7 +253,7 @@ async function verifyCopiedJournal(
   )
   if (!loggedMismatches.has(`${sessionId}\n${want}\n${got}`)) {
     loggedMismatches.add(`${sessionId}\n${want}\n${got}`)
-    console.error(`[agent-session-journal] ${error.message}; ${input.legacyDirectory} is kept`)
+    traceAgentSessionError({ step: 'legacy-journal-import', sessionId, error })
   }
   throw journalOpenRefusalError(error)
 }
diff --git a/src/main/native-chat/agent-session-journal/journal-per-session-source.ts b/src/main/native-chat/agent-session-journal/journal-per-session-source.ts
index dc548e2f3dd0..7cb98b361a55 100644
--- a/src/main/native-chat/agent-session-journal/journal-per-session-source.ts
+++ b/src/main/native-chat/agent-session-journal/journal-per-session-source.ts
@@ -9,6 +9,7 @@ import { startJournalRowFold, type JournalLoad } from './journal-open'
 import { legacyJournalDatabaseFile } from './journal-paths'
 import type { PerSessionJournalHead } from './journal-per-session-reimport'
 import { pendingJournalRepairSequence } from './journal-repair-marker'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** The newest per-chat file shape any build wrote. */
 const LEGACY_JOURNAL_SCHEMA_VERSION = 2
@@ -123,6 +124,7 @@ export async function foldLegacyJournal(
  */
 export function retireLegacyJournal(
   legacyDirectory: string,
+  sessionId: string,
   remove: (path: string) => void = (path) => rmSync(path, { force: true })
 ): void {
   const file = legacyJournalDatabaseFile(legacyDirectory)
@@ -133,7 +135,7 @@ export function retireLegacyJournal(
       remove(path)
     }
   } catch (error) {
-    console.warn(`[agent-session-journal] deleting imported ${legacyDirectory} failed`, error)
+    traceAgentSessionError({ step: 'legacy-journal-retire', sessionId, error })
     return
   }
   try {
diff --git a/src/main/native-chat/agent-session-journal/journal-queued-messages.ts b/src/main/native-chat/agent-session-journal/journal-queued-messages.ts
index 96b45c9d17cb..325e56efce91 100644
--- a/src/main/native-chat/agent-session-journal/journal-queued-messages.ts
+++ b/src/main/native-chat/agent-session-journal/journal-queued-messages.ts
@@ -43,6 +43,7 @@ import {
   settleQueuedMessagesForRow
 } from './queued-message-settlement'
 import { AgentSessionJournalError, assertJournalWritable } from './journal-write-guards'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** Tombstones must outlive the window in which their operation id could still be admitted as new. */
 export const QUEUED_MESSAGE_REPLAY_WINDOW_MS =
@@ -305,12 +306,9 @@ export class JournalQueuedMessages {
   /** Bookkeeping at open: a failure is reported and retried at the next open,
    *  never allowed to fail opening the chat. */
   repairAndPruneAtOpen(): Promise<void> {
-    return this.repairAndPrune().catch((error: unknown) => {
-      console.warn('[journal-open] queued-message repair skipped:', {
-        sessionId: this.deps.sessionId,
-        error: error instanceof Error ? error.message : String(error)
-      })
-    })
+    return this.repairAndPrune().catch((error: unknown) =>
+      traceAgentSessionError({ step: 'queued-repair', sessionId: this.deps.sessionId, error })
+    )
   }
 
   /**
diff --git a/src/main/native-chat/agent-session-journal/journal-restart-reconciliation.ts b/src/main/native-chat/agent-session-journal/journal-restart-reconciliation.ts
index f1484bf5da8a..39ad16ae8a8d 100644
--- a/src/main/native-chat/agent-session-journal/journal-restart-reconciliation.ts
+++ b/src/main/native-chat/agent-session-journal/journal-restart-reconciliation.ts
@@ -23,6 +23,7 @@ import {
 import { isQueuedAgentJournalSubmission } from '../../../shared/agent-session-queued-submission'
 import type { AgentSessionJournal } from './journal-store'
 import { reconcileSubmissions, type ProviderHistoryWindow } from './journal-submission-reconciler'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /**
  * Only a text-only body can be compared against provider content. A submission
@@ -101,10 +102,11 @@ export async function reconcileJournalSubmissionsAgainstHistory(input: {
   })) {
     if (outcome.outcome === 'unknown') {
       // Narrowing failed: the submission stays unconfirmed, so record why.
-      console.warn('[journal-reconcile] submission left unconfirmed:', {
-        clientMessageId: outcome.clientMessageId,
-        reason: outcome.reason,
-        fence: input.fence
+      traceAgentSessionError({
+        step: 'restart-reconciliation',
+        sessionId: input.journal.snapshot().sessionId,
+        error: `submission left unconfirmed: ${outcome.reason}`,
+        detail: { clientMessageId: outcome.clientMessageId, fence: input.fence }
       })
       continue
     }
diff --git a/src/main/native-chat/agent-session-journal/journal-row-writer.ts b/src/main/native-chat/agent-session-journal/journal-row-writer.ts
index a29585580ebe..9dc4d704ec3e 100644
--- a/src/main/native-chat/agent-session-journal/journal-row-writer.ts
+++ b/src/main/native-chat/agent-session-journal/journal-row-writer.ts
@@ -4,6 +4,7 @@ import type { JournalHostDatabase } from './journal-host-database'
 import type { AgentJournalCursor } from '../../../shared/agent-session-journal-types'
 import type { JournalRow } from './journal-row-schema'
 import { assertJournalFence, assertJournalWritable } from './journal-write-guards'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** Runs between BEGIN IMMEDIATE and COMMIT, on the SAME connection as the row
  *  insert; a throw rolls the whole append back. Synchronous by construction so
@@ -83,10 +84,11 @@ export class JournalRowWriter {
       this.deps.rolledBack?.()
       // The draft store re-derives what this missed from the committed rows: at open, and in
       // the drain step before a draft sends.
-      console.warn('[journal-append] row bookkeeping skipped:', {
+      traceAgentSessionError({
+        step: 'journal-row-bookkeeping',
         sessionId: this.deps.sessionId,
-        kind: row.kind,
-        error: error instanceof Error ? error.message : String(error)
+        error,
+        detail: { kind: row.kind }
       })
     }
   }
diff --git a/src/main/native-chat/agent-session-journal/queued-message-bookkeeping-failure.test.ts b/src/main/native-chat/agent-session-journal/queued-message-bookkeeping-failure.test.ts
index 638a62bdf02a..b55eeae7c902 100644
--- a/src/main/native-chat/agent-session-journal/queued-message-bookkeeping-failure.test.ts
+++ b/src/main/native-chat/agent-session-journal/queued-message-bookkeeping-failure.test.ts
@@ -107,8 +107,9 @@ describe('draft bookkeeping inside a journal append', () => {
     expect(journal.submission('sub-draft-1')?.dispatchState).toBe('rejected')
     expect(journal.queuedMessages.get('draft-1')?.state).toBe('dispatched')
     expect(warn).toHaveBeenCalledWith(
-      '[journal-append] row bookkeeping skipped:',
-      expect.objectContaining({ kind: 'dispatch' })
+      '[agent-session] journal-row-bookkeeping failed',
+      expect.objectContaining({ kind: 'dispatch' }),
+      expect.any(Error)
     )
     await journal.close()
     journal = await open()
diff --git a/src/main/native-chat/agent-session-journal/queued-message-store.test.ts b/src/main/native-chat/agent-session-journal/queued-message-store.test.ts
index 0e42a22be4d9..0a6494c05b08 100644
--- a/src/main/native-chat/agent-session-journal/queued-message-store.test.ts
+++ b/src/main/native-chat/agent-session-journal/queued-message-store.test.ts
@@ -509,8 +509,9 @@ describe('open-time repair and retention', () => {
     try {
       const journal = await open()
       expect(warn).toHaveBeenCalledWith(
-        '[journal-open] queued-message repair skipped:',
-        expect.objectContaining({ error: 'SQLITE_FULL' })
+        '[agent-session] queued-repair failed',
+        expect.anything(),
+        expect.objectContaining({ message: 'SQLITE_FULL' })
       )
       await queueDraft(journal, 'draft-1')
       expect(journal.queuedMessages.list()).toHaveLength(1)
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-agent-start.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-agent-start.ts
index a4c93fa00f88..f61107eb1b1d 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-agent-start.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-agent-start.ts
@@ -32,6 +32,7 @@ import {
   structuredAgentSessionResumeOperationId,
   structuredAgentSessionResumeParams
 } from './structured-agent-session-resume-eligibility'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** A resume answers with the attach's own refusal, verdict and all, so the asker can tell a lease
  *  someone else is settling from an owner that will not come back. */
@@ -79,7 +80,7 @@ export function ensureStructuredAgentSessionAgentForOperation(
 ): Promise<StructuredAgentSessionResumeOutcome> {
   return ensureStructuredAgentSessionAgent(context, sessionId).catch((error: unknown) => {
     // The error is Orca's own and goes to the log; the refusal says only that the start failed.
-    console.warn('[agent-session] starting the agent for an operation failed:', error)
+    traceAgentSessionError({ step: 'operation-agent-start', sessionId, error })
     return {
       ok: false,
       refusal: refuseUnclassified(
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts
index c469035c4689..09ff455b27d5 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-attach-flow.ts
@@ -44,6 +44,7 @@ import {
 } from '../../observability/agent-session-instrumentation'
 import type { ProviderHistoryWindow } from '../agent-session-journal/journal-submission-reconciler'
 import type { AgentSessionJournal } from '../agent-session-journal/journal-store'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type AttachFlowInput = {
   store: AgentSessionRecordStore
@@ -206,7 +207,7 @@ export async function performAttach(
     const thrown = failed ? error : preSpawnFailureInWords(error, wording)
     if (failed || thrown !== error) {
       // The answer carries only its sentence, so what failed is kept here.
-      console.warn('[agent-session] provider start failed:', error)
+      traceAgentSessionError({ step: 'provider-start', sessionId, error })
     }
     return (
       failed ?? {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-claude-root-exit.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-claude-root-exit.test.ts
index 7cfd7fe86234..c16ab2d587e5 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-claude-root-exit.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-claude-root-exit.test.ts
@@ -122,7 +122,7 @@ describe('Claude root-exit stop', () => {
       journalDatabase: openTestJournalHostDatabase(root),
       claimKeyId: 'key-1'
     }
-    const runtimeState = new StructuredAgentSessionHostRuntimeState(deps)
+    const runtimeState = new StructuredAgentSessionHostRuntimeState(deps, () => {})
 
     claude.connections[0]!.handlers.onExit?.(new Error('provider exited'))
     await expect(
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-close.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-close.test.ts
index bf3cd1f96a60..070b8cfe062f 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-close.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-close.test.ts
@@ -21,6 +21,11 @@ import {
 } from './structured-agent-session-rest-test-rig'
 import { StructuredAgentSessionIdleSweep } from './structured-agent-session-idle-sweep'
 import { hostTestAttachParams } from './structured-agent-session-host-test-data'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 let rig: RestTestRig
 
@@ -315,12 +320,11 @@ describe('the wind-down retry with a message queued (P2-31)', () => {
       hasOpenDispatch: () => false,
       stopAgent,
       stopStartingAgent: stopAgent,
-      closeConversation: vi.fn(async () => false),
-      onError: (_id, error) => {
-        throw error
-      }
+      closeConversation: vi.fn(async () => false)
     })
+    vi.mocked(traceAgentSessionError).mockClear()
     await sweep.tick()
+    expect(traceAgentSessionError).not.toHaveBeenCalled()
     expect(stopAgent).not.toHaveBeenCalled()
   })
 })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-lifetime.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-lifetime.ts
index f69129183b4a..e089aa10da67 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-lifetime.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-lifetime.ts
@@ -82,7 +82,6 @@ export function createStructuredAgentSessionConversationLifetime(host: {
         cause: 'host-stop'
       }),
     closeConversation,
-    onError: (sessionId, error) => deps().onEventSinkError?.({ sessionId, error }),
     ...deps().idleSweep
   })
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-open.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-open.ts
index ec938f17f13b..419c43c7b11e 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-open.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-conversation-open.ts
@@ -23,10 +23,8 @@ import type { AgentSessionRecordStore } from '../../runtime/agent-session-record
 import type { StructuredAgentSessionAdapter } from './structured-agent-session-adapter'
 import { settleStaleStructuredAgentSessionState } from './structured-agent-session-dead-generation-settlement'
 import { structuredAgentSessionFailureWordsContext } from './structured-agent-session-send-preparation'
-import type {
-  StructuredAgentSessionHostDeps,
-  StructuredAgentSessionHostSession
-} from './structured-agent-session-host-types'
+import type { StructuredAgentSessionHostSession } from './structured-agent-session-host-types'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type OpenedStructuredAgentSessionConversation = {
   session: StructuredAgentSessionHostSession
@@ -38,7 +36,6 @@ export type StructuredAgentSessionConversationOpenDeps = {
   store: Pick<AgentSessionRecordStore, 'getRecord'>
   adapter: Pick<StructuredAgentSessionAdapter, 'historyFilePath'>
   journalDatabase: JournalHostDatabase
-  onEventSinkError?: StructuredAgentSessionHostDeps['onEventSinkError']
 }
 
 /** An acquisition's own open: its reserve cleared the record's death evidence, so it settles
@@ -104,13 +101,13 @@ export async function openStructuredAgentSessionConversationJournal(
     // one is only doubt, which provider history decides under a won lease.
     await opened.journal.markPendingSubmissionsUnknown(fence)
   } catch (error) {
-    deps.onEventSinkError?.({ sessionId, error })
+    traceAgentSessionError({ step: 'journal-open-pending-doubt', sessionId, error })
   }
   // No child in this process writes to a journal nobody had open, so whatever it shows running
   // belongs to a generation that is gone, whatever the lease still claims. Settled before any
   // reader or child sees it.
   if (!options.acquisition) {
-    await settleGoneGeneration(deps, record, opened.journal)
+    await settleGoneGeneration(record, opened.journal)
   }
   return {
     session: { journal: opened.journal, params, child: null },
@@ -130,12 +127,11 @@ export async function resettleOpenStructuredAgentSessionConversation(
 ): Promise<void> {
   const record = deps.store.getRecord(sessionId)
   if (session && record?.lease.deathEvidence) {
-    await settleGoneGeneration(deps, record, session.journal)
+    await settleGoneGeneration(record, session.journal)
   }
 }
 
 async function settleGoneGeneration(
-  deps: Pick<StructuredAgentSessionConversationOpenDeps, 'onEventSinkError'>,
   record: AgentSessionRecord,
   journal: AgentSessionJournal
 ): Promise<void> {
@@ -150,7 +146,11 @@ async function settleGoneGeneration(
     })
   } catch (error) {
     // Best effort: the next open or acquire re-derives it.
-    deps.onEventSinkError?.({ sessionId: record.sessionId, error })
+    traceAgentSessionError({
+      step: 'gone-generation-settlement',
+      sessionId: record.sessionId,
+      error
+    })
   }
 }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.test.ts
index 3557594b7513..ef787111ec43 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.test.ts
@@ -9,6 +9,11 @@ import { createTrackedJournalOpener } from '../agent-session-journal/journal-hos
 import { StructuredAgentSessionConversations } from './structured-agent-session-conversations'
 import type { StructuredAgentSessionHostSession } from './structured-agent-session-host-types'
 import { hostTestAttachParams } from './structured-agent-session-host-test-data'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const IDENTITY: AgentSessionJournalIdentity = {
   sessionId: 'session-1',
@@ -22,6 +27,7 @@ const journals = createTrackedJournalOpener()
 let root: string | null = null
 
 afterEach(async () => {
+  vi.mocked(traceAgentSessionError).mockClear()
   await journals.closeAll()
   if (root) {
     await rm(root, { recursive: true, force: true })
@@ -55,7 +61,6 @@ describe('a conversation delivers what its journal commits', () => {
     const deliver = vi.fn()
     const conversations = new StructuredAgentSessionConversations({
       deliver,
-      onDeliveryError: vi.fn(),
       now: () => 0
     })
     const journal = await openJournal('a')
@@ -74,7 +79,6 @@ describe('a conversation delivers what its journal commits', () => {
     const sessions: Map<string, StructuredAgentSessionHostSession> =
       new StructuredAgentSessionConversations({
         deliver,
-        onDeliveryError: vi.fn(),
         now: () => 0
       })
     const journal = await openJournal('a')
@@ -89,7 +93,6 @@ describe('a conversation delivers what its journal commits', () => {
     const deliver = vi.fn()
     const conversations = new StructuredAgentSessionConversations({
       deliver,
-      onDeliveryError: vi.fn(),
       now: () => 0
     })
     const journal = await openJournal('a')
@@ -104,7 +107,6 @@ describe('a conversation delivers what its journal commits', () => {
     const deliver = vi.fn()
     const conversations = new StructuredAgentSessionConversations({
       deliver,
-      onDeliveryError: vi.fn(),
       now: () => 0
     })
     const replaced = await openJournal('a')
@@ -123,7 +125,6 @@ describe('a conversation delivers what its journal commits', () => {
     const deliver = vi.fn()
     const conversations = new StructuredAgentSessionConversations({
       deliver,
-      onDeliveryError: vi.fn(),
       now: () => 0
     })
     const journal = await openJournal('a')
@@ -137,12 +138,10 @@ describe('a conversation delivers what its journal commits', () => {
 
   it('reports a reader failure without failing the durable write', async () => {
     const failure = new Error('reader failed')
-    const onDeliveryError = vi.fn()
     const conversations = new StructuredAgentSessionConversations({
       deliver: () => {
         throw failure
       },
-      onDeliveryError,
       now: () => 0
     })
     const journal = await openJournal('a')
@@ -152,7 +151,11 @@ describe('a conversation delivers what its journal commits', () => {
       itemId: expect.any(String)
     })
 
-    expect(onDeliveryError).toHaveBeenCalledExactlyOnceWith('session-1', failure)
+    expect(traceAgentSessionError).toHaveBeenCalledExactlyOnceWith({
+      step: 'journal-delivery',
+      sessionId: 'session-1',
+      error: failure
+    })
     expect(journal.snapshot().items.map((item) => item.body)).toContainEqual({
       kind: 'status',
       text: 'durable'
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.ts
index c312d6013fd5..c28d8533998b 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-conversations.ts
@@ -1,5 +1,6 @@
 import type { AgentSessionJournal } from '../agent-session-journal/journal-store'
 import type { StructuredAgentSessionHostSession } from './structured-agent-session-host-types'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /**
  * The host's open conversations. A journal handle becomes a conversation's when it is set here,
@@ -21,7 +22,6 @@ export class StructuredAgentSessionConversations extends Map<
   constructor(
     private readonly delivery: {
       deliver: (sessionId: string, journal: AgentSessionJournal) => void
-      onDeliveryError: (sessionId: string, error: unknown) => void
       /** A conversation became held: state that waited on it (queued drafts) re-derives. */
       onOpened?: (sessionId: string) => void
       now: () => number
@@ -46,7 +46,7 @@ export class StructuredAgentSessionConversations extends Map<
         try {
           this.delivery.deliver(sessionId, journal)
         } catch (error) {
-          this.delivery.onDeliveryError(sessionId, error)
+          traceAgentSessionError({ step: 'journal-delivery', sessionId, error })
         }
       })
     })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-crash-turn-end.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-crash-turn-end.test.ts
index c7f8f09631a2..624c284b46eb 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-crash-turn-end.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-crash-turn-end.test.ts
@@ -41,6 +41,11 @@ import {
   HOST_TEST_LOCATION as LOCATION,
   HOST_TEST_SESSION as SESSION
 } from './structured-agent-session-host-test-data'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const PROVIDER_SESSION = 'provider-session-alpha-1'
 /** The tool call's row: the last thing the provider wrote before the crash. */
@@ -406,11 +411,10 @@ describe('a turn a read reached before the reconcile proved its owner dead', ()
 
   it('stays unverifiable when the revision cannot be written, and a later open revises it', async () => {
     let now = RELAUNCHED_AT
-    const onEventSinkError = vi.fn()
+    vi.mocked(traceAgentSessionError).mockClear()
     openHost({
       probeOwner: async () => ({ outcome: 'pid-absent' }),
-      now: () => now,
-      onEventSinkError
+      now: () => now
     })
     await host.history({ sessionId: SESSION, direction: 'tail' })
     const { journal } = host.collaboratorsForTests().sessions.get(SESSION)!
@@ -419,7 +423,9 @@ describe('a turn a read reached before the reconcile proved its owner dead', ()
     await host.reconcileRestartLeases()
     await drainSession()
 
-    expect(onEventSinkError).toHaveBeenCalledOnce()
+    expect(traceAgentSessionError).toHaveBeenCalledExactlyOnceWith(
+      expect.objectContaining({ step: 'gone-generation-settlement', sessionId: SESSION })
+    )
     expect(await settledTurn()).toEqual(UNVERIFIABLE_TURN)
     // The proof is durable on the record, so the next open converges.
     now += STRUCTURED_AGENT_SESSION_IDLE_MS + 1
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.test.ts
index 6677a50b4470..b39790e6b2af 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.test.ts
@@ -100,7 +100,7 @@ describe('dead structured-session generation settlement', () => {
         verdict: { state: 'unverifiable' },
         showUnexpectedExitOutcome: false
       })
-    ).resolves.toBe(true)
+    ).resolves.toEqual({ ok: true })
 
     const snapshot = journal.snapshot()
     expect(snapshot.submissions).toEqual([
@@ -135,9 +135,9 @@ describe('dead structured-session generation settlement', () => {
       showUnexpectedExitOutcome: true
     }
 
-    await expect(settleStructuredAgentSessionDeadGeneration(input)).resolves.toBe(true)
+    await expect(settleStructuredAgentSessionDeadGeneration(input)).resolves.toEqual({ ok: true })
     const settledCursor = journal.cursor()
-    await expect(settleStructuredAgentSessionDeadGeneration(input)).resolves.toBe(true)
+    await expect(settleStructuredAgentSessionDeadGeneration(input)).resolves.toEqual({ ok: true })
 
     expect(journal.cursor()).toEqual(settledCursor)
     expect(
@@ -166,7 +166,7 @@ describe('dead structured-session generation settlement', () => {
           detail: providerDiagnostic('stack frame '.repeat(4_000), 'log')
         })
       })
-    ).resolves.toBe(true)
+    ).resolves.toEqual({ ok: true })
 
     const statuses = journal
       .snapshot()
@@ -258,7 +258,7 @@ describe('dead structured-session generation settlement', () => {
         verdict: { state: 'interrupted', completedAt: 1_000 },
         showUnexpectedExitOutcome: false
       })
-    ).resolves.toBe(true)
+    ).resolves.toEqual({ ok: true })
   })
 
   it('settles a live unknown submission even when no unfinished item remains', async () => {
@@ -285,7 +285,7 @@ describe('dead structured-session generation settlement', () => {
         verdict: { state: 'interrupted', completedAt: 1_000 },
         showUnexpectedExitOutcome: false
       })
-    ).resolves.toBe(true)
+    ).resolves.toEqual({ ok: true })
 
     expect(journal.submissions()).toEqual([
       expect.objectContaining({
@@ -463,7 +463,7 @@ describe('whether a dead generation interrupted anything', () => {
           1_000
         )
       })
-    ).resolves.toBe(true)
+    ).resolves.toEqual({ ok: true })
 
     const snapshot = journal.snapshot()
     expect(snapshot.items.some((item) => item.body.kind === 'status')).toBe(false)
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.ts
index 72caac40844d..b500f27cbf7f 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-dead-generation-settlement.ts
@@ -35,6 +35,7 @@ import {
   exitedRootTurnScope,
   runningRootTurnScope
 } from './structured-agent-session-exit-turn-scope'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** Bounds the exit reason the lease keeps as log evidence; a provider diagnostic is held to the
  *  same cap. */
@@ -102,6 +103,11 @@ export function unfinishedStructuredAgentSessionWorkWasInterrupted(
   return outcomeItems.some((item) => !isCleanlySettled(currentItems.get(item.itemId)))
 }
 
+/** A failed settlement carries its error so a caller that throws can name the cause. */
+export type StructuredAgentSessionDeadGenerationSettlement =
+  | { ok: true }
+  | { ok: false; error: unknown }
+
 export async function settleStructuredAgentSessionDeadGeneration(input: {
   journal: DeadGenerationJournal
   sessionId: string
@@ -117,13 +123,12 @@ export async function settleStructuredAgentSessionDeadGeneration(input: {
   /** The provider never finished starting: the start that failed, keyed by the child's
    *  generation. Its row is the one the delivery loop writes for the same start. */
   exitedDuringStartup?: { generation: string | null }
-  onError?: (sessionId: string, error: unknown) => void
-}): Promise<boolean> {
+}): Promise<StructuredAgentSessionDeadGenerationSettlement> {
   try {
     const hasUnfinishedWork = hasUnfinishedStructuredAgentSessionWork(input.journal)
     const showUnexpectedExitOutcome = input.showUnexpectedExitOutcome ?? hasUnfinishedWork
     if (!showUnexpectedExitOutcome && !hasUnfinishedWork) {
-      return true
+      return { ok: true }
     }
     // A queued message is the delivery loop's to settle: it was never handed to this child. A
     // child that never proved its start accepted nothing either — input is written only after it
@@ -189,10 +194,14 @@ export async function settleStructuredAgentSessionDeadGeneration(input: {
         mutations: chunk.mutations
       })
     }
-    return true
+    return { ok: true }
   } catch (error) {
-    input.onError?.(input.sessionId, error)
-    return false
+    traceAgentSessionError({
+      step: 'dead-generation-settlement',
+      sessionId: input.sessionId,
+      error
+    })
+    return { ok: false, error }
   }
 }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-delivery-loop.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-delivery-loop.ts
index 373e2ae3c36e..43f400446a70 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-delivery-loop.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-delivery-loop.ts
@@ -38,6 +38,7 @@ import {
 import { failedProviderChildStart } from './structured-agent-session-provider-child'
 import { handOverSubmission } from './structured-agent-session-turns'
 import { structuredAgentSessionCommandRunning } from './structured-agent-session-command-turn'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionDeliveryLoopDeps = {
   sessions: ReadonlyMap<string, StructuredAgentSessionHostSession>
@@ -55,7 +56,6 @@ export type StructuredAgentSessionDeliveryLoopDeps = {
   conversationFence: (sessionId: string) => number
   /** Who the chat's failure sentences name. */
   failureTextContext: (sessionId: string) => AgentSessionFailureWordsContext
-  onError: (sessionId: string, error: unknown) => void
   record: (sessionId: string) => AgentSessionRecord | null
   flushStreamedEvents: (sessionId: string) => Promise<void>
   now: () => number
@@ -125,14 +125,18 @@ export class StructuredAgentSessionDeliveryLoop {
       }
     } catch (error) {
       // The error is Orca's own and goes to the log; the chat says only that Orca failed.
-      this.deps.onError(sessionId, error)
+      traceAgentSessionError({ step: 'delivery-loop', sessionId, error })
       const cause = { hostFault: true } as const
       await this.deps
         .serialize(sessionId, () => this.fail(sessionId, { startKey: null, cause }))
         .catch((failure: unknown) => {
           // Rows left queued are rejected by the next open, or by the next loop an accept wakes.
           this.running.delete(sessionId)
-          this.deps.onError(sessionId, failure)
+          traceAgentSessionError({
+            step: 'delivery-loop-failure-settlement',
+            sessionId,
+            error: failure
+          })
         })
     }
   }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts
index f7a50627370e..fdd17395704b 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-event-recovery.ts
@@ -10,6 +10,7 @@ import type {
 import type { StructuredAgentSessionSinkBarrier } from './structured-agent-session-event-sink'
 import { settleStructuredAgentSessionProviderStarted } from './structured-agent-session-provider-started'
 import { settleUnexpectedStructuredAgentSessionExit } from './structured-agent-session-unexpected-exit'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export class StructuredAgentSessionEventRecovery {
   private readonly sinkFailures = new Set<string>()
@@ -24,7 +25,6 @@ export class StructuredAgentSessionEventRecovery {
       publishStatus?: (sessionId: string) => void
       serialize: <T>(sessionId: string, task: () => Promise<T>) => Promise<T>
       now: () => number
-      onBarrierError: (sessionId: string, error: unknown) => void
     }
   ) {}
 
@@ -58,7 +58,9 @@ export class StructuredAgentSessionEventRecovery {
         } as const
       })
       .then((event) => (event ? this.handle(event) : undefined))
-      .catch((recoveryError) => this.context.onBarrierError(sessionId, recoveryError))
+      .catch((error: unknown) =>
+        traceAgentSessionError({ step: 'sink-failure-recovery', sessionId, error })
+      )
       .finally(() => this.sinkFailures.delete(sessionId))
   }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts
index 2d0766a4bce8..cea1e5f8edaa 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink-queue.ts
@@ -45,7 +45,7 @@ export class StructuredAgentSessionSinkQueue {
   constructor(
     private readonly deps: {
       watermarks: StructuredAgentSessionSinkWatermarks
-      onError?: (error: unknown) => void
+      onFailure: (error: unknown) => void
       readingControl?: StructuredAgentSessionReadingControl
       onBackpressureChange?: (
         backpressured: boolean,
@@ -212,7 +212,7 @@ export class StructuredAgentSessionSinkQueue {
   private fail = (error: unknown): void => {
     if (this.failure === null) {
       this.failure = { error }
-      this.deps.onError?.(error)
+      this.deps.onFailure(error)
     }
     this.queue.length = 0
     this.queuedBytes = 0
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.test.ts
index 46dc8fbf7e44..7a8a1cfb2bbd 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.test.ts
@@ -91,7 +91,7 @@ function target(
 describe('deferred structured agent-session event sink', () => {
   it('buffers writes made before the journal exists and drains them in arrival order', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
 
     deferred.sink.appendItem(identity(0), BODY, { turnScope: AGENT_JOURNAL_THREAD_SCOPE })
     deferred.sink.appendItem(identity(1), BODY, { turnScope: AGENT_JOURNAL_THREAD_SCOPE })
@@ -110,7 +110,7 @@ describe('deferred structured agent-session event sink', () => {
 
   it('writes at the fence bound at submission time, so a rebind cannot backdate a write', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind(target(1, log))
 
     deferred.sink.appendItem(identity(0), BODY, { turnScope: AGENT_JOURNAL_THREAD_SCOPE })
@@ -127,7 +127,7 @@ describe('deferred structured agent-session event sink', () => {
 
   it('buffers replacement-acquisition events while unbound', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind(target(1, log))
     deferred.unbind()
 
@@ -141,7 +141,7 @@ describe('deferred structured agent-session event sink', () => {
 
   it('resolves a lifecycle transition after journal bind and skips an existing state', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
 
     expect(
       deferred.sink.tryAppendLifecycleTransition?.(identity(0), BODY, () => identity(1), {
@@ -166,7 +166,7 @@ describe('deferred structured agent-session event sink', () => {
 
   it('drops buffered and later writes once closed, and refuses to rebind', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
 
     deferred.sink.appendItem(identity(0), BODY, { turnScope: AGENT_JOURNAL_THREAD_SCOPE })
     deferred.close()
@@ -182,7 +182,7 @@ describe('deferred structured agent-session event sink', () => {
     const errors: unknown[] = []
     const readingControl = { pauseReading: vi.fn(), resumeReading: vi.fn() }
     const deferred = createDeferredStructuredAgentSessionEventSink({
-      onError: (error) => errors.push(error),
+      onFailure: (error) => errors.push(error),
       readingControl
     })
     deferred.bind(target(4, log, 0))
@@ -206,7 +206,8 @@ describe('deferred structured agent-session event sink', () => {
   })
 
   it('replaces a failed cached sink before recovery drain', async () => {
-    const runtime = new StructuredAgentSessionHostRuntimeState({ store: {} } as never)
+    // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: only the runtime state's event sinks run here; the store is never read.
+    const runtime = new StructuredAgentSessionHostRuntimeState({ store: {} } as never, () => {})
     const failed = runtime.eventSinkFor('session-1')
     failed.bind(target(1, [], 0))
     failed.sink.appendItem(identity(0), BODY, { turnScope: AGENT_JOURNAL_THREAD_SCOPE })
@@ -226,6 +227,7 @@ describe('deferred structured agent-session event sink', () => {
     const changes: boolean[] = []
     const readingControl = { pauseReading: vi.fn(), resumeReading: vi.fn() }
     const deferred = createDeferredStructuredAgentSessionEventSink({
+      onFailure: () => {},
       watermarks: {
         maxQueuedBytes: 1_000_000,
         lowQueuedBytes: 0,
@@ -262,6 +264,7 @@ describe('deferred structured agent-session event sink', () => {
   it('admits a resolved append and publication as one bounded operation', async () => {
     const log: Recorded[] = []
     const deferred = createDeferredStructuredAgentSessionEventSink({
+      onFailure: () => {},
       watermarks: {
         pauseQueuedOperations: 1,
         maxQueuedOperations: 2,
@@ -299,6 +302,7 @@ describe('deferred structured agent-session event sink', () => {
     const changes: boolean[] = []
     const readingControl = { pauseReading: vi.fn(), resumeReading: vi.fn() }
     const deferred = createDeferredStructuredAgentSessionEventSink({
+      onFailure: () => {},
       watermarks: {
         pauseQueuedBytes: 1,
         maxQueuedBytes: 1_000_000,
@@ -329,7 +333,7 @@ describe('deferred structured agent-session event sink', () => {
     const log: Recorded[] = []
     const errors: unknown[] = []
     const deferred = createDeferredStructuredAgentSessionEventSink({
-      onError: (error) => errors.push(error),
+      onFailure: (error) => errors.push(error),
       watermarks: {
         pauseQueuedBytes: 1,
         maxQueuedBytes: 1,
@@ -364,6 +368,7 @@ describe('deferred structured agent-session event sink', () => {
     const firstControl = { pauseReading: vi.fn(), resumeReading: vi.fn() }
     const secondControl = { pauseReading: vi.fn(), resumeReading: vi.fn() }
     const deferred = createDeferredStructuredAgentSessionEventSink({
+      onFailure: () => {},
       watermarks: {
         pauseQueuedBytes: 1,
         maxQueuedBytes: 1_000_000,
@@ -395,7 +400,7 @@ describe('deferred structured agent-session event sink', () => {
 
   it('replaces a queued same-item checkpoint before it runs', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const options = { coalescingKey: 'checkpoint:item-1', turnScope: AGENT_JOURNAL_THREAD_SCOPE }
 
     deferred.sink.appendItem(identity(0), BODY, options)
@@ -411,7 +416,7 @@ describe('deferred structured agent-session event sink', () => {
     // The journal applies a settlement id once and skips any later batch with it,
     // so the queue must not let a later batch replace one it has not run yet.
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const batch = (ordinal: number) => [
       {
         kind: 'item' as const,
@@ -440,7 +445,7 @@ describe('deferred structured agent-session event sink', () => {
 
   it('keeps a replacement checkpoint after distinct intervening operations', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const options = { coalescingKey: 'checkpoint:item-1', turnScope: AGENT_JOURNAL_THREAD_SCOPE }
 
     deferred.sink.appendItem(identity(0), BODY, options)
@@ -457,7 +462,7 @@ describe('deferred structured agent-session event sink', () => {
 
   it('coalesces provider activity as a publication without a journal write', async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
 
     deferred.sink.setActivity?.({ turnId: 'turn-1', text: 'Thinking' })
     deferred.sink.setActivity?.({ turnId: 'turn-1', text: 'Checking the result' })
@@ -486,7 +491,7 @@ describe('producer linkage reaches the journal through every append path', () =>
   it('forwards the whole bundle on the plain and try append paths', async () => {
     for (const append of ['appendItem', 'tryAppendItem'] as const) {
       const log: Recorded[] = []
-      const deferred = createDeferredStructuredAgentSessionEventSink()
+      const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
       deferred.bind(target(5, log))
       deferred.sink[append]?.(identity(1), BODY, {
         ...LINKAGE,
@@ -510,7 +515,7 @@ describe('producer linkage reaches the journal through every append path', () =>
       'tryAppendLifecycleTransition'
     ] as const) {
       const log: Recorded[] = []
-      const deferred = createDeferredStructuredAgentSessionEventSink()
+      const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
       deferred.bind(target(5, log))
       deferred.sink[append]?.(identity(1), BODY, () => identity(1), {
         ...LINKAGE,
@@ -530,7 +535,7 @@ describe('producer linkage reaches the journal through every append path', () =>
     // would stamp whoever opened the batch onto all of them. Both callers are
     // single-producer today; a mixed batch would have to stamp per mutation.
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind(target(5, log))
     deferred.sink.appendLifecycleBatch?.(
       'settle-1',
@@ -547,7 +552,7 @@ describe('producer linkage reaches the journal through every append path', () =>
 
   it("writes no linkage keys at all for the session's own agent", async () => {
     const log: Recorded[] = []
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.bind(target(5, log))
     deferred.sink.appendItem(identity(1), BODY, { turnScope: AGENT_JOURNAL_THREAD_SCOPE })
     await deferred.drained()
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts
index 121fb865db4a..179645c562de 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-event-sink.ts
@@ -193,18 +193,17 @@ const DEFAULT_WATERMARKS: StructuredAgentSessionSinkWatermarks = {
   maxLifecycleQueuedOperations: 1_024
 }
 
-export function createDeferredStructuredAgentSessionEventSink(
-  deps: {
-    onError?: (error: unknown) => void
-    watermarks?: Partial<StructuredAgentSessionSinkWatermarks>
-    readingControl?: StructuredAgentSessionReadingControl
-    onBackpressureChange?: (backpressured: boolean, state: StructuredAgentSessionSinkState) => void
-  } = {}
-): DeferredStructuredAgentSessionEventSink {
+export function createDeferredStructuredAgentSessionEventSink(deps: {
+  /** The sink failed for good, or refused a lifecycle batch: what the provider writes is lost. */
+  onFailure: (error: unknown) => void
+  watermarks?: Partial<StructuredAgentSessionSinkWatermarks>
+  readingControl?: StructuredAgentSessionReadingControl
+  onBackpressureChange?: (backpressured: boolean, state: StructuredAgentSessionSinkState) => void
+}): DeferredStructuredAgentSessionEventSink {
   const watermarks = { ...DEFAULT_WATERMARKS, ...deps.watermarks }
   const queue = new StructuredAgentSessionSinkQueue({
     watermarks,
-    ...(deps.onError ? { onError: deps.onError } : {}),
+    onFailure: deps.onFailure,
     ...(deps.readingControl ? { readingControl: deps.readingControl } : {}),
     ...(deps.onBackpressureChange ? { onBackpressureChange: deps.onBackpressureChange } : {})
   })
@@ -280,7 +279,7 @@ export function createDeferredStructuredAgentSessionEventSink(
       appendLifecycleBatch: (settlementId, mutations, options = {}) => {
         const admission = appendLifecycleBatch(settlementId, mutations, options)
         if (!admission.accepted) {
-          deps.onError?.(
+          deps.onFailure(
             new Error(
               `lifecycle journal batch ${settlementId} rejected by sink ${admission.reason}`
             )
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.test.ts
index 8fc810de2a4d..42b844722c71 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.test.ts
@@ -44,10 +44,14 @@ function context(): StructuredAgentSessionEvictionContext & { order: string[] }
 }
 
 function runtimeState(): StructuredAgentSessionHostRuntimeState {
-  return new StructuredAgentSessionHostRuntimeState({
-    store: {} as never,
-    adapter: {} as never
-  } as never)
+  return new StructuredAgentSessionHostRuntimeState(
+    // oxlint-disable-next-line typescript/consistent-type-assertions -- SAFETY: these tests use only the runtime state's event sinks; the store and adapter are never read.
+    {
+      store: {} as never,
+      adapter: {} as never
+    } as never,
+    () => {}
+  )
 }
 
 describe('structured agent session eviction', () => {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.ts
index 226781117bdf..37c6e9557d72 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-eviction.ts
@@ -24,6 +24,7 @@ import {
 import type { DeferredStructuredAgentSessionEventSink } from './structured-agent-session-event-sink'
 import type { StructuredAgentSessionStopVerdict } from './structured-agent-session-host-types'
 import { withTimeout } from '../../../shared/promise-timeout-fallback'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionEvictionContext = {
   sessionId: string
@@ -72,8 +73,12 @@ export const STRUCTURED_AGENT_SESSION_EVICTION_STEPS: readonly StructuredAgentSe
         await withTimeout<unknown>(context.eventSink.drained(), SNAPSHOT_DRAIN_TIMEOUT_MS, null)
         try {
           context.beforeProviderChildStop()
-        } catch {
-          console.warn('[structured-agent-session] capturing recovery witness failed')
+        } catch (error) {
+          traceAgentSessionError({
+            step: 'recovery-witness-capture',
+            sessionId: context.sessionId,
+            error
+          })
         }
       }
     },
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-delivery.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-delivery.ts
index ed2e48fd562b..d5b001ddfb6a 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-delivery.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-delivery.ts
@@ -21,6 +21,7 @@ import type {
 import { structuredAgentSessionConversationFence } from './structured-agent-session-provider-child'
 import { structuredAgentSessionFailureWordsContext } from './structured-agent-session-send-preparation'
 import { recoverStructuredRewind } from './structured-rewind-recovery'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionConversationDelivery = {
   loop: StructuredAgentSessionDeliveryLoop
@@ -70,7 +71,6 @@ export function createStructuredAgentSessionConversationDelivery(input: {
         deps.store.getRecord(sessionId),
         sessions.get(sessionId)?.journal
       ),
-    onError: (sessionId, error) => deps.onEventSinkError?.({ sessionId, error }),
     record: (sessionId) => deps.store.getRecord(sessionId),
     flushStreamedEvents: input.flushStreamedEvents,
     now: () => deps.now?.() ?? Date.now()
@@ -107,7 +107,7 @@ export function createStructuredAgentSessionConversationDelivery(input: {
       })
       .catch((error: unknown) => {
         wakesQueued.delete(sessionId)
-        deps.onEventSinkError?.({ sessionId, error })
+        traceAgentSessionError({ step: 'delivery-wake', sessionId, error })
       })
   }
   // A chat open before its owner's death was proven revises what its open settled. Queued, never
@@ -120,7 +120,9 @@ export function createStructuredAgentSessionConversationDelivery(input: {
             resettleOpenStructuredAgentSessionConversation(deps, sessionId, sessions.get(sessionId))
           )
         )
-        .catch((error: unknown) => deps.onEventSinkError?.({ sessionId, error }))
+        .catch((error: unknown) =>
+          traceAgentSessionError({ step: 'death-evidence-resettle', sessionId, error })
+        )
     }
   })
   return {
@@ -151,6 +153,6 @@ async function settleInterruptedCommands(
   try {
     await recoverStructuredRewind(deps.store, sessionId, session.journal, fence)
   } catch (error) {
-    deps.onEventSinkError?.({ sessionId, error })
+    traceAgentSessionError({ step: 'rewind-recovery', sessionId, error })
   }
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-lifetime.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-lifetime.ts
index f2140c98fbc7..e1ccc6b0ce16 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-lifetime.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-lifetime.ts
@@ -30,6 +30,7 @@ import {
 } from './structured-agent-session-provider-child'
 import { releaseStoredStructuredAgentSessionOwner } from './structured-agent-session-lease-release'
 import { settleStructuredAgentSessionDeadGeneration } from './structured-agent-session-dead-generation-settlement'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionLifetimeContext = {
   deps: StructuredAgentSessionHostDeps
@@ -45,7 +46,7 @@ export type StructuredAgentSessionLifetimeContext = {
   }
 }
 
-type ConversationCloseDeps = Pick<StructuredAgentSessionHostDeps, 'onEventSinkError'> & {
+type ConversationCloseDeps = {
   store: Pick<StructuredAgentSessionHostDeps['store'], 'getRecord'>
 }
 
@@ -62,7 +63,7 @@ export async function abandonQueuedStructuredAgentSessionMessages(
       structuredAgentSessionConversationFence(deps.store, sessionId),
       agentSessionFailureWords(agentSessionFailureFact('chatClosed'), { surface: 'rejection' })
     )
-    .catch((error: unknown) => deps.onEventSinkError?.({ sessionId, error }))
+    .catch((error: unknown) => traceAgentSessionError({ step: 'queued-abandon', sessionId, error }))
 }
 
 /** The wind-down this host owes for the session's child. A live child always owes one, whatever a
@@ -100,7 +101,6 @@ export async function stopStructuredAgentSessionAgentUnderSerialize(
   const owed = owedProviderChildWindDown(session)
   session.owesProviderChildWindDown = owed
   const stopping = session.child
-  let settlementError: unknown
   const eviction: StructuredAgentSessionEvictionContext = {
     sessionId,
     // The retry must not re-stop a child the adapter already proved gone, so this stays honest.
@@ -137,15 +137,11 @@ export async function stopStructuredAgentSessionAgentUnderSerialize(
         settlementId: `expected-close:${sessionId}:${fence}:${owed?.generation ?? 'unknown'}`,
         pendingSubmissionReason: 'provider_closed_before_acknowledgement',
         verdict: { state: 'interrupted', completedAt: context.now() },
-        showUnexpectedExitOutcome: false,
-        onError: (id, error) => {
-          settlementError = error
-          context.deps.onEventSinkError?.({ sessionId: id, error })
-        }
+        showUnexpectedExitOutcome: false
       })
-      if (!settled) {
+      if (!settled.ok) {
         // Without the cause the log names the step and nothing else.
-        throw new Error('dead generation work settlement failed', { cause: settlementError })
+        throw new Error('dead generation work settlement failed', { cause: settled.error })
       }
     },
     releaseLease: async () => {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.test.ts
index 5f336345b5e6..c129facf9f0a 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.test.ts
@@ -13,6 +13,11 @@ import {
 } from '../agent-session-journal/journal-host-database-test-support'
 import { StructuredAgentSessionHostRuntimeState } from './structured-agent-session-host-runtime-state'
 import type { StructuredAgentSessionHostDeps } from './structured-agent-session-host'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const NOW = 1_800_000_000_000
 
@@ -70,7 +75,7 @@ function runtimeState(
     claimKeyId: 'key-1',
     probeOwner
   } as StructuredAgentSessionHostDeps
-  return new StructuredAgentSessionHostRuntimeState(deps)
+  return new StructuredAgentSessionHostRuntimeState(deps, () => {})
 }
 
 function liveRecord(): AgentSessionRecord {
@@ -129,7 +134,6 @@ describe('host runtime-state owner probe', () => {
 
   it('does not force-close a provider for transient lease probe errors', async () => {
     const onEventSinkFailure = vi.fn()
-    const onEventSinkError = vi.fn()
     const probeOwner = vi.fn(async () => {
       throw new Error('lease probe unavailable')
     })
@@ -143,8 +147,7 @@ describe('host runtime-state owner probe', () => {
       adapter: {},
       journalDatabase: openTestJournalHostDatabase(stateDirectory),
       claimKeyId: 'key-1',
-      probeOwner,
-      onEventSinkError
+      probeOwner
     } as unknown as StructuredAgentSessionHostDeps
     const state = new StructuredAgentSessionHostRuntimeState(deps, onEventSinkFailure)
 
@@ -152,7 +155,8 @@ describe('host runtime-state owner probe', () => {
       state as unknown as { leaseRenewer: { renewNow: () => Promise<void> } }
     ).leaseRenewer.renewNow()
 
-    expect(onEventSinkError).toHaveBeenCalledWith({
+    expect(traceAgentSessionError).toHaveBeenCalledWith({
+      step: 'lease-probe',
       sessionId: record.sessionId,
       error: expect.any(Error)
     })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.ts
index 63f37a37590e..e59e4b4c0529 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-runtime-state.ts
@@ -8,25 +8,22 @@ import {
 import type { StructuredAgentSessionHostDeps } from './structured-agent-session-host'
 import { StructuredAgentSessionLeaseRenewer } from './structured-agent-session-lease-renewer'
 import { resolveStructuredSessionRecovery } from './structured-agent-session-recovery-resolution'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export class StructuredAgentSessionHostRuntimeState {
   private readonly eventSinks = new Map<string, DeferredStructuredAgentSessionEventSink>()
   private readonly leaseRenewer: StructuredAgentSessionLeaseRenewer
-  private readonly onEventSinkFailure?: (sessionId: string, error: unknown) => void
 
   constructor(
     private readonly deps: StructuredAgentSessionHostDeps,
-    onEventSinkFailure?: (sessionId: string, error: unknown) => void
+    /** Forces the session's provider down: its journal can no longer take what it writes. */
+    private readonly onEventSinkFailure: (sessionId: string, error: unknown) => void
   ) {
-    this.onEventSinkFailure = onEventSinkFailure
     this.leaseRenewer = new StructuredAgentSessionLeaseRenewer({
       store: deps.store,
       probe: (record) => this.probeRecord(record),
       ...(deps.probeOwners ? { probeMany: deps.probeOwners } : {}),
-      now: () => deps.now?.() ?? Date.now(),
-      // Lease/ownership failures are transient and stay on the visible lease-error path.
-      // Only deferred sink I/O failures are terminal and may force-close a provider.
-      onError: ({ sessionId, error }) => deps.onEventSinkError?.({ sessionId, error })
+      now: () => deps.now?.() ?? Date.now()
     })
   }
 
@@ -67,11 +64,11 @@ export class StructuredAgentSessionHostRuntimeState {
   mintEventSink(sessionId: string): DeferredStructuredAgentSessionEventSink {
     const minted: DeferredStructuredAgentSessionEventSink =
       createDeferredStructuredAgentSessionEventSink({
-        onError: (error) => {
-          this.deps.onEventSinkError?.({ sessionId, error })
+        onFailure: (error) => {
+          traceAgentSessionError({ step: 'event-sink', sessionId, error })
           // Only the session's own sink may force its provider down; an attempt's never is.
           if (this.eventSinks.get(sessionId) === minted) {
-            this.onEventSinkFailure?.(sessionId, error)
+            this.onEventSinkFailure(sessionId, error)
           }
         }
       })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-tabs.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-tabs.ts
index 8a18040daf35..6ebf10703b7d 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-tabs.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-tabs.ts
@@ -1,4 +1,5 @@
 import type { AgentSessionRecord } from '../../../shared/agent-session-record'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /**
  * Chat-tab visibility is the deletion funnel: every path that removes a chat as a user-facing
@@ -24,9 +25,11 @@ export function setStructuredAgentSessionTabVisibility(
   tabId?: string
 ): Promise<void> {
   if (!visible) {
-    void host.restartResume.dismiss([sessionId]).catch(() => {
-      console.warn('[structured-agent-session] forgetting recovery records on chat close failed')
-    })
+    void host.restartResume
+      .dismiss([sessionId])
+      .catch((error: unknown) =>
+        traceAgentSessionError({ step: 'recovery-records-forget', sessionId, error })
+      )
   }
   return host.deps.store.setSessionTabVisibility(sessionId, visible, tabId)
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.test.ts
index aa8692a0c73f..81976971fc64 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.test.ts
@@ -108,7 +108,9 @@ describe('structured agent-session host teardown', () => {
       await teardown
       expect(cleaned).toHaveBeenCalledTimes(4)
       expect(warning).toHaveBeenCalledWith(
-        '[structured-agent-session] recording recovery capsule failed'
+        '[agent-session] recovery-capsule-record failed',
+        {},
+        expect.any(String)
       )
       expect(vi.getTimerCount()).toBe(0)
     } finally {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.ts
index 4ce0b3885adf..c749e31876d6 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-teardown.ts
@@ -17,6 +17,7 @@ import {
 } from './structured-agent-session-host-lifetime'
 import { withTimeout } from '../../../shared/promise-timeout-fallback'
 import type { StructuredAgentSessionHostSession } from './structured-agent-session-host-types'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionTeardownPhase = {
   name: string
@@ -73,8 +74,8 @@ export function structuredAgentSessionHostTeardownPhases(collaborators: {
       run: () => {
         try {
           collaborators.beginResumeMarkers()
-        } catch {
-          console.warn('[structured-agent-session] capturing recovery witnesses failed')
+        } catch (error) {
+          traceAgentSessionError({ step: 'recovery-witness-begin', error })
         }
       }
     },
@@ -89,9 +90,7 @@ export function structuredAgentSessionHostTeardownPhases(collaborators: {
       name: 'record-resume-markers',
       run: () =>
         withPhaseTimeout(collaborators.recordResumeMarkers, RESUME_MARKER_RECORD_TIMEOUT_MS).catch(
-          () => {
-            console.warn('[structured-agent-session] recording recovery capsule failed')
-          }
+          (error: unknown) => traceAgentSessionError({ step: 'recovery-capsule-record', error })
         )
     },
     { name: 'flush-event-sinks', run: () => collaborators.runtimeState.flushAllEventSinks() }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host-types.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host-types.ts
index 80ea85e86835..cf640cf86acc 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host-types.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host-types.ts
@@ -119,7 +119,6 @@ export type StructuredAgentSessionHostDeps = {
   idleSweep?: { intervalMs?: number; idleMs?: number }
   /** Whether an orchestration dispatch still owns this session's worker; absent answers no. */
   hasOpenDispatch?: (record: AgentSessionRecord) => boolean
-  onEventSinkError?: (input: { sessionId: string; error: unknown }) => void
   /** Every status projection this host publishes. `replay` marks a re-projection of state the host
    *  already knew (restore, an arriving subscriber) rather than a fresh journal edge. */
   onSessionStatusChanged?: (
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
index 79a129118ee0..644b6e7ceab8 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-host.ts
@@ -68,7 +68,6 @@ export class StructuredAgentSessionHost {
       this.subscribers.publish(sessionId, journal)
       this.conversationDelivery.afterCommit(sessionId, journal)
     },
-    onDeliveryError: (sessionId, error) => this.deps.onEventSinkError?.({ sessionId, error }),
     onOpened: (sessionId) => this.queued.drain.schedule(sessionId),
     now: () => this.now()
   })
@@ -156,8 +155,7 @@ export class StructuredAgentSessionHost {
         ),
       publishStatus: this.clientDelivery.publishStatusAndSettlement,
       serialize: (sessionId, task) => this.tasks.trackAttach(this.serialize(sessionId, task)),
-      now: () => this.now(),
-      onBarrierError: (sessionId, error) => deps.onEventSinkError?.({ sessionId, error })
+      now: () => this.now()
     })
     this.restartResume = createStructuredAgentSessionRestartResume(
       deps,
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.test.ts
index 25288dc64905..e6a5a50ded0f 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.test.ts
@@ -18,6 +18,11 @@ import {
   type RestTestRig
 } from './structured-agent-session-rest-test-rig'
 import { StructuredAgentSessionIdleSweep } from './structured-agent-session-idle-sweep'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 let rig: RestTestRig
 
@@ -306,12 +311,11 @@ describe('the idle sweep with no child running (P2-22 ii)', () => {
       hasOpenDispatch: () => false,
       stopAgent,
       stopStartingAgent: stopAgent,
-      closeConversation,
-      onError: (_id, error) => {
-        throw error
-      }
+      closeConversation
     })
+    vi.mocked(traceAgentSessionError).mockClear()
     await sweep.tick()
+    expect(traceAgentSessionError).not.toHaveBeenCalled()
     expect(stopAgent).not.toHaveBeenCalled()
     expect(closeConversation).toHaveBeenCalledWith(SESSION)
   })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.ts
index 1fc223808f6b..6708353b0f1d 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-idle-sweep.ts
@@ -14,6 +14,7 @@ import { isQueuedAgentJournalSubmission } from '../../../shared/agent-session-qu
 import type { AgentJournalRenderItem } from '../../../shared/agent-session-journal-types'
 import type { AgentSessionBackgroundTaskState } from '../../../shared/agent-session-wire'
 import type { StructuredAgentSessionHostSession } from './structured-agent-session-host-types'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export const STRUCTURED_AGENT_SESSION_IDLE_SWEEP_INTERVAL_MS = 5 * 60_000
 export const STRUCTURED_AGENT_SESSION_IDLE_MS = 30 * 60_000
@@ -34,7 +35,6 @@ export type StructuredAgentSessionIdleSweepDeps = {
   stopAgent: (sessionId: string) => Promise<void>
   stopStartingAgent: (sessionId: string) => Promise<void>
   closeConversation: (sessionId: string) => Promise<boolean>
-  onError: (sessionId: string, error: unknown) => void
   intervalMs?: number
   idleMs?: number
 }
@@ -84,7 +84,9 @@ export class StructuredAgentSessionIdleSweep {
         [...this.deps.sessions.keys()].map((sessionId) =>
           this.deps
             .serialize(sessionId, () => this.tickUnderSerialize(sessionId))
-            .catch((error: unknown) => this.deps.onError(sessionId, error))
+            .catch((error: unknown) =>
+              traceAgentSessionError({ step: 'idle-sweep', sessionId, error })
+            )
         )
       )
     } finally {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-late-settlement.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-late-settlement.test.ts
index 510384f3e484..e1810671b8df 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-late-settlement.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-late-settlement.test.ts
@@ -289,6 +289,40 @@ describe('settling a send the provider proves it received after the ack window',
     ])
   })
 
+  it('reports once when not even the doubt about a dispatch can be recorded', async () => {
+    const settleError = new Error('settlement write refused')
+    const doubtError = new Error('doubt write refused')
+    const resolveDispatch = journal().resolveDispatch.bind(journal())
+    const resolve = vi.spyOn(journal(), 'resolveDispatch').mockImplementation(async (input) => {
+      if (input.state === 'accepted') {
+        throw settleError
+      }
+      if (input.state === 'unknown') {
+        throw doubtError
+      }
+      return resolveDispatch(input)
+    })
+    const warned = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const line = '[agent-session] dispatch-doubt-record failed'
+    const doubtReports = () => warned.mock.calls.filter(([message]) => message === line)
+    try {
+      await host.send(CALLER, sendParams('an outcome nothing could record'))
+      await vi.waitFor(() => expect(doubtReports()).toHaveLength(1))
+      expect(doubtReports()).toEqual([[line, { sessionId: SESSION }, doubtError]])
+      // The settlement's own failure is still what the delivery loop reports.
+      await vi.waitFor(() =>
+        expect(warned).toHaveBeenCalledWith(
+          '[agent-session] delivery-loop failed',
+          { sessionId: SESSION },
+          settleError
+        )
+      )
+    } finally {
+      resolve.mockRestore()
+      warned.mockRestore()
+    }
+  })
+
   it('leaves an already accepted send alone', async () => {
     const params = sendParams('ordinary send')
     await host.send(CALLER, params)
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.test.ts
index 9399e4d0242b..f5951ea89e74 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.test.ts
@@ -6,9 +6,15 @@ import {
   agentSessionLeaseFixture,
   agentSessionRecordFixture
 } from '../../../shared/agent-session-record.test-fixture'
+import type { AgentSessionOwnerProbe } from '../../../shared/agent-session-lease-adjudication'
 import type { AgentSessionRecordStore } from '../../runtime/agent-session-record-store'
 import { openTestAgentSessionRecordStore } from '../../runtime/agent-session-record-store-test-harness'
 import { StructuredAgentSessionLeaseRenewer } from './structured-agent-session-lease-renewer'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const NOW = 1_800_000_000_000
 const roots: string[] = []
@@ -144,7 +150,7 @@ describe('structured agent-session lease renewal', () => {
       }
       return records[0]!
     })
-    const onError = vi.fn()
+    vi.mocked(traceAgentSessionError).mockClear()
     const renewer = new StructuredAgentSessionLeaseRenewer({
       store: {
         listRecords: () => records,
@@ -155,15 +161,15 @@ describe('structured agent-session lease renewal', () => {
         outcome: 'identity-matched' as const,
         matchedOn: ['spawn-token' as const]
       }),
-      now: () => NOW + 10_000,
-      onError
+      now: () => NOW + 10_000
     })
 
     await renewer.renewNow()
 
     expect(renewLeases).toHaveBeenCalledOnce()
     expect(renewLease).toHaveBeenCalledTimes(2)
-    expect(onError).toHaveBeenCalledWith({
+    expect(traceAgentSessionError).toHaveBeenCalledExactlyOnceWith({
+      step: 'lease-renewal',
       sessionId: 'session-b',
       error: expect.objectContaining({ message: 'agent_session_checkpoint_stale' })
     })
@@ -241,18 +247,18 @@ describe('structured agent-session lease renewal', () => {
 
   it('stops extending the lease when child proof is no longer sufficient', async () => {
     const store = await liveStore()
-    const onError = vi.fn()
+    vi.mocked(traceAgentSessionError).mockClear()
     const renewer = new StructuredAgentSessionLeaseRenewer({
       store,
       probe: async () => ({ outcome: 'indeterminate', reason: 'probe unavailable' }),
-      now: () => NOW + 10_000,
-      onError
+      now: () => NOW + 10_000
     })
 
     await renewer.renewNow()
 
     expect(store.getRecord('session-renewal')?.lease.lastRenewedAt).toBe(NOW)
-    expect(onError).toHaveBeenCalledWith({
+    expect(traceAgentSessionError).toHaveBeenCalledWith({
+      step: 'lease-renewal',
       sessionId: 'session-renewal',
       error: expect.any(Error)
     })
@@ -281,4 +287,206 @@ describe('structured agent-session lease renewal', () => {
     expect(probe).not.toHaveBeenCalled()
     expect(store.getRecord('session-renewal')?.lease.lastRenewedAt).toBe(NOW)
   })
+
+  describe('a failure that repeats every tick', () => {
+    function liveRecord(sessionId: string) {
+      return agentSessionRecordFixture(
+        agentSessionLeaseFixture({
+          sessionId,
+          runtimeKind: 'native',
+          runtimeFence: 1,
+          ownerProcess: {
+            hostId: 'local',
+            pid: 4200,
+            processStartTimeMs: NOW - 1_000,
+            spawnToken: 'spawn-a'
+          },
+          reservedSpawnToken: 'spawn-a',
+          lastRenewedAt: NOW,
+          leaseDeadlineAt: NOW + 30_000
+        })
+      )
+    }
+
+    /** Each tick's renewal throws whatever `failure` returns for the session, or renews when it
+     *  holds or returns null. */
+    async function stuckRenewer(
+      sessionIds: string[],
+      probe: () => Promise<AgentSessionOwnerProbe> = async () => ({
+        outcome: 'identity-matched',
+        matchedOn: ['spawn-token']
+      }),
+      probeMany?: () => Promise<Map<string, AgentSessionOwnerProbe>>
+    ) {
+      const state: {
+        failure: ((sessionId: string) => Error | null) | null
+        records: string[]
+      } = {
+        failure: () => new Error('agent_session_ownership_unknown'),
+        records: sessionIds
+      }
+      const store = await liveStore()
+      vi.spyOn(store, 'listRecords').mockImplementation(() => state.records.map(liveRecord))
+      vi.spyOn(store, 'renewLeases').mockRejectedValue(new Error('batch refused'))
+      vi.spyOn(store, 'renewLease').mockImplementation(async (renewal) => {
+        const failure = state.failure?.(renewal.sessionId)
+        if (failure) {
+          throw failure
+        }
+        return liveRecord(renewal.sessionId)
+      })
+      const renewer = new StructuredAgentSessionLeaseRenewer({
+        store,
+        probe,
+        ...(probeMany ? { probeMany } : {}),
+        now: () => NOW + 10_000
+      })
+      return { state, renewer }
+    }
+
+    async function ticks(renewer: StructuredAgentSessionLeaseRenewer, count: number) {
+      for (let tick = 0; tick < count; tick += 1) {
+        await renewer.renewNow()
+      }
+    }
+
+    const renewalRecords = () =>
+      vi
+        .mocked(traceAgentSessionError)
+        .mock.calls.filter(([report]) => report.step === 'lease-renewal')
+
+    it('records it once, however many ticks it repeats', async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { renewer } = await stuckRenewer(['session-a'])
+
+      await ticks(renewer, 5)
+
+      expect(renewalRecords()).toEqual([
+        [
+          {
+            step: 'lease-renewal',
+            sessionId: 'session-a',
+            error: expect.objectContaining({ message: 'agent_session_ownership_unknown' })
+          }
+        ]
+      ])
+    })
+
+    it('keys a store error on its code, not its per-attempt temp path', async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { state, renewer } = await stuckRenewer(['session-a'])
+      let attempt = 0
+      state.failure = () =>
+        Object.assign(
+          new Error(`EACCES: permission denied, open 'records.${(attempt += 1)}.tmp'`),
+          {
+            code: 'EACCES'
+          }
+        )
+
+      await ticks(renewer, 3)
+
+      expect(renewalRecords()).toHaveLength(1)
+    })
+
+    it('records it again after the session renews, and when the failure changes', async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { state, renewer } = await stuckRenewer(['session-a'])
+      const unknown = state.failure
+
+      await ticks(renewer, 2)
+      state.failure = null
+      await ticks(renewer, 1)
+      state.failure = unknown
+      await ticks(renewer, 2)
+      expect(renewalRecords()).toHaveLength(2)
+
+      state.failure = () => new Error('agent_session_checkpoint_stale')
+      await ticks(renewer, 2)
+      expect(renewalRecords().map(([report]) => String(report.error))).toEqual([
+        'Error: agent_session_ownership_unknown',
+        'Error: agent_session_ownership_unknown',
+        'Error: agent_session_checkpoint_stale'
+      ])
+    })
+
+    it('forgets a session that stops being renewable', async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { state, renewer } = await stuckRenewer(['session-a'])
+
+      await ticks(renewer, 1)
+      state.records = []
+      await ticks(renewer, 1)
+      state.records = ['session-a']
+      await ticks(renewer, 1)
+
+      expect(renewalRecords()).toHaveLength(2)
+    })
+
+    it('records a probe that keeps failing once', async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { renewer } = await stuckRenewer(['session-a'], async () => {
+        throw new Error('probe unavailable')
+      })
+
+      await ticks(renewer, 3)
+
+      expect(
+        vi
+          .mocked(traceAgentSessionError)
+          .mock.calls.filter(([report]) => report.step === 'lease-probe')
+      ).toHaveLength(1)
+    })
+
+    it('records a batch probe that keeps failing once per session', async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { renewer } = await stuckRenewer(['session-a', 'session-b'], undefined, async () => {
+        throw new Error('owner probe unavailable')
+      })
+
+      await ticks(renewer, 3)
+
+      expect(
+        vi
+          .mocked(traceAgentSessionError)
+          .mock.calls.filter(([report]) => report.step === 'lease-probe')
+          .map(([report]) => report.sessionId)
+      ).toEqual(['session-a', 'session-b'])
+    })
+
+    it("clears only the renewed session's failure", async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { state, renewer } = await stuckRenewer(['session-a', 'session-b'])
+      const unknown = state.failure
+
+      await ticks(renewer, 2)
+      state.failure = (sessionId) =>
+        sessionId === 'session-b' ? null : new Error('agent_session_ownership_unknown')
+      await ticks(renewer, 1)
+      state.failure = unknown
+      await ticks(renewer, 2)
+
+      expect(renewalRecords().map(([report]) => report.sessionId)).toEqual([
+        'session-a',
+        'session-b',
+        'session-b'
+      ])
+    })
+
+    it('records an error it cannot key without failing the tick', async () => {
+      vi.mocked(traceAgentSessionError).mockClear()
+      const { state, renewer } = await stuckRenewer(['session-a'])
+      state.failure = () =>
+        Object.defineProperty(new Error('agent_session_ownership_unknown'), 'name', {
+          get: () => {
+            throw new Error('hostile name')
+          }
+        })
+
+      await expect(renewer.renewNow()).resolves.toBeUndefined()
+      await expect(renewer.renewNow()).resolves.toBeUndefined()
+
+      expect(renewalRecords()).toHaveLength(1)
+    })
+  })
 })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.ts
index a61e11b6f4f1..b53a568ab975 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-lease-renewer.ts
@@ -4,15 +4,23 @@ import {
   AGENT_SESSION_LEASE_TTL_MS,
   type AgentSessionRecordStore
 } from '../../runtime/agent-session-record-store'
+import {
+  traceAgentSessionError,
+  type AgentSessionErrorStep
+} from '../../observability/agent-session-error-trace'
 
 const RENEW_INTERVAL_MS = Math.floor(AGENT_SESSION_LEASE_TTL_MS / 3)
 
 export class StructuredAgentSessionLeaseRenewer {
   private timer: ReturnType<typeof setInterval> | null = null
   private running = false
-  /** The tick in flight. Never rejects: the timer path reports renewal failures through `onError`,
-   *  and stopping must not turn one into a teardown failure as well. */
+  /** The tick in flight. Never rejects: the timer path reports renewal failures, and stopping must
+   *  not turn one into a teardown failure as well. Lease failures are transient: reported, never
+   *  a reason to force a provider down. */
   private inFlight: Promise<void> = Promise.resolve()
+  /** A stuck lease fails every tick (one store EACCES left ownership_unknown every 10 s, forever),
+   *  so a session's failure is recorded once until it renews or the failure changes. */
+  private readonly recordedFailures = new Map<string, string>()
 
   constructor(
     private readonly input: {
@@ -22,7 +30,6 @@ export class StructuredAgentSessionLeaseRenewer {
         records: readonly AgentSessionRecord[]
       ) => Promise<Map<string, AgentSessionOwnerProbe>>
       now: () => number
-      onError?: (input: { sessionId: string; error: unknown }) => void
       intervalMs?: number
     }
   ) {}
@@ -71,6 +78,12 @@ export class StructuredAgentSessionLeaseRenewer {
         // keeps an orphan pid's lease reading as a healthy owner.
         record.lease.handoffStage !== 'recovering'
     )
+    const renewable = new Set(records.map((record) => record.sessionId))
+    for (const sessionId of this.recordedFailures.keys()) {
+      if (!renewable.has(sessionId)) {
+        this.recordedFailures.delete(sessionId)
+      }
+    }
     const probes = await this.probe(records)
     const renewals: {
       sessionId: string
@@ -103,15 +116,31 @@ export class StructuredAgentSessionLeaseRenewer {
       )
     }
     results.forEach((result, index) => {
+      const renewal = renewals[index]
+      if (!renewal) {
+        return
+      }
       if (result.status === 'rejected') {
-        const renewal = renewals[index]
-        if (renewal) {
-          this.input.onError?.({ sessionId: renewal.sessionId, error: result.reason })
-        }
+        this.recordFailure('lease-renewal', renewal.sessionId, result.reason)
+      } else {
+        this.recordedFailures.delete(renewal.sessionId)
       }
     })
   }
 
+  private recordFailure(
+    step: Extract<AgentSessionErrorStep, 'lease-renewal' | 'lease-probe'>,
+    sessionId: string,
+    error: unknown
+  ): void {
+    const failure = `${step}:${leaseFailureKey(error)}`
+    if (this.recordedFailures.get(sessionId) === failure) {
+      return
+    }
+    this.recordedFailures.set(sessionId, failure)
+    traceAgentSessionError({ step, sessionId, error })
+  }
+
   private async probe(
     records: readonly AgentSessionRecord[]
   ): Promise<Map<string, AgentSessionOwnerProbe>> {
@@ -126,15 +155,29 @@ export class StructuredAgentSessionLeaseRenewer {
         if (result.status === 'fulfilled') {
           probes.set(record.sessionId, result.value)
         } else {
-          this.input.onError?.({ sessionId: record.sessionId, error: result.reason })
+          this.recordFailure('lease-probe', record.sessionId, result.reason)
         }
       }
       return probes
     } catch (error) {
       for (const record of records) {
-        this.input.onError?.({ sessionId: record.sessionId, error })
+        this.recordFailure('lease-probe', record.sessionId, error)
       }
       return new Map()
     }
   }
 }
+
+/** A store error's code, not its message: EACCES names a fresh temp file on every attempt. */
+function leaseFailureKey(error: unknown): string {
+  // Never throws: a hostile getter or toString would otherwise reject the interval's tick.
+  try {
+    if (!(error instanceof Error)) {
+      return String(error)
+    }
+    const code = 'code' in error ? error.code : undefined
+    return `${error.name}:${typeof code === 'string' || typeof code === 'number' ? code : error.message}`
+  } catch {
+    return 'unkeyable'
+  }
+}
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.test.ts
index 71750505fef1..088cb5a8782c 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.test.ts
@@ -127,7 +127,10 @@ it.each([1, 2])(
     expect(result).toEqual(refusal)
     expect(run).toHaveBeenCalledOnce()
     expect(dispatch).not.toHaveBeenCalled()
-    expect(JSON.stringify(warning.mock.calls)).not.toContain('private unbounded disk detail')
+    expect(warning).toHaveBeenCalled()
+    expect(warning.mock.calls.flat().map(String).join(' ')).not.toContain(
+      'private unbounded disk detail'
+    )
   }
 )
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.ts
index e4675bfefb14..e66d00bac311 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-operation-settlement.ts
@@ -2,6 +2,7 @@ import type { AgentSessionMutationEnvelope } from '../../../shared/agent-session
 import type { AgentSessionRecordStore } from '../../runtime/agent-session-record-store'
 import type { MutationPlan } from './structured-agent-session-mutation-plans'
 import type { AgentSessionTurnContext, TurnOutcome } from './structured-agent-session-turns'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** Only thrown while the provider dispatch is still unreachable. */
 export class AgentSessionPreDispatchError extends Error {
@@ -52,14 +53,19 @@ export async function runSettledAgentSessionMutation<TValue>(input: {
     if (input.plan.markUnknownBeforeRun && error instanceof AgentSessionPreDispatchError) {
       throw error
     }
+    const { sessionId } = input.envelope
     try {
       await settle({ status: 'unknown' })
-    } catch {
+    } catch (settleError) {
       // Bookkeeping must not replace the operation's proof of whether dispatch began.
-      console.warn('[structured-agent-session] operation uncertainty persistence failed')
+      traceAgentSessionError({
+        step: 'operation-uncertainty-persist',
+        sessionId,
+        error: settleError
+      })
     }
     if (outcome && !outcome.ok) {
-      console.warn('[structured-agent-session] refused operation settlement failed')
+      traceAgentSessionError({ step: 'refused-operation-settlement', sessionId, error })
       return outcome
     }
     throw error
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-operation-start-refusal.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-operation-start-refusal.test.ts
index 7700a616b382..b0658b71d35b 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-operation-start-refusal.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-operation-start-refusal.test.ts
@@ -31,7 +31,11 @@ describe('an operation whose agent start throws', () => {
         message: "The agent couldn't restart."
       }
     })
-    expect(warn).toHaveBeenCalledWith(expect.stringContaining('starting the agent'), cause)
+    expect(warn).toHaveBeenCalledWith(
+      '[agent-session] operation-agent-start failed',
+      { sessionId: SESSION },
+      cause
+    )
     warn.mockRestore()
   })
 })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-pre-spawn-first-answer.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-pre-spawn-first-answer.test.ts
index db9406785f87..022c32454a78 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-pre-spawn-first-answer.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-pre-spawn-first-answer.test.ts
@@ -157,7 +157,8 @@ describe('a create that fails before any process spawns', () => {
     }
     // What failed is kept for the log.
     expect(warn).toHaveBeenCalledWith(
-      '[agent-session] provider start failed:',
+      '[agent-session] provider-start failed',
+      expect.anything(),
       expect.objectContaining({ message: raw })
     )
   })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-provider-started.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-provider-started.ts
index 8f3c0390aaa1..e1ad7d2847e2 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-provider-started.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-provider-started.ts
@@ -17,6 +17,7 @@ import type {
 } from './structured-agent-session-host-types'
 import { nativeSessionOptionsFromReport } from './structured-agent-session-option-restoration'
 import { markProviderChildStarted } from './structured-agent-session-provider-child'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionProviderStartedContext = {
   deps: StructuredAgentSessionHostDeps
@@ -24,7 +25,6 @@ export type StructuredAgentSessionProviderStartedContext = {
   serialize: <T>(sessionId: string, task: () => Promise<T>) => Promise<T>
   now: () => number
   publishStatus?: (sessionId: string) => void
-  onBarrierError: (sessionId: string, error: unknown) => void
 }
 
 export function settleStructuredAgentSessionProviderStarted(
@@ -46,7 +46,7 @@ export function settleStructuredAgentSessionProviderStarted(
     try {
       await persistStartedOptions(context, event)
     } catch (error) {
-      context.onBarrierError(event.sessionId, error)
+      traceAgentSessionError({ step: 'started-options-persist', sessionId: event.sessionId, error })
     } finally {
       context.publishStatus?.(event.sessionId)
     }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.test.ts
index aa9d31cbf105..3fa5bac7fd7d 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.test.ts
@@ -343,6 +343,38 @@ describe('held drafts', () => {
     })
     expect(await drafts()).toHaveLength(0)
   })
+  it('a hold that cannot be written after a failed conversion is reported once, and the failure still surfaces', async () => {
+    const working = await workingSend()
+    const queued = await send('conversion and hold both fail', 'queue-if-active').result
+    if (!queued.ok || !('queued' in queued.value)) {
+      throw new Error('expected a queued receipt')
+    }
+    const append = vi
+      .spyOn(AgentSessionJournal.prototype, 'appendSubmission')
+      .mockRejectedValueOnce(new Error('disk full'))
+    const holdError = new Error('hold write refused')
+    const hold = vi.spyOn(JournalQueuedMessages.prototype, 'hold').mockRejectedValueOnce(holdError)
+    const warned = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const line = '[agent-session] queued-send-failure-hold failed'
+    const holdReports = () => warned.mock.calls.filter(([message]) => message === line)
+    try {
+      await settleAccepted(working, 'a')
+      await eventually(async () => expect(holdReports()).toHaveLength(1))
+      expect(holdReports()).toEqual([[line, { sessionId: SESSION }, holdError]])
+      // The conversion's own failure is still rethrown to the drain, which reports it.
+      await eventually(async () =>
+        expect(warned).toHaveBeenCalledWith(
+          '[agent-session] queued-drain failed',
+          { sessionId: SESSION },
+          expect.objectContaining({ message: 'disk full' })
+        )
+      )
+    } finally {
+      append.mockRestore()
+      hold.mockRestore()
+      warned.mockRestore()
+    }
+  })
 })
 
 describe('Stop and Delete', () => {
@@ -524,7 +556,11 @@ describe('Stop and Delete', () => {
     const warned = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
     try {
       expect(await stop()).toMatchObject({ ok: true, value: { cancelled: true } })
-      expect(warned).toHaveBeenCalledWith(expect.stringContaining('queue pause'), expect.anything())
+      expect(warned).toHaveBeenCalledWith(
+        '[agent-session] stop-queue-pause failed',
+        expect.anything(),
+        expect.objectContaining({ message: 'disk full' })
+      )
     } finally {
       record.mockRestore()
       warned.mockRestore()
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.ts
index b6d9d2a90beb..eace71f69fb0 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-messages.ts
@@ -30,6 +30,7 @@ import {
   structuredAgentSessionHostInstance,
   structuredQueuePause
 } from './structured-agent-session-queued-pause'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** Budget at accept, in the send schema's own unit (`Buffer.byteLength` of the
  *  serialized blocks); refused readably rather than trimmed. */
@@ -263,7 +264,6 @@ export type QueuedMessageDrainDeps = {
   conversationFence: (sessionId: string) => number
   /** The consumed submission is ordinary #22821 work from here on. */
   wakeDelivery: (sessionId: string) => void
-  onError: (sessionId: string, error: unknown) => void
 }
 
 /**
@@ -312,7 +312,7 @@ export class StructuredAgentSessionQueuedMessageDrain {
       })
       .catch((error: unknown) => {
         this.scheduled.delete(sessionId)
-        this.deps.onError(sessionId, error)
+        traceAgentSessionError({ step: 'queued-drain', sessionId, error })
       })
   }
 
@@ -326,7 +326,7 @@ export class StructuredAgentSessionQueuedMessageDrain {
     if (journal.queuedMessages.settlementOwed() || journal.queuedMessages.deliveredByEchoOwed()) {
       // A live per-row hook was skipped; heal now, before a draft sends, rather than at reopen.
       await journal.queuedMessages.settleOwed().catch((error: unknown) => {
-        this.deps.onError(sessionId, error)
+        traceAgentSessionError({ step: 'queued-owed-settlement', sessionId, error })
       })
     }
     const next = oldestActionableQueuedMessage(journal)
@@ -372,7 +372,9 @@ export class StructuredAgentSessionQueuedMessageDrain {
       // no automatic retry loop.
       await journal.queuedMessages
         .hold({ messageIds: [next.messageId], reason: QUEUED_MESSAGE_PAUSED_SEND_FAILED })
-        .catch(() => {})
+        .catch((holdError: unknown) => {
+          traceAgentSessionError({ step: 'queued-send-failure-hold', sessionId, error: holdError })
+        })
       throw error
     }
     this.deps.wakeDelivery(sessionId)
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-mutations.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-mutations.ts
index 9da974a44a43..30ba137a61e2 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-mutations.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-mutations.ts
@@ -41,6 +41,7 @@ import {
   structuredAgentSessionSendBlock
 } from './structured-agent-session-send-preparation'
 import type { AgentSessionTurnContext, TurnOutcome } from './structured-agent-session-turns'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 function invalid(message: string): {
   ok: false
@@ -127,10 +128,7 @@ export async function carryQueuedMessagesToClearReplacement(
       operationId: input.operationId
     })
   } catch (error) {
-    console.warn("[agent-session] /clear's queued-draft carry skipped:", {
-      sessionId: ctx.sessionId,
-      error: error instanceof Error ? error.message : String(error)
-    })
+    traceAgentSessionError({ step: 'clear-draft-carry', sessionId: ctx.sessionId, error })
   }
 }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-pause.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-pause.ts
index 1428de75fe63..a9a792816eed 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-pause.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-pause.ts
@@ -15,6 +15,7 @@ import { randomUUID } from 'node:crypto'
 import type { AgentSessionQueuePause } from '../../../shared/agent-session-wire'
 import type { AgentSessionJournal } from '../agent-session-journal/journal-store'
 import type { QueuePauseFact } from '../agent-session-journal/queued-message-pause-table'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** A per-process id, minted once per host process like the runtime's own
  *  `runtimeId` (`orca-runtime-runtime-id.ts`); a draft written by another
@@ -88,10 +89,7 @@ export async function retireEndedQueuePause(
       adoptInto: adopt ? hostInstance : null
     })
   } catch (error) {
-    console.warn("[agent-session] a started turn's queue-pause retirement skipped:", {
-      sessionId,
-      error: error instanceof Error ? error.message : String(error)
-    })
+    traceAgentSessionError({ step: 'queue-pause-retire', sessionId, error })
   }
 }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-stop.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-stop.ts
index 16a9b4aeaf77..eb265afb9032 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-stop.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-stop.ts
@@ -12,6 +12,7 @@ import {
   type QueuedMessageRow
 } from '../agent-session-journal/queued-message-table'
 import type { AgentSessionTurnContext, TurnOutcome } from './structured-agent-session-turns'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** The one unsettled-card predicate /clear's carry and the budget share:
  *  waiting or returned. Pending/unknown/accepted deliveries stay outside it. */
@@ -48,19 +49,14 @@ export async function runStopWithQueuePause<TValue>(
         await queuedMessages.settleOwed()
       }
     } catch (error) {
-      report(ctx, 'owed settlement', error)
+      traceAgentSessionError({ step: 'stop-owed-settlement', sessionId: ctx.sessionId, error })
     }
     // Recorded only over a card it holds back — judged in its own transaction, which
     // still counts an owed return to waiting if that heal failed.
     await queuedMessages
       .recordPause('stopped')
-      .catch((error: unknown) => report(ctx, 'queue pause', error))
-  })
-}
-
-function report(ctx: AgentSessionTurnContext, step: string, error: unknown): void {
-  console.warn(`[agent-session] Stop's ${step} skipped:`, {
-    sessionId: ctx.sessionId,
-    error: error instanceof Error ? error.message : String(error)
+      .catch((error: unknown) =>
+        traceAgentSessionError({ step: 'stop-queue-pause', sessionId: ctx.sessionId, error })
+      )
   })
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-wiring.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-wiring.ts
index 2b193d5cb82f..fa015b4d1bbe 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-queued-wiring.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-queued-wiring.ts
@@ -32,8 +32,7 @@ export function wireStructuredAgentSessionQueuedMessages(
     flushStreamedEvents: (sessionId) => context().flushStreamedEvents(sessionId),
     conversationFence: (sessionId) =>
       structuredAgentSessionConversationFence(context().deps.store, sessionId),
-    wakeDelivery: (sessionId) => context().wakeDelivery(sessionId),
-    onError: (sessionId, error) => context().deps.onEventSinkError?.({ sessionId, error })
+    wakeDelivery: (sessionId) => context().wakeDelivery(sessionId)
   })
   return {
     drain,
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-recovered-turn-clock.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-recovered-turn-clock.test.ts
index f7d26c154f1f..7f2e9102c790 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-recovered-turn-clock.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-recovered-turn-clock.test.ts
@@ -118,7 +118,7 @@ async function sessionWithRunningTurn() {
 function settleDeadGeneration(
   journal: AgentSessionJournal,
   verdict: StructuredAgentSessionTurnVerdict
-): Promise<boolean> {
+) {
   return settleStructuredAgentSessionDeadGeneration({
     journal,
     sessionId: SESSION,
@@ -138,7 +138,7 @@ describe('a turn recovery settled after its host went away', () => {
     async (_label, verdict) => {
       const session = await sessionWithRunningTurn()
       session.recoverAt(RECOVERED)
-      expect(await settleDeadGeneration(session.journal, verdict)).toBe(true)
+      expect(await settleDeadGeneration(session.journal, verdict)).toEqual({ ok: true })
       session.publish()
 
       expect(session.summaries.at(-1)).toMatchObject({
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.test.ts
index d3c15de933c7..11f04d04fc96 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-resolved-append.test.ts
@@ -61,7 +61,7 @@ const appendSuffix =
 describe('resolved revisions', () => {
   it('reads the row as the journal holds it when each queued revision runs', async () => {
     const rows = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const bytes = estimateStructuredAgentSessionItemBytes(ROW, text('abc'))
     for (const suffix of ['a', 'b', 'c']) {
       expect(
@@ -81,7 +81,7 @@ describe('resolved revisions', () => {
 
   it('skips a revision that resolves to nothing', async () => {
     const rows = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     deferred.sink.tryReviseResolvedItem?.(1_000, () => null, {
       turnScope: AGENT_JOURNAL_THREAD_SCOPE
     })
@@ -93,7 +93,7 @@ describe('resolved revisions', () => {
 
   it('publishes a revision in the operation that writes it, within the same reservation', async () => {
     const rows = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const bytes = estimateStructuredAgentSessionItemBytes(ROW, text('a'))
     deferred.sink.tryReviseResolvedItemAndPublish?.(bytes, appendSuffix('a'), {
       turnScope: AGENT_JOURNAL_THREAD_SCOPE
@@ -114,7 +114,7 @@ describe('resolved revisions', () => {
 
   it('refuses a resolved write larger than the reservation it was admitted with', async () => {
     const rows = new Map<string, AgentJournalItemBody>()
-    const deferred = createDeferredStructuredAgentSessionEventSink()
+    const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
     const bytes = estimateStructuredAgentSessionItemBytes(ROW, text('a'))
     deferred.sink.tryReviseResolvedItem?.(
       bytes,
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-cap.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-cap.test.ts
index 9ded5b54d983..bdcc785df0df 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-cap.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-cap.test.ts
@@ -35,8 +35,7 @@ it('holds each slot from accept until handover or rejection, and frees it when t
       }
     },
     awaitSettlement: async () => ({ dispatchState: 'accepted' }),
-    note: async () => undefined,
-    onNoteFailed: () => undefined
+    note: async () => undefined
   })
   const sessions = Array.from({ length: 8 }, (_, index) => `session-${index}`)
   const outcomes = resumeStructuredAgentSessionsFromRestart(
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.test.ts
index 0fe36994cd7c..175f1fde1339 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.test.ts
@@ -1,4 +1,4 @@
-import { expect, it, vi } from 'vitest'
+import { beforeEach, expect, it, vi } from 'vitest'
 import { marker, SESSION } from './structured-agent-session-restart-resume-test-harness'
 import {
   AGENT_SESSION_RESTART_CONTINUATION_REFUSED_NOTE,
@@ -10,6 +10,15 @@ import {
   startStructuredAgentSessionContinuation,
   type StructuredAgentSessionContinuationDeps
 } from './structured-agent-session-restart-continuation'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
+
+beforeEach(() => {
+  vi.mocked(traceAgentSessionError).mockClear()
+})
 
 /** The whole continuation: handed over, then its verdict. */
 async function continueStructuredAgentSessionAfterRestart(
@@ -44,8 +53,7 @@ function dependencies(
           }
         : undefined
     ),
-    note: vi.fn(async () => undefined),
-    onNoteFailed: vi.fn()
+    note: vi.fn(async () => undefined)
   }
 }
 
@@ -61,6 +69,22 @@ it('reports an accepted continuation and records its note', async () => {
   expect(deps.note).toHaveBeenCalledOnce()
 })
 
+// Best effort, but never silent: a swallowed note is how this regressed unnoticed once already.
+it('reports a note it could not write without failing the continuation', async () => {
+  const deps = dependencies('accepted')
+  const failure = new Error('journal closed')
+  deps.note.mockRejectedValueOnce(failure)
+
+  await expect(
+    continueStructuredAgentSessionAfterRestart(deps, SESSION, marker(), 'operation-1')
+  ).resolves.toEqual({ sessionId: SESSION, outcome: 'continued' })
+  expect(traceAgentSessionError).toHaveBeenCalledExactlyOnceWith({
+    step: 'restart-continuation-note',
+    sessionId: SESSION,
+    error: failure
+  })
+})
+
 const UNCONFIRMED = [SESSION, AGENT_SESSION_RESTART_CONTINUATION_UNCONFIRMED_NOTE, 'warning']
 const REFUSED = [SESSION, AGENT_SESSION_RESTART_CONTINUATION_REFUSED_NOTE, 'error']
 const NOT_CONNECTED = [SESSION, AGENT_SESSION_RESTART_NOT_CONNECTED_NOTE, 'error']
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.ts
index 8038e90e1fc4..376f19618f96 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-continuation.ts
@@ -31,6 +31,7 @@ import {
 import { AgentSessionPreDispatchError } from './structured-agent-session-operation-settlement'
 import { restartContinuationEnvelope } from './structured-agent-session-restart-continuation-envelope'
 import type { AgentSessionResumeMarker } from '../../../shared/agent-session-resume-marker'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /**
  * All four dispatch states are preserved, never collapsed into transport success.
@@ -71,7 +72,6 @@ export type StructuredAgentSessionContinuationHost = {
     sessionId: string,
     clientMessageId: string
   ) => Promise<{ value: AgentSessionSendResult } | undefined>
-  onNoteFailed: (sessionId: string, error: unknown) => void
   now: () => number
   /** Whether the marker is still an offer. Asked at acceptance, inside the session lock, so the
    *  first message accepted since the restart decides: the user's, or this continuation. */
@@ -103,7 +103,6 @@ export function restartContinuationDeps(
       agentSessionSendSubmission(
         (await host.awaitSendHandedOver(sessionId, clientMessageId))?.value
       ),
-    onNoteFailed: host.onNoteFailed,
     note: restartNoteWriter(host)
   }
 }
@@ -183,11 +182,10 @@ export type StructuredAgentSessionContinuationDeps = {
     clientMessageId: string
   ) => Promise<ContinuationSubmission | undefined>
   /** Records a host-authored journal note: that this send was Orca's, not the user's, or that the
-   *  chat did not carry on. `tone` is a display hint older clients render as plain text. */
+   *  chat did not carry on. `tone` is a display hint older clients render as plain text. Best
+   *  effort, but a note that could not be written is reported: a swallowed append is how this
+   *  regressed unnoticed once already. */
   note: (sessionId: string, text: string, tone?: 'error' | 'warning') => Promise<void>
-  /** Reports a note that could not be written. The note is best effort, but its failure is not
-   *  allowed to be silent — a swallowed append is how this regressed unnoticed once already. */
-  onNoteFailed: (sessionId: string, error: unknown) => void
 }
 
 /** A continuation handed to its agent, or already decided. */
@@ -232,7 +230,7 @@ export async function startStructuredAgentSessionContinuation(
 }
 
 async function noteOutcome(
-  deps: Pick<StructuredAgentSessionContinuationDeps, 'note' | 'onNoteFailed'>,
+  deps: Pick<StructuredAgentSessionContinuationDeps, 'note'>,
   sessionId: string,
   result: StructuredAgentSessionContinuationOutcome
 ): Promise<void> {
@@ -242,7 +240,7 @@ async function noteOutcome(
     try {
       await deps.note(sessionId, AGENT_SESSION_RESTART_CONTINUATION_NOTE)
     } catch (error) {
-      deps.onNoteFailed(sessionId, error)
+      traceAgentSessionError({ step: 'restart-continuation-note', sessionId, error })
     }
   } else {
     await noteNotContinued(
@@ -260,7 +258,7 @@ async function noteOutcome(
 /** The chat itself carries the failure, so it survives the toast, a dismissed record and a restart,
  *  and the user's next message is what moves past it. */
 async function noteNotContinued(
-  deps: Pick<StructuredAgentSessionContinuationDeps, 'note' | 'onNoteFailed'>,
+  deps: Pick<StructuredAgentSessionContinuationDeps, 'note'>,
   sessionId: string,
   outcome: 'refused' | 'not-connected' | 'unconfirmed'
 ): Promise<void> {
@@ -275,7 +273,7 @@ async function noteNotContinued(
           'error'
         ))
   } catch (error) {
-    deps.onNoteFailed(sessionId, error)
+    traceAgentSessionError({ step: 'restart-continuation-note', sessionId, error })
   }
 }
 
@@ -295,7 +293,7 @@ async function sendContinuation(
       throw error
     }
     // Persistence can fail after dispatch; a thrown send is not proof of non-delivery.
-    console.warn('[structured-agent-session] restart continuation send failed')
+    traceAgentSessionError({ step: 'restart-continuation-send', sessionId, error })
     return null
   })
   if (!sent) {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-failure-ledger.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-failure-ledger.ts
index ee769b9e8c33..1ed489f7f09f 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-failure-ledger.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-failure-ledger.ts
@@ -31,6 +31,7 @@ import {
   type StructuredAgentSessionResumeOutcome
 } from './structured-agent-session-restart-resume-runner'
 import { RESTART_CONTINUATION_SUPERSEDED } from './structured-agent-session-restart-continuation'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 type FailureCapsule = Pick<
   AgentSessionRecoveryCapsule,
@@ -86,9 +87,9 @@ export function createStructuredAgentSessionRestartFailureLedger(deps: {
   const read = async (): Promise<AgentSessionResumeFailureRecord[]> => {
     try {
       return (await deps.capsule?.listFailed(deps.now())) ?? []
-    } catch {
+    } catch (error) {
       // Recovery is advisory; a malformed capsule must not make ordinary chat actions unusable.
-      console.warn('[structured-agent-session] reading recovery capsule failed')
+      traceAgentSessionError({ step: 'recovery-capsule-read', error })
       return []
     }
   }
@@ -175,23 +176,17 @@ export function createStructuredAgentSessionRestartFailureLedger(deps: {
     }
     await deps
       .enqueue(() => capsule.completeResume(operationId, completed, deps.now()))
-      .catch(() => {
-        console.warn('[structured-agent-session] restart offer completion failed')
-      })
+      .catch((error: unknown) => traceAgentSessionError({ step: 'restart-offer-complete', error }))
     // Filed before the rollback so a failure the user must act on is never reopened as an offer
     // that would silently re-run it.
     await deps
       .enqueue(() => capsule.failResume(operationId, failures, deps.now()))
-      .catch(() => {
-        console.warn('[structured-agent-session] restart failure record failed')
-      })
+      .catch((error: unknown) => traceAgentSessionError({ step: 'restart-failure-record', error }))
     // This only reopens rows still owned by this operation. Rows removed by completeResume stay
     // removed, even when the write of a later bookkeeping step fails.
     await deps
       .enqueue(() => capsule.rollbackResume(operationId, deps.now()))
-      .catch(() => {
-        console.warn('[structured-agent-session] restart offer rollback failed')
-      })
+      .catch((error: unknown) => traceAgentSessionError({ step: 'restart-offer-rollback', error }))
   }
 
   return {
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-records.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-records.ts
index f9530039cd4a..5f731d4a7736 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-records.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-records.ts
@@ -3,6 +3,7 @@
 
 import type { AgentSessionRecoveryCapsule } from '../../runtime/agent-session-recovery-capsule'
 import type { AgentSessionResumeMarker } from '../../../shared/agent-session-resume-marker'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionRestartOfferRecords = {
   /** Every pending offer. Read-only; nothing is spent. */
@@ -30,10 +31,10 @@ export function createStructuredAgentSessionRestartOfferRecords(deps: {
   const readMarkers = async (): Promise<AgentSessionResumeMarker[]> => {
     try {
       return (await deps.capsule?.list(deps.now())) ?? []
-    } catch {
+    } catch (error) {
       // Recovery is advisory. A malformed capsule must not make ordinary chat actions unusable;
       // the durable bytes stay untouched so an explicit dismissal can remove them.
-      console.warn('[structured-agent-session] reading recovery capsule failed')
+      traceAgentSessionError({ step: 'recovery-capsule-read', error })
       return []
     }
   }
@@ -68,9 +69,7 @@ export function createStructuredAgentSessionRestartOfferRecords(deps: {
       }))
       void deps
         .enqueue(() => capsule.forgetSuperseded(gone, deps.now()))
-        .catch(() => {
-          console.warn('[structured-agent-session] pruning superseded restart offers failed')
-        })
+        .catch((error: unknown) => traceAgentSessionError({ step: 'restart-offer-prune', error }))
     }
   }
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-withdrawal.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-withdrawal.ts
index 76d8006d9a1a..aa3007ae7ba7 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-withdrawal.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-offer-withdrawal.ts
@@ -13,6 +13,7 @@ import type { AgentSessionResumeMarker } from '../../../shared/agent-session-res
 import { isQueuedAgentJournalSubmission } from '../../../shared/agent-session-queued-submission'
 import type { StructuredAgentSessionHostSession } from './structured-agent-session-host-types'
 import { isRestartContinuationOf } from './structured-agent-session-restart-continuation-envelope'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionRestartOfferWithdrawal = ReturnType<
   typeof createStructuredAgentSessionRestartOfferWithdrawal
@@ -84,9 +85,9 @@ export function createStructuredAgentSessionRestartOfferWithdrawal(deps: {
             startedFor === undefined ? false : isRestartContinuationOf(marker, startedFor)
           )
         )
-        .catch(() => {
-          console.warn('[structured-agent-session] withdrawing a restart offer failed')
-        })
+        .catch((error: unknown) =>
+          traceAgentSessionError({ step: 'restart-offer-withdraw', sessionId, error })
+        )
     }
   }
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-ownership.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-ownership.test.ts
index 59ff6958d53d..79d39c4a194f 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-ownership.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-ownership.test.ts
@@ -69,7 +69,9 @@ it('reports a failed attribution note without an installed error sink or private
     const result = await host.restartResume.continueAfterRestart([SESSION], 'modal')
     expect(result.continued).toMatchObject([{ outcome: 'continued' }])
     expect(warning).toHaveBeenCalledExactlyOnceWith(
-      '[structured-agent-session] restart continuation attribution failed'
+      '[agent-session] restart-continuation-note failed',
+      { sessionId: SESSION },
+      'Error'
     )
   } finally {
     write.mockRestore()
@@ -319,7 +321,8 @@ it('keeps concurrent recovery reads independent and non-destructive', async () =
 
 it('fails closed on corrupt recovery storage while an ordinary send still works', async () => {
   const { host, root, dispatch } = await interruptedRestart()
-  await writeFile(join(root, AGENT_SESSION_RECOVERY_CAPSULE_FILE), '{')
+  // Not JSON: its SyntaxError quotes the start of the file, which no log may repeat.
+  await writeFile(join(root, AGENT_SESSION_RECOVERY_CAPSULE_FILE), 'my private prompt text')
   const warning = vi.spyOn(console, 'warn').mockImplementation(() => {})
   expect(await host.restartResume.list()).toEqual([])
   expect(await host.restartResume.continueAfterRestart([SESSION], 'modal')).toEqual({
@@ -335,9 +338,14 @@ it('fails closed on corrupt recovery storage while an ordinary send still works'
   await vi.waitFor(() => expect(dispatch).toHaveBeenCalledTimes(1))
   // list; the action's read of offers and of failures; the post-action refresh of both. The send
   // cannot withdraw an offer it cannot read either, and says so.
-  const withdrawing = '[structured-agent-session] withdrawing a restart offer failed'
-  await vi.waitFor(() => expect(warning).toHaveBeenLastCalledWith(withdrawing))
-  expect(warning.mock.calls.filter(([message]) => message !== withdrawing)).toHaveLength(5)
+  const withdrawing = '[agent-session] restart-offer-withdraw failed'
+  await vi.waitFor(() =>
+    expect(warning).toHaveBeenLastCalledWith(withdrawing, { sessionId: SESSION }, 'SyntaxError')
+  )
+  expect(warning.mock.calls.filter(([message]) => message !== withdrawing)).toEqual(
+    Array.from({ length: 5 }, () => [expect.any(String), {}, 'SyntaxError'])
+  )
+  expect(warning.mock.calls.flat().map(String).join(' ')).not.toContain('private')
   warning.mockRestore()
 })
 
@@ -451,7 +459,9 @@ it('logs teardown capsule publication failure and still releases the provider',
     'agent_session_ownership_unknown'
   )
   expect(warning).toHaveBeenCalledWith(
-    '[structured-agent-session] recording recovery capsule failed'
+    '[agent-session] recovery-capsule-record failed',
+    {},
+    expect.any(String)
   )
   expect(warning.mock.calls.flat().map(String).join(' ')).not.toContain(previous.root)
   expect(previous.store.getRecord(SESSION)?.lease.claimStatus).toBe('released')
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-host.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-host.ts
index d053caf006b2..efd15f6d2bc8 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-host.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-host.ts
@@ -44,6 +44,7 @@ import {
 import type { StructuredAgentSessionRestartResumeSurfaces } from './structured-agent-session-restart-resume-wiring'
 import { createStructuredAgentSessionRestartWitnesses } from './structured-agent-session-restart-witnesses'
 import { structuredAgentSessionConversationFence } from './structured-agent-session-provider-child'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 type LiveSession = StructuredAgentSessionRestartOfferSession
 
@@ -205,9 +206,9 @@ export function createStructuredAgentSessionRestartResume(
       if (deps.recoveryCapsule) {
         await enqueueRecoveryOperation(() =>
           deps.recoveryCapsule!.rollbackResume(operationId, surfaces.now())
-        ).catch(() => {
-          console.warn('[structured-agent-session] restart offer rollback failed')
-        })
+        ).catch((rollbackError: unknown) =>
+          traceAgentSessionError({ step: 'restart-offer-rollback', error: rollbackError })
+        )
       }
       throw error
     }
@@ -279,8 +280,8 @@ export function createStructuredAgentSessionRestartResume(
     try {
       remainingCandidates = await list()
       remainingFailures = await failures.list()
-    } catch {
-      console.warn('[structured-agent-session] restart offer refresh failed after action')
+    } catch (error) {
+      traceAgentSessionError({ step: 'restart-offer-refresh', error })
     }
     return {
       resumed,
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-wiring.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-wiring.ts
index 4004502e4081..7f05467be545 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-wiring.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-resume-wiring.ts
@@ -29,7 +29,6 @@ export type StructuredAgentSessionRestartResumeSurfaces = {
     sessionId: string,
     clientMessageId: string
   ) => Promise<{ value: AgentSessionSendResult } | undefined>
-  onNoteFailed: (sessionId: string, error: unknown) => void
   now: () => number
 }
 
@@ -76,8 +75,6 @@ export function structuredAgentSessionRestartResumeSurfaces(
         until: 'handed-over',
         budgetMs: MAX_TIMER_DELAY_MS
       }),
-    onNoteFailed: () =>
-      console.warn('[structured-agent-session] restart continuation attribution failed'),
     now
   }
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-teardown.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-teardown.test.ts
index 2ea9e6f57b77..3ae9e98149a2 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restart-teardown.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restart-teardown.test.ts
@@ -23,10 +23,14 @@ it.each(['beginTeardown', 'captureBeforeStop', 'recordMarkers'] as const)(
       await expect(host.flushAllStreamedEvents()).resolves.toBeUndefined()
       expect(operation).toHaveBeenCalledOnce()
       expect(warning).toHaveBeenCalledExactlyOnceWith(
-        {
-          beginTeardown: '[structured-agent-session] capturing recovery witnesses failed',
-          captureBeforeStop: '[structured-agent-session] capturing recovery witness failed',
-          recordMarkers: '[structured-agent-session] recording recovery capsule failed'
+        ...{
+          beginTeardown: ['[agent-session] recovery-witness-begin failed', {}, 'Error'],
+          captureBeforeStop: [
+            '[agent-session] recovery-witness-capture failed',
+            { sessionId: SESSION },
+            'Error'
+          ],
+          recordMarkers: ['[agent-session] recovery-capsule-record failed', {}, 'Error']
         }[method]
       )
       expect(warning.mock.calls.flat().map(String).join(' ')).not.toContain(failure.message)
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-restore-without-import.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-restore-without-import.test.ts
index 226e6536c9c1..0d519c56018a 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-restore-without-import.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-restore-without-import.test.ts
@@ -216,7 +216,6 @@ type LifetimeHost = Parameters<typeof createStructuredAgentSessionConversationLi
 function conversations(): StructuredAgentSessionConversations {
   return new StructuredAgentSessionConversations({
     deliver: () => undefined,
-    onDeliveryError: () => undefined,
     now: () => clock
   })
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.test.ts
index fbe81be21ac1..f25ae7555520 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.test.ts
@@ -25,6 +25,11 @@ import {
   resetHostTestOperationIds
 } from './structured-agent-session-host-test-data'
 import { openTestJournalHostDatabase } from '../agent-session-journal/journal-host-database-test-support'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const CALLER = { callerKey: 'client-1' }
 
@@ -39,12 +44,11 @@ let host: StructuredAgentSessionHost
 let acquire: Mock<StructuredAgentSessionAdapter['acquire']>
 let spawnChild: StructuredAgentSessionAdapter['acquire']
 let dispatch: Mock<StructuredAgentSessionAdapter['dispatch']>
-let hostErrors: unknown[]
 
 beforeEach(async () => {
   root = await mkdtemp(join(tmpdir(), 'orca-send-recovery-'))
   resetHostTestOperationIds()
-  hostErrors = []
+  vi.mocked(traceAgentSessionError).mockClear()
   let generation = 0
   spawnChild = async ({ fence, spawnToken }) => ({
     process: { hostId: 'local', pid: 4242, processStartTimeMs: 1_700_000_000_000, spawnToken },
@@ -84,8 +88,7 @@ beforeEach(async () => {
     journalDatabase: openTestJournalHostDatabase(root),
     claimKeyId: 'key-1',
     mintSpawnToken: () => `spawn-${acquire.mock.calls.length}`,
-    now: () => NOW,
-    onEventSinkError: ({ error }) => hostErrors.push(error)
+    now: () => NOW
   })
   expect(await host.attach(CALLER, hostTestAttachParams(null))).toMatchObject({ ok: true })
 })
@@ -407,7 +410,6 @@ describe('a send with no live owner', () => {
     acquire.mockRejectedValue(
       new CodexAppServerRequestError('thread/resume', -32600, `thread/resume failed: ${said}`, said)
     )
-    const warn = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
 
     const id = await accept(sendParams('after the thread went away'))
 
@@ -426,11 +428,11 @@ describe('a send with no live owner', () => {
       "Codex couldn't restart. Send your message to try again."
     ])
     // Orca's own text is logged once where the start failed.
-    expect(warn).toHaveBeenCalledWith(
-      '[agent-session] provider start failed:',
-      expect.objectContaining({ message: `thread/resume failed: ${said}` })
-    )
-    warn.mockRestore()
+    expect(traceAgentSessionError).toHaveBeenCalledWith({
+      step: 'provider-start',
+      sessionId: SESSION,
+      error: expect.objectContaining({ message: `thread/resume failed: ${said}` })
+    })
   })
 
   it('restarts again for a Retry under a new id, and replays a resend of the same id', async () => {
@@ -537,9 +539,11 @@ describe('a send with no live owner', () => {
       reason: "Orca ran into a problem, so this didn't go through. Try again.",
       rejection: { kind: 'hostFault' }
     })
-    expect(hostErrors).toContainEqual(
-      expect.objectContaining({ message: 'spawn-token mint failed' })
-    )
+    expect(traceAgentSessionError).toHaveBeenCalledWith({
+      step: 'delivery-loop',
+      sessionId: SESSION,
+      error: expect.objectContaining({ message: 'spawn-token mint failed' })
+    })
     expect(await errorStatuses()).toHaveLength(1)
   })
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.ts
index be29089991bd..a3811b210f66 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-send-preparation.ts
@@ -24,6 +24,7 @@ import {
 } from './structured-agent-session-mutation-admission'
 import { rewindRefusal } from './structured-rewind-refusal'
 import type { StructuredAgentSessionMutationContext } from './structured-agent-session-host-mutations'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 /** Why the record refuses any send right now, whoever owns it; null when a send may run. */
 export function structuredAgentSessionSendBlock(
@@ -64,7 +65,7 @@ export async function openConversationForWrite(
     }
     return { ok: false, refusal: AGENT_SESSION_NOT_ATTACHED }
   } catch (error) {
-    console.warn('[agent-session] opening the conversation for a write failed:', error)
+    traceAgentSessionError({ step: 'journal-open-write', sessionId: envelope.sessionId, error })
     return { ok: false, refusal: journalOpenRefusal(error) }
   }
 }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.test.ts
index ad23177bdd3a..6e539abefc61 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.test.ts
@@ -540,7 +540,7 @@ describe('StructuredAgentSessionStatusFeed', () => {
       const { feed } = feedFor(new Map([[SESSION, { journal }]]), null, (summary) =>
         seen.push(summary.status)
       )
-      const deferred = createDeferredStructuredAgentSessionEventSink()
+      const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
       if (agent === 'claude') {
         const translator = createClaudeJournalTranslator({ sink: deferred.sink })
         translator.handle({
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.ts
index 22a61a006bb6..0fe3838c95a4 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-status-feed.ts
@@ -31,6 +31,7 @@ import {
   StructuredAgentSessionStatusOwnership,
   type StructuredAgentSessionStatusSink
 } from './structured-agent-session-status-ownership'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export type { StructuredAgentSessionStatusSink } from './structured-agent-session-status-ownership'
 
@@ -182,7 +183,7 @@ export class StructuredAgentSessionStatusFeed {
     try {
       this.ownership.forget(sessionId)
     } catch (error) {
-      console.warn('[structured-session-status] status sink forget failed', error)
+      traceAgentSessionError({ step: 'status-forget', sessionId, error })
     }
   }
 
@@ -254,7 +255,7 @@ export class StructuredAgentSessionStatusFeed {
       this.deps.onStatusChanged?.(summary, { replay: options?.replay === true })
     } catch (error) {
       // An observer must never cost the subscribers their status event.
-      console.warn('[structured-session-status] status observer failed', error)
+      traceAgentSessionError({ step: 'status-observer', sessionId, error })
     }
   }
 
@@ -306,7 +307,7 @@ export class StructuredAgentSessionStatusFeed {
     try {
       this.ownership.publishChildWork(sessionId, evidence, session.params.provider)
     } catch (error) {
-      console.warn('[structured-session-status] child work publish failed', error)
+      traceAgentSessionError({ step: 'child-work-publish', sessionId, error })
     }
   }
 
@@ -353,7 +354,7 @@ export class StructuredAgentSessionStatusFeed {
     try {
       this.ownership.publish(summary, location)
     } catch (error) {
-      console.warn('[structured-session-status] status sink publish failed', error)
+      traceAgentSessionError({ step: 'status-publish', sessionId: summary.sessionId, error })
     }
   }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-subagent-recency.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-subagent-recency.test.ts
index 20b5038f1734..ff6396b7f5cb 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-subagent-recency.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-subagent-recency.test.ts
@@ -83,7 +83,7 @@ async function openSession() {
   })
   const events: AgentSessionStatusEvent[] = []
   feed.subscribe({ id: 'list-1', emit: (event) => events.push(event) })
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   deferred.bind({ journal, fence: 1, publish: () => feed.publish(SESSION, journal) })
   const drain = async (): Promise<void> => {
     expect(await deferred.drained()).toEqual({ ok: true })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts
index a06c70bf30ad..50d6f3f0c2b5 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-surface-lifetime.test.ts
@@ -41,6 +41,11 @@ import {
 import { agentSessionFailureFact } from '../../../shared/agent-session-failure'
 import { agentSessionFailureWords } from '../../../shared/agent-session-failure-words'
 import { openTestJournalHostDatabase } from '../agent-session-journal/journal-host-database-test-support'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const UNEXPECTED_PROVIDER_EXIT_OUTCOME =
   'Codex stopped while this response was in progress. You can continue in this conversation.'
@@ -83,7 +88,6 @@ function openHost(
     mintSpawnToken: () => `spawn-${acquire.mock.calls.length}`,
     idleSweep: { intervalMs: SWEEP_MS, idleMs: IDLE_MS },
     now: () => clock,
-    onEventSinkError: ({ error }) => hostErrors.push(error),
     statusSink,
     ...(probeOwner ? { probeOwner } : {})
   })
@@ -206,6 +210,9 @@ beforeEach(async () => {
   resetHostTestOperationIds()
   sink = null
   hostErrors = []
+  vi.mocked(traceAgentSessionError).mockImplementation(({ error }) => {
+    hostErrors.push(error)
+  })
   clock = NOW
   statusSink = { publish: vi.fn(), forget: vi.fn() }
   let generation = 0
@@ -332,6 +339,32 @@ describe('a chat that closes', () => {
     expect(closeSession).toHaveBeenCalledOnce()
   })
 
+  it('records a failed stop-time settlement once, and still throws it as the cause', async () => {
+    await attach()
+    emitTurnLifecycle('running', 1)
+    await host.flushStreamedEvents(SESSION)
+    const refusal = new Error('settlement unavailable')
+    const refusing = vi
+      .spyOn(host['sessions'].get(SESSION)!.journal, 'appendLifecycleBatch')
+      .mockRejectedValue(refusal)
+    vi.mocked(traceAgentSessionError).mockClear()
+
+    const thrown: unknown = await host.close(SESSION).catch((error: unknown) => error)
+
+    expect(thrown).toMatchObject({ step: 'settle-dead-generation' })
+    const wrapper = thrown instanceof Error ? thrown.cause : undefined
+    expect(wrapper).toMatchObject({ message: 'dead generation work settlement failed' })
+    expect(wrapper instanceof Error ? wrapper.cause : undefined).toBe(refusal)
+    expect(
+      vi
+        .mocked(traceAgentSessionError)
+        .mock.calls.filter(([report]) => report.step === 'dead-generation-settlement')
+    ).toEqual([[{ step: 'dead-generation-settlement', sessionId: SESSION, error: refusal }]])
+
+    refusing.mockRestore()
+    await expect(host.close(SESSION)).resolves.toBeUndefined()
+  })
+
   it('settles and releases on the retry when a step after the child stopped aborts', async () => {
     await attach()
     dispatch.mockResolvedValueOnce({ state: 'admitted' })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-turns.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-turns.ts
index 13aa9d72aea0..b262d6016f2d 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-turns.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-turns.ts
@@ -23,6 +23,7 @@ import {
 } from '../../../shared/agent-session-wire'
 import { isAgentSessionRefusalError } from '../../../shared/agent-session-wire-refusals'
 import { DISPATCH_DOUBT_PERSISTENCE_FAILED } from '../agent-session-journal/journal-dispatch-doubt-reasons'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 import type { AgentSessionJournal } from '../agent-session-journal/journal-store'
 import type {
   AgentSessionDispatchOutcome,
@@ -238,8 +239,13 @@ export async function handOverSubmission(
         reason: DISPATCH_DOUBT_PERSISTENCE_FAILED,
         fence: ctx.fence
       })
-    } catch {
-      // Nothing further to record; the pending row is settled on the next open.
+    } catch (doubtError) {
+      // The pending row is settled on the next open.
+      traceAgentSessionError({
+        step: 'dispatch-doubt-record',
+        sessionId: ctx.sessionId,
+        error: doubtError
+      })
     }
     throw error
   }
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.test.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.test.ts
index 2cb38a466345..9312f362a1ff 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.test.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.test.ts
@@ -13,6 +13,11 @@ import {
   type StructuredAgentSessionUnexpectedExitContext,
   type StructuredAgentSessionUnexpectedExitSession
 } from './structured-agent-session-unexpected-exit'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
+
+vi.mock('../../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const exitOutcome = (agent: string): string =>
   `${agent} stopped while this response was in progress. You can continue in this conversation.`
@@ -406,7 +411,7 @@ describe('provider-exit settlement', () => {
         })
       }
     }
-    const release = vi.fn()
+    vi.mocked(traceAgentSessionError).mockClear()
     const publishFence = vi.fn()
     const event = {
       type: 'ended' as const,
@@ -423,13 +428,15 @@ describe('provider-exit settlement', () => {
       flushLifecycle: async () => ({ ok: false, error: new Error('sink failed') }),
       publishFence,
       serialize: async (_sessionId, task) => task(),
-      now: () => 1,
-      onBarrierError: release
+      now: () => 1
     }
     await settleUnexpectedStructuredAgentSessionExit(context, event)
 
     expect(session.child).toBeNull()
     expect(publishFence).toHaveBeenCalledTimes(1)
-    expect(release).toHaveBeenCalledTimes(2)
+    expect(vi.mocked(traceAgentSessionError).mock.calls.map(([report]) => report.step)).toEqual([
+      'provider-exit-barrier',
+      'dead-generation-settlement'
+    ])
   })
 })
diff --git a/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.ts b/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.ts
index 3f758f81607b..f625889ea5e7 100644
--- a/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.ts
+++ b/src/main/native-chat/agent-session-wire/structured-agent-session-unexpected-exit.ts
@@ -14,9 +14,14 @@ import {
   MAX_UNEXPECTED_EXIT_REASON_CHARS,
   settleStructuredAgentSessionDeadGeneration,
   type DeadGenerationJournal,
+  type StructuredAgentSessionDeadGenerationSettlement,
   unfinishedStructuredAgentSessionWorkWasInterrupted
 } from './structured-agent-session-dead-generation-settlement'
 import type { StructuredAgentSessionTurnVerdict } from './structured-agent-session-stale-turn-verdict'
+import {
+  traceAgentSessionError,
+  type AgentSessionErrorStep
+} from '../../observability/agent-session-error-trace'
 
 type UnexpectedExitLifecycleEvent = StructuredAgentSessionEndedEvent & {
   cause: 'unexpected-exit'
@@ -37,7 +42,6 @@ export type StructuredAgentSessionUnexpectedExitContext<
   publishStatus?: (sessionId: string) => void
   serialize: <T>(sessionId: string, task: () => Promise<T>) => Promise<T>
   now: () => number
-  onBarrierError?: (sessionId: string, error: unknown) => void
 }
 
 export async function settleUnexpectedStructuredAgentSessionExit<
@@ -87,19 +91,20 @@ export async function settleUnexpectedStructuredAgentSessionExit<
       return
     }
 
+    const reportExitFailure = (step: AgentSessionErrorStep, error: unknown): void =>
+      traceAgentSessionError({ step, sessionId: unexpectedEvent.sessionId, error })
     const stableSettlementId = providerExitSettlementId(unexpectedEvent)
     const unfinishedWork = captureUnfinishedStructuredAgentSessionWork(session.journal)
     try {
       try {
         const barrier = await context.flushLifecycle(unexpectedEvent.sessionId)
         if (!barrier.ok) {
-          context.onBarrierError?.(unexpectedEvent.sessionId, barrier.error)
+          reportExitFailure('provider-exit-barrier', barrier.error)
         }
       } catch (error) {
-        context.onBarrierError?.(unexpectedEvent.sessionId, error)
+        reportExitFailure('provider-exit-barrier', error)
       }
       await retryUnexpectedExitSettlement({
-        context,
         event: unexpectedEvent,
         journal: session.journal,
         fence: child.fence,
@@ -136,7 +141,7 @@ export async function settleUnexpectedStructuredAgentSessionExit<
           exitReason: unexpectedEvent.reason.slice(0, MAX_UNEXPECTED_EXIT_REASON_CHARS)
         })
       } catch (error) {
-        context.onBarrierError?.(unexpectedEvent.sessionId, error)
+        reportExitFailure('provider-exit-lease-release', error)
       } finally {
         endChild()
         if (released) {
@@ -148,7 +153,6 @@ export async function settleUnexpectedStructuredAgentSessionExit<
 }
 
 async function retryUnexpectedExitSettlement(input: {
-  context: Pick<StructuredAgentSessionUnexpectedExitContext, 'onBarrierError'>
   event: UnexpectedExitLifecycleEvent
   journal: DeadGenerationJournal
   fence: number
@@ -157,7 +161,7 @@ async function retryUnexpectedExitSettlement(input: {
   exitedDuringStartup: boolean
   failureTextContext: AgentSessionFailureWordsContext
   showUnexpectedExitOutcome?: boolean
-}): Promise<boolean> {
+}): Promise<StructuredAgentSessionDeadGenerationSettlement> {
   return settleStructuredAgentSessionDeadGeneration({
     journal: input.journal,
     sessionId: input.event.sessionId,
@@ -170,8 +174,7 @@ async function retryUnexpectedExitSettlement(input: {
     failureTextContext: input.failureTextContext,
     ...(input.exitedDuringStartup
       ? { exitedDuringStartup: { generation: input.event.acquisitionGeneration } }
-      : {}),
-    onError: input.context.onBarrierError
+      : {})
   })
 }
 
diff --git a/src/main/native-chat/agent-session-wire/structured-rewind-recovery.ts b/src/main/native-chat/agent-session-wire/structured-rewind-recovery.ts
index b572e51e5f39..0050f6bb6628 100644
--- a/src/main/native-chat/agent-session-wire/structured-rewind-recovery.ts
+++ b/src/main/native-chat/agent-session-wire/structured-rewind-recovery.ts
@@ -13,6 +13,7 @@ import type { AgentSessionJournal } from '../agent-session-journal/journal-store
 import type { StructuredAgentSessionAdapter } from './structured-agent-session-adapter'
 import { AGENT_SESSION_HISTORY_MAX_PAGE_BYTES } from './agent-session-history-page-bounds'
 import { rewindRefusal } from './structured-rewind-refusal'
+import { traceAgentSessionError } from '../../observability/agent-session-error-trace'
 
 export function persistRewindRecord(
   store: AgentSessionRecordStore,
@@ -52,10 +53,11 @@ async function settleUnsupportedClaudeRewind(
       outcome: { status: 'failed', code: refusal.code, rewindReason: 'unsupported' }
     })
   } catch (error) {
-    console.warn('[structured-rewind] pending Claude rewind was not settled:', {
+    traceAgentSessionError({
+      step: 'rewind-recovery',
       sessionId,
-      operationId: rewind.operationId,
-      error
+      error,
+      detail: { operationId: rewind.operationId }
     })
   }
 }
diff --git a/src/main/observability/agent-session-error-trace-ratchet.test.ts b/src/main/observability/agent-session-error-trace-ratchet.test.ts
new file mode 100644
index 000000000000..348904a50c32
--- /dev/null
+++ b/src/main/observability/agent-session-error-trace-ratchet.test.ts
@@ -0,0 +1,130 @@
+import { readFileSync, readdirSync, statSync } from 'node:fs'
+import { basename, join, relative, resolve } from 'node:path'
+import { describe, expect, it } from 'vitest'
+
+/**
+ * Structured chat session code reports every background error through
+ * `traceAgentSessionError`. The two shapes it replaced both lost failures in a packaged
+ * build: a `console` line (the main process owns no console there) and an optional `on*Error?` sink
+ * that no caller had to supply. A catch site reports its own step; a callback it takes carries
+ * behavior and is required.
+ */
+const REPO_ROOT = resolve(__dirname, '..', '..', '..')
+
+/** Directories scanned whole. */
+const SCANNED_TREES = [
+  'src/main/native-chat/agent-session-wire',
+  'src/main/native-chat/agent-session-journal',
+  'src/main/native-chat/agent-model-catalog'
+]
+/** Directories whose files with one of these prefixes are scanned. */
+const SCANNED_PREFIXED: readonly { dir: string; prefix: string }[] = [
+  { dir: 'src/main/native-chat', prefix: 'structured-agent-session-' },
+  { dir: 'src/main/runtime', prefix: 'structured-agent-session-' },
+  { dir: 'src/main/runtime/rpc/methods', prefix: 'structured-agent-session-' },
+  { dir: 'src/main/claude', prefix: 'claude-structured-' }
+]
+
+const CONSOLE_FAILURE =
+  /\bconsole\s*(?:\.\s*(?:warn|error)|\[\s*(['"`])(?:warn|error)\1\s*\])(?![\w$])/
+const OPTIONAL_ERROR_SINK = /\b(on\w*(?:Error|Failure|Failed))\s*\?\s*[:(]/g
+
+/** Optional because they carry behavior only some callers want, never because a caller may skip
+ *  reporting: each failure is also reported, or handled, where it happens. */
+const BEHAVIORAL_OPTIONAL_CALLBACKS = new Set([
+  // Hands agent-start the acquisition error its refusal is built from; attach-flow reports it too.
+  'onAcquisitionFailed',
+  // Rejects the start or ends the child; a translator built outside an acquisition has neither.
+  'onBackgroundTaskJournalFailure'
+])
+
+function isProductionSource(path: string): boolean {
+  return /\.tsx?$/.test(path) && !/\.(?:test|spec)\.tsx?$/.test(path)
+}
+
+function collectTree(root: string): string[] {
+  return readdirSync(root).flatMap((entry) => {
+    const full = join(root, entry)
+    return statSync(full).isDirectory() ? collectTree(full) : [full]
+  })
+}
+
+function scannedFiles(): string[] {
+  const trees = SCANNED_TREES.flatMap((dir) => collectTree(join(REPO_ROOT, dir)))
+  const prefixed = SCANNED_PREFIXED.flatMap(({ dir, prefix }) =>
+    readdirSync(join(REPO_ROOT, dir))
+      .filter((entry) => entry.startsWith(prefix))
+      .map((entry) => join(REPO_ROOT, dir, entry))
+      .filter((full) => statSync(full).isFile())
+  )
+  return [...trees, ...prefixed].filter((full) => isProductionSource(basename(full)))
+}
+
+/** Drop comment-only lines so prose about the old idiom is not an offender. */
+function codeText(contents: string): string {
+  return contents
+    .split('\n')
+    .filter((line) => !/^\s*(?:\/\/|\/\*|\*)/.test(line))
+    .join('\n')
+}
+
+function repoPath(file: string): string {
+  return relative(REPO_ROOT, file).split('\\').join('/')
+}
+
+function consoleOffenders(files: readonly string[]): string[] {
+  return files
+    .filter((file) => CONSOLE_FAILURE.test(codeText(readFileSync(file, 'utf8'))))
+    .map(repoPath)
+}
+
+function optionalSinks(text: string): string[] {
+  return [...text.matchAll(OPTIONAL_ERROR_SINK)]
+    .map((match) => match[1])
+    .filter((name) => !BEHAVIORAL_OPTIONAL_CALLBACKS.has(name))
+}
+
+function optionalSinkOffenders(files: readonly string[]): string[] {
+  return files.flatMap((file) =>
+    optionalSinks(codeText(readFileSync(file, 'utf8'))).map((name) => `${repoPath(file)}: ${name}`)
+  )
+}
+
+describe('structured chat session background error reporting', () => {
+  const files = scannedFiles()
+
+  it('scans a plausible number of files', () => {
+    // A moved directory would make the guard silently vacuous.
+    expect(files.length).toBeGreaterThan(250)
+  })
+
+  it('reports failures through the reporter, never the console', () => {
+    expect(
+      consoleOffenders(files),
+      'Call traceAgentSessionError from src/main/observability/agent-session-error-trace instead.'
+    ).toEqual([])
+  })
+
+  it('declares no optional error sink', () => {
+    expect(
+      optionalSinkOffenders(files),
+      'Report at the catch site; a callback that carries behavior is required.'
+    ).toEqual([])
+  })
+
+  it('catches both shapes', () => {
+    expect(CONSOLE_FAILURE.test("console.warn('x', error)")).toBe(true)
+    expect(CONSOLE_FAILURE.test("console['error']('x')")).toBe(true)
+    expect(CONSOLE_FAILURE.test('const warn = console.warn')).toBe(true)
+    expect(CONSOLE_FAILURE.test("console.info('x')")).toBe(false)
+    expect(CONSOLE_FAILURE.test('console.warning')).toBe(false)
+    expect(optionalSinks('  onError?: (error: unknown) => void')).toEqual(['onError'])
+    expect(optionalSinks('  onEventSinkError?: (input) => void')).toEqual(['onEventSinkError'])
+    expect(optionalSinks('  onFailure?: (error: unknown) => void')).toEqual(['onFailure'])
+    expect(optionalSinks('  onNoteFailed?(error: unknown): void')).toEqual(['onNoteFailed'])
+    expect(optionalSinks('  onAcquisitionFailed?: (error: unknown) => void')).toEqual([])
+    expect(optionalSinks('  onError: (error: unknown) => void')).toEqual([])
+    expect(optionalSinks('  deps.onError?.(error)')).toEqual([])
+    expect(optionalSinks('  const x = onFailure ? a : b')).toEqual([])
+  })
+})
diff --git a/src/main/observability/agent-session-error-trace.test.ts b/src/main/observability/agent-session-error-trace.test.ts
new file mode 100644
index 000000000000..bc7853b3f43d
--- /dev/null
+++ b/src/main/observability/agent-session-error-trace.test.ts
@@ -0,0 +1,256 @@
+import { mkdtempSync, readFileSync, rmSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import {
+  AGENT_SESSION_ERROR_STEPS,
+  traceAgentSessionError,
+  type AgentSessionErrorStep
+} from './agent-session-error-trace'
+import { createLocalFileSink } from './local-file-sink'
+import { setActiveSink } from './tracer'
+
+let dir: string
+
+beforeEach(() => {
+  dir = mkdtempSync(join(tmpdir(), 'orca-agent-session-failure-'))
+})
+
+afterEach(() => {
+  setActiveSink(null)
+  vi.restoreAllMocks()
+  rmSync(dir, { recursive: true, force: true })
+})
+
+function isRecord(value: unknown): value is Record<string, unknown> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value)
+}
+
+function readTrace(filePath: string): Record<string, unknown>[] {
+  return readFileSync(filePath, 'utf8')
+    .split('\n')
+    .filter(Boolean)
+    .map((line) => {
+      const record: unknown = JSON.parse(line)
+      if (!isRecord(record)) {
+        throw new Error(`trace line is not an object: ${line}`)
+      }
+      return record
+    })
+}
+
+function failureCause(record: Record<string, unknown> | undefined): string {
+  const exit = record?.exit
+  if (!isRecord(exit) || typeof exit.cause !== 'string') {
+    throw new Error('trace record has no failure cause')
+  }
+  return exit.cause
+}
+
+describe('traceAgentSessionError', () => {
+  it('writes a failed span with its step and session to the trace file', () => {
+    vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const filePath = join(dir, 'logs', 'main.trace.ndjson')
+    const sink = createLocalFileSink({ filePath, flushBufferThreshold: 1 })
+    setActiveSink(sink)
+
+    traceAgentSessionError({
+      step: 'lease-renewal',
+      sessionId: 'session-1',
+      error: new Error('dead generation work settlement failed', {
+        cause: new AggregateError([new Error('journal write refused')], 'settle failed')
+      }),
+      detail: { fence: 3 }
+    })
+    sink.flush()
+    sink.close()
+
+    const records = readTrace(filePath)
+    expect(records).toEqual([
+      expect.objectContaining({
+        type: 'effect-span',
+        name: 'agent-session.failure',
+        attributes: { step: 'lease-renewal', sessionId: 'session-1', fence: 3 },
+        exit: { _tag: 'Failure', cause: expect.any(String) }
+      })
+    ])
+    const cause = failureCause(records[0])
+    // The wrapper alone names only the step; the chain is what says why.
+    expect(cause).toContain('dead generation work settlement failed')
+    expect(cause).toContain('[cause] AggregateError: settle failed')
+    expect(cause).toContain('[aggregated] Error: journal write refused')
+  })
+
+  it('records a non-Error failure as its text', () => {
+    vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const filePath = join(dir, 'main.trace.ndjson')
+    const sink = createLocalFileSink({ filePath, flushBufferThreshold: 1 })
+    setActiveSink(sink)
+
+    traceAgentSessionError({ step: 'journal-rollback', error: 'database is locked' })
+    sink.flush()
+    sink.close()
+
+    expect(readTrace(filePath)).toEqual([
+      expect.objectContaining({
+        attributes: { step: 'journal-rollback' },
+        exit: { _tag: 'Failure', cause: 'database is locked' }
+      })
+    ])
+  })
+
+  it('keeps a SQLite or journal code the message leaves out', () => {
+    vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const filePath = join(dir, 'main.trace.ndjson')
+    const sink = createLocalFileSink({ filePath, flushBufferThreshold: 1 })
+    setActiveSink(sink)
+    const error = Object.assign(new Error('database or disk is full'), { code: 'SQLITE_FULL' })
+
+    traceAgentSessionError({ step: 'journal-rollback', error })
+    sink.flush()
+    sink.close()
+
+    const cause = failureCause(readTrace(filePath)[0])
+    expect(cause).toContain('database or disk is full')
+    expect(cause).toContain('[code] SQLITE_FULL')
+  })
+
+  it('keeps its own step and session over same-named detail keys', () => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const filePath = join(dir, 'main.trace.ndjson')
+    const sink = createLocalFileSink({ filePath, flushBufferThreshold: 1 })
+    setActiveSink(sink)
+
+    traceAgentSessionError({
+      step: 'idle-sweep',
+      sessionId: 'session-1',
+      error: 'x',
+      detail: { step: 'forged', sessionId: 'session-2', fence: 3 }
+    })
+    sink.flush()
+    sink.close()
+
+    expect(readTrace(filePath)[0].attributes).toEqual({
+      step: 'idle-sweep',
+      sessionId: 'session-1',
+      fence: 3
+    })
+    expect(warn).toHaveBeenCalledWith(
+      '[agent-session] idle-sweep failed',
+      { sessionId: 'session-1', fence: 3, step: 'forged' },
+      'x'
+    )
+  })
+
+  // Reclassifying a step edits this list, next to the reason in the step table.
+  const kindOnlySteps: readonly AgentSessionErrorStep[] = [
+    'operation-uncertainty-persist',
+    'refused-operation-settlement',
+    'recovery-capsule-read',
+    'recovery-capsule-record',
+    'recovery-witness-begin',
+    'recovery-witness-capture',
+    'recovery-records-forget',
+    'restart-offer-prune',
+    'restart-offer-withdraw',
+    'restart-offer-complete',
+    'restart-offer-rollback',
+    'restart-offer-refresh',
+    'restart-failure-record',
+    'restart-continuation-send',
+    'restart-continuation-note'
+  ]
+
+  it('keeps exactly the pinned steps to the error kind', () => {
+    const tableKindSteps = Object.entries(AGENT_SESSION_ERROR_STEPS)
+      .filter(([, recorded]) => recorded === 'kind')
+      .map(([step]) => step)
+    expect(tableKindSteps.sort()).toEqual([...kindOnlySteps].sort())
+  })
+
+  it.each(kindOnlySteps)('keeps %s to the error kind, in the trace and on the console', (step) => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const filePath = join(dir, 'main.trace.ndjson')
+    const sink = createLocalFileSink({ filePath, flushBufferThreshold: 1 })
+    setActiveSink(sink)
+    // What a corrupt capsule's parse throws: V8 quotes the input's first 10 characters.
+    const quoting = syntaxErrorQuoting('my private words')
+    expect(String(quoting)).toContain('my private')
+    const error = new Error('outer', { cause: quoting })
+
+    traceAgentSessionError({ step, sessionId: 'session-1', error })
+    sink.flush()
+    sink.close()
+
+    expect(readFileSync(filePath, 'utf8')).not.toContain('my private')
+    expect(readTrace(filePath)).toEqual([
+      expect.objectContaining({ exit: { _tag: 'Failure', cause: 'Error' } })
+    ])
+    expect(warn).toHaveBeenCalledExactlyOnceWith(
+      `[agent-session] ${step} failed`,
+      { sessionId: 'session-1' },
+      'Error'
+    )
+  })
+
+  it('keeps a recovery step to the error kind, in the trace and on the console', () => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const filePath = join(dir, 'main.trace.ndjson')
+    const sink = createLocalFileSink({ filePath, flushBufferThreshold: 1 })
+    setActiveSink(sink)
+    const error = Object.assign(new Error('latest prompt: "my private words"'), { code: 'EISDIR' })
+
+    traceAgentSessionError({ step: 'recovery-capsule-record', error })
+    sink.flush()
+    sink.close()
+
+    expect(readTrace(filePath)).toEqual([
+      expect.objectContaining({ exit: { _tag: 'Failure', cause: 'Error EISDIR' } })
+    ])
+    expect(warn).toHaveBeenCalledExactlyOnceWith(
+      '[agent-session] recovery-capsule-record failed',
+      {},
+      'Error EISDIR'
+    )
+  })
+
+  it('still writes the console line with no trace sink installed', () => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    const error = new Error('boom')
+
+    traceAgentSessionError({ step: 'idle-sweep', sessionId: 'session-1', error })
+
+    expect(warn).toHaveBeenCalledWith(
+      '[agent-session] idle-sweep failed',
+      { sessionId: 'session-1' },
+      error
+    )
+  })
+
+  it('never throws, whatever the sink or the console does', () => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {
+      throw new Error('console gone')
+    })
+    setActiveSink({
+      push: () => {
+        throw new Error('disk full')
+      },
+      flush: () => {},
+      close: () => {}
+    })
+
+    expect(() =>
+      traceAgentSessionError({ step: 'event-sink', sessionId: 'session-1', error: 'x' })
+    ).not.toThrow()
+    expect(warn).toHaveBeenCalledTimes(1)
+  })
+})
+
+function syntaxErrorQuoting(text: string): unknown {
+  try {
+    JSON.parse(text)
+  } catch (error) {
+    return error
+  }
+  throw new Error('expected a SyntaxError')
+}
diff --git a/src/main/observability/agent-session-error-trace.ts b/src/main/observability/agent-session-error-trace.ts
new file mode 100644
index 000000000000..1fd246b36b80
--- /dev/null
+++ b/src/main/observability/agent-session-error-trace.ts
@@ -0,0 +1,170 @@
+// Where a structured chat session's background errors go: failures a catch site swallows or
+// settles itself, so no caller ever sees them. Every such site reports here with its own step, so
+// none depends on a caller having wired a sink: the trace file is installed once at startup, and
+// the diagnostic bundle ships it. The console line is the only record where no trace sink is
+// installed (dev runs, orcad, diagnostics disabled); a packaged desktop main process owns no console.
+
+import { startSpan } from './tracer'
+
+/**
+ * Every step, and what its trace record and console line may carry: `full` records the error's
+ * stack and cause chain; `kind` records only its class and code. The trace redactor strips
+ * credentials, not prose or paths, so a step whose error can quote user content must be `kind`.
+ * The recovery capsule steps are, because a corrupt capsule fails `JSON.parse` in
+ * agent-session-recovery-capsule-entries.ts, and a SyntaxError message quotes the capsule's text.
+ * The operation-settlement and restart-continuation steps are because the restart privacy tests
+ * pin that their errors never reach a log.
+ */
+export const AGENT_SESSION_ERROR_STEPS = {
+  // Provider lifecycle delivered to the host.
+  'provider-started-settlement': 'full',
+  'provider-exit-settlement': 'full',
+  'provider-exit-barrier': 'full',
+  'provider-exit-lease-release': 'full',
+  'provider-start': 'full',
+  'started-options-persist': 'full',
+  'late-dispatch-settlement': 'full',
+  'unanswered-dispatch-release': 'full',
+  'dead-generation-settlement': 'full',
+  'sink-failure-recovery': 'full',
+  'operation-agent-start': 'full',
+  // Chat creation, before and after it commits.
+  'create-precommit': 'full',
+  'create-tab-publish': 'full',
+  // Claude's side of a session.
+  'claude-attachment-read': 'full',
+  'claude-dispatch-write': 'full',
+  'claude-history-window': 'full',
+  'claude-option-restore': 'full',
+  'claude-resume-point-persist': 'full',
+  'claude-exit-cursor-persist': 'full',
+  // The journal and what writes through it.
+  'event-sink': 'full',
+  'journal-delivery': 'full',
+  'journal-database-open': 'full',
+  'journal-open-read': 'full',
+  'journal-open-write': 'full',
+  'journal-open-pending-doubt': 'full',
+  'journal-rollback': 'full',
+  'journal-row-bookkeeping': 'full',
+  'legacy-journal-import': 'full',
+  'legacy-journal-retire': 'full',
+  'gone-generation-settlement': 'full',
+  'death-evidence-resettle': 'full',
+  'restart-reconciliation': 'full',
+  'dispatch-doubt-record': 'full',
+  // Leases.
+  'lease-probe': 'full',
+  'lease-renewal': 'full',
+  // Delivery, queued drafts and Stop.
+  'delivery-wake': 'full',
+  'delivery-loop': 'full',
+  'delivery-loop-failure-settlement': 'full',
+  'idle-sweep': 'full',
+  'queued-drain': 'full',
+  'queued-send-failure-hold': 'full',
+  'queued-owed-settlement': 'full',
+  'queued-repair': 'full',
+  'queued-abandon': 'full',
+  'queue-pause-retire': 'full',
+  'clear-draft-carry': 'full',
+  'stop-owed-settlement': 'full',
+  'stop-queue-pause': 'full',
+  'operation-uncertainty-persist': 'kind',
+  'refused-operation-settlement': 'kind',
+  'rewind-recovery': 'full',
+  // Status projection.
+  'status-publish': 'full',
+  'status-forget': 'full',
+  'status-observer': 'full',
+  'child-work-publish': 'full',
+  // Restart recovery.
+  'recovery-capsule-read': 'kind',
+  'recovery-capsule-record': 'kind',
+  'recovery-witness-begin': 'kind',
+  'recovery-witness-capture': 'kind',
+  'recovery-records-forget': 'kind',
+  'restart-offer-prune': 'kind',
+  'restart-offer-withdraw': 'kind',
+  'restart-offer-complete': 'kind',
+  'restart-offer-rollback': 'kind',
+  'restart-offer-refresh': 'kind',
+  'restart-failure-record': 'kind',
+  'restart-continuation-send': 'kind',
+  'restart-continuation-note': 'kind',
+  // Chat tabs.
+  'tab-visibility-restore': 'full',
+  'worker-tab-retire': 'full'
+} as const satisfies Record<string, 'full' | 'kind'>
+
+/** Closed so trace readers can rely on the vocabulary; add a step above with its catch site. */
+export type AgentSessionErrorStep = keyof typeof AGENT_SESSION_ERROR_STEPS
+
+export type AgentSessionErrorReport = {
+  step: AgentSessionErrorStep
+  sessionId?: string
+  error: unknown
+  /** Ids and closed-vocabulary facts only; attributes pass through the trace redactor. */
+  detail?: Record<string, string | number | boolean>
+}
+
+const SPAN_NAME = 'agent-session.failure'
+const MAX_CAUSE_DEPTH = 5
+const MAX_AGGREGATE_ERRORS = 10
+
+/** Never throws: reporting is bookkeeping and must not replace the failure it describes. */
+export function traceAgentSessionError(report: AgentSessionErrorReport): void {
+  const { step, sessionId, error, detail } = report
+  const kindOnly = AGENT_SESSION_ERROR_STEPS[step] === 'kind'
+  // The report's own step and session win over a same-named detail key.
+  const context = { ...detail, ...(sessionId === undefined ? {} : { sessionId }) }
+  try {
+    startSpan(SPAN_NAME, { attributes: { ...context, step } }).fail(
+      kindOnly ? errorKind(error) : describeFailure(error)
+    )
+  } catch {
+    // The console line below still carries it.
+  }
+  try {
+    console.warn(`[agent-session] ${step} failed`, context, kindOnly ? errorKind(error) : error)
+  } catch {
+    // Nothing left to tell.
+  }
+}
+
+/** The whole chain: a wrapper's message alone names the step and nothing else. */
+function describeFailure(error: unknown, depth = 0): string {
+  if (!(error instanceof Error)) {
+    return String(error)
+  }
+  const code = errorCode(error)
+  // `code` (SQLITE_*, journal_*) is often the only part the message leaves out.
+  const head = `${error.stack ?? `${error.name}: ${error.message}`}${code === undefined ? '' : `\n[code] ${code}`}`
+  if (depth >= MAX_CAUSE_DEPTH) {
+    return head
+  }
+  const parts = [head]
+  if (error instanceof AggregateError) {
+    for (const inner of error.errors.slice(0, MAX_AGGREGATE_ERRORS)) {
+      parts.push(`[aggregated] ${describeFailure(inner, depth + 1)}`)
+    }
+  }
+  if (error.cause !== undefined) {
+    parts.push(`[cause] ${describeFailure(error.cause, depth + 1)}`)
+  }
+  return parts.join('\n')
+}
+
+/** What failed, without anything it said: its class and, for system errors, its code. */
+function errorKind(error: unknown): string {
+  if (!(error instanceof Error)) {
+    return typeof error
+  }
+  const code = errorCode(error)
+  return code === undefined ? error.name : `${error.name} ${code}`
+}
+
+function errorCode(error: Error): string | number | undefined {
+  const code = 'code' in error ? error.code : undefined
+  return typeof code === 'string' || typeof code === 'number' ? code : undefined
+}
diff --git a/src/main/runtime/rpc/methods/structured-agent-session-at-rest.test.ts b/src/main/runtime/rpc/methods/structured-agent-session-at-rest.test.ts
index 9cbad804cd50..db2e820c5f37 100644
--- a/src/main/runtime/rpc/methods/structured-agent-session-at-rest.test.ts
+++ b/src/main/runtime/rpc/methods/structured-agent-session-at-rest.test.ts
@@ -287,8 +287,8 @@ describe('the accessor', () => {
     const warn = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
     const logged = (): unknown[] =>
       warn.mock.calls
-        .filter(([line]) => line === '[agent-session] opening the conversation for a read failed:')
-        .map(([, error]) => error)
+        .filter(([line]) => line === '[agent-session] journal-open-read failed')
+        .map(([, , error]) => error)
     const reconnect = async (): Promise<RpcResponse[]> => [
       ...(await call('agentSession.subscribe', { sessionId: SESSION })),
       ...(await call('agentSession.history', { sessionId: SESSION, direction: 'tail' }))
diff --git a/src/main/runtime/rpc/methods/structured-agent-session-create.ts b/src/main/runtime/rpc/methods/structured-agent-session-create.ts
index 0c3b7b087133..b45053ba2672 100644
--- a/src/main/runtime/rpc/methods/structured-agent-session-create.ts
+++ b/src/main/runtime/rpc/methods/structured-agent-session-create.ts
@@ -27,6 +27,7 @@ import type { StructuredAgentSessionHost } from '../../../native-chat/agent-sess
 import type { StructuredAgentSessionCaller } from '../../../native-chat/agent-session-wire/structured-agent-session-host-types'
 import type { StructuredAgentSessionResumeSource } from '../../../../shared/structured-agent-session-create'
 import type { OrcaRuntimeService } from '../../orca-runtime'
+import { traceAgentSessionError } from '../../../observability/agent-session-error-trace'
 import {
   resolveUncommittedStructuredCreate,
   type StructuredCreateRefused
@@ -142,7 +143,7 @@ export async function commitStructuredAgentSessionCreate(args: {
       ...(surfaceTabId ? { tabId: surfaceTabId } : {})
     })
   } catch (error) {
-    console.warn('[agent-session] create committed before tab publication failed', error)
+    traceAgentSessionError({ step: 'create-tab-publish', sessionId: result.value.sessionId, error })
     return {
       ok: false,
       refusal: refuse(
diff --git a/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts b/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts
index 4038fe9e40d2..85c542c3206c 100644
--- a/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts
+++ b/src/main/runtime/rpc/methods/structured-agent-session-precommit-refusal.ts
@@ -18,6 +18,7 @@ import {
   type AgentSessionWireRefusal,
   type AgentSessionWireRefusalCode
 } from '../../../../shared/agent-session-wire'
+import { traceAgentSessionError } from '../../../observability/agent-session-error-trace'
 
 export type StructuredCreateRefused = { refusal: AgentSessionWireRefusal }
 
@@ -56,8 +57,8 @@ function precommitRefusal(error: unknown): AgentSessionWireRefusal {
   }
   const message = error instanceof Error ? error.message : String(error)
   // A code-less failure here is often a defect, not a policy answer; the refusal keeps the user
-  // moving, the log keeps the cause findable. Nothing names its situation, so it carries no reason.
-  console.warn('[agent-session] create refused before it committed anything', error)
+  // moving, the trace keeps the cause findable. Nothing names its situation, so it carries no reason.
+  traceAgentSessionError({ step: 'create-precommit', error })
   return refuseUnclassified(
     UNCODED_PRECOMMIT_REFUSAL_CODE,
     `Orca could not prepare a structured agent chat for this workspace: ${message}`
diff --git a/src/main/runtime/structured-agent-session-close.ts b/src/main/runtime/structured-agent-session-close.ts
index 668b7f218903..ad626236a482 100644
--- a/src/main/runtime/structured-agent-session-close.ts
+++ b/src/main/runtime/structured-agent-session-close.ts
@@ -19,6 +19,7 @@ import {
   observeStructuredWorker,
   structuredSessionCloseSettled
 } from './structured-worker-authority'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 
 export type StructuredAgentSessionCloseOutcome = {
   stopped: boolean
@@ -146,9 +147,6 @@ async function restorePersistedTabVisibility(
   try {
     await host.setSessionTabVisibility?.(sessionId, true, tabId)
   } catch (error) {
-    console.warn(
-      `[structured-session-close] could not restore the chat tab for ${sessionId} after a failed close`,
-      error
-    )
+    traceAgentSessionError({ step: 'tab-visibility-restore', sessionId, error })
   }
 }
diff --git a/src/main/runtime/structured-agent-session-host-refusal.test.ts b/src/main/runtime/structured-agent-session-host-refusal.test.ts
index 689ac3df969c..1fff0669e029 100644
--- a/src/main/runtime/structured-agent-session-host-refusal.test.ts
+++ b/src/main/runtime/structured-agent-session-host-refusal.test.ts
@@ -25,6 +25,11 @@ import {
   ensureStructuredAgentSessionHost,
   stopStructuredAgentSessionRuntime
 } from './structured-agent-session-runtime'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
+
+vi.mock('../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 let root: string
 
@@ -107,7 +112,8 @@ describe('a process whose journal will not open', () => {
     earlier.pragma('user_version = 2')
     earlier.close()
     const before = await digest(path)
-    const warn = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
+    const reports = vi.mocked(traceAgentSessionError)
+    reports.mockClear()
 
     for (let attempt = 0; attempt < 3; attempt += 1) {
       await expect(install()).rejects.toMatchObject({
@@ -118,8 +124,8 @@ describe('a process whose journal will not open', () => {
       reason: 'journalCorrupt',
       message: 'Unable to load this chat.'
     })
-    expect(warn).toHaveBeenCalledOnce()
-    const logged = String(warn.mock.calls[0]?.[1])
+    expect(reports).toHaveBeenCalledOnce()
+    const logged = String(reports.mock.calls[0]?.[0].error)
     expect(logged).toContain(path)
     expect(logged).toContain('unreleased development build')
     expect(logged).toContain('move the file aside')
@@ -143,8 +149,6 @@ describe('a process whose journal will not open', () => {
 })
 
 describe('logging a journal that will not open', () => {
-  const OPEN_FAILED = '[structured-agent-session] opening the chat journal database failed'
-
   async function writeJunkJournal(): Promise<void> {
     const path = journalDatabasePath(root)
     await rm(`${path}-wal`, { force: true })
@@ -154,8 +158,11 @@ describe('logging a journal that will not open', () => {
 
   // Every chat request retries the open; the same failure each time is one log, not one per request.
   it('logs a repeated failure once, with its stack, and again after an open succeeds', async () => {
-    const warn = vi.spyOn(console, 'warn').mockImplementation(() => undefined)
-    const openFailureLogs = () => warn.mock.calls.filter(([message]) => message === OPEN_FAILED)
+    vi.mocked(traceAgentSessionError).mockClear()
+    const openFailureLogs = () =>
+      vi
+        .mocked(traceAgentSessionError)
+        .mock.calls.filter(([report]) => report.step === 'journal-database-open')
     await install()
     await stopStructuredAgentSessionRuntime()
     await writeJunkJournal()
@@ -166,8 +173,8 @@ describe('logging a journal that will not open', () => {
       })
     }
     expect(openFailureLogs()).toHaveLength(1)
-    expect(openFailureLogs()[0]?.[1]).toBeInstanceOf(Error)
-    expect(openFailureLogs()[0]?.[1]).toHaveProperty('stack', expect.stringContaining('\n'))
+    expect(openFailureLogs()[0]?.[0].error).toBeInstanceOf(Error)
+    expect(openFailureLogs()[0]?.[0].error).toHaveProperty('stack', expect.stringContaining('\n'))
 
     await unlink(journalDatabasePath(root))
     await install()
diff --git a/src/main/runtime/structured-agent-session-journal-open.ts b/src/main/runtime/structured-agent-session-journal-open.ts
index 6972a18a7960..3dbedb46f30b 100644
--- a/src/main/runtime/structured-agent-session-journal-open.ts
+++ b/src/main/runtime/structured-agent-session-journal-open.ts
@@ -3,6 +3,7 @@
 import { JournalHostDatabase } from '../native-chat/agent-session-journal/journal-host-database'
 import { journalOpenRefusalError } from '../native-chat/agent-session-journal/journal-open-failure'
 import { recordStructuredAgentSessionHostInstallRefusal } from './structured-agent-session-host-refusal'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 
 // Every chat request retries a failed open, so each distinct failure is logged once, with its stack.
 let lastLoggedOpenFailure: string | null = null
@@ -16,7 +17,7 @@ function logOpenFailureOnce(error: unknown): void {
     return
   }
   lastLoggedOpenFailure = failure
-  console.warn('[structured-agent-session] opening the chat journal database failed', error)
+  traceAgentSessionError({ step: 'journal-database-open', error })
 }
 
 /** The journal database. A refusal is recorded for the gate and thrown to the caller; the next
diff --git a/src/main/runtime/structured-agent-session-lifecycle-delivery.test.ts b/src/main/runtime/structured-agent-session-lifecycle-delivery.test.ts
new file mode 100644
index 000000000000..ac0e822d7ed9
--- /dev/null
+++ b/src/main/runtime/structured-agent-session-lifecycle-delivery.test.ts
@@ -0,0 +1,67 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
+import { createStructuredAgentSessionLifecycleDelivery } from './structured-agent-session-lifecycle-delivery'
+
+vi.mock('../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
+
+const EXIT = {
+  type: 'ended',
+  sessionId: 'session-1',
+  reason: 'provider crashed',
+  cause: 'unexpected-exit',
+  fence: 1,
+  acquisitionGeneration: 'generation-1'
+} as const
+
+afterEach(() => {
+  vi.mocked(traceAgentSessionError).mockClear()
+})
+
+describe('structured agent-session lifecycle delivery', () => {
+  // No installer supplies a sink any more, so a failed exit recovery must still reach the trace.
+  it('reports a failed recovery with its session and keeps the chain moving', async () => {
+    const failure = new Error('journal write failed')
+    const handle = vi.fn().mockRejectedValueOnce(failure).mockResolvedValue(undefined)
+    const delivery = createStructuredAgentSessionLifecycleDelivery({
+      handle,
+      drainObservedExits: async () => undefined
+    })
+
+    delivery.deliver(EXIT)
+    delivery.deliver({ ...EXIT, sessionId: 'session-2' })
+    await delivery.drain()
+
+    expect(handle).toHaveBeenCalledTimes(2)
+    expect(traceAgentSessionError).toHaveBeenCalledExactlyOnceWith({
+      step: 'provider-exit-settlement',
+      sessionId: 'session-1',
+      error: failure
+    })
+  })
+
+  it('reports a failed start settlement under its own step', async () => {
+    const failure = new Error('options write failed')
+    const delivery = createStructuredAgentSessionLifecycleDelivery({
+      handle: vi.fn().mockRejectedValue(failure),
+      drainObservedExits: async () => undefined
+    })
+
+    delivery.deliver({
+      type: 'started',
+      sessionId: 'session-1',
+      fence: 1,
+      acquisitionGeneration: 'generation-1',
+      reportedOptions: { model: 'model-1' },
+      restoreSkippedOptions: []
+    })
+    await delivery.drain()
+
+    expect(traceAgentSessionError).toHaveBeenCalledExactlyOnceWith({
+      step: 'provider-started-settlement',
+      sessionId: 'session-1',
+      error: failure
+    })
+  })
+})
diff --git a/src/main/runtime/structured-agent-session-lifecycle-delivery.ts b/src/main/runtime/structured-agent-session-lifecycle-delivery.ts
index 961c4d50aa84..3ed90fccad25 100644
--- a/src/main/runtime/structured-agent-session-lifecycle-delivery.ts
+++ b/src/main/runtime/structured-agent-session-lifecycle-delivery.ts
@@ -7,10 +7,10 @@
 // serialized step, and is tracked here so the same drain still waits for it.
 
 import type { StructuredAgentSessionLifecycleEvent } from '../native-chat/agent-session-wire/structured-agent-session-adapter'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 
 export function createStructuredAgentSessionLifecycleDelivery(input: {
   handle: (event: StructuredAgentSessionLifecycleEvent) => Promise<void> | undefined
-  onError?: (input: { scope: string; error: unknown }) => void
   /** Exits the adapter has observed but not yet published. */
   drainObservedExits: () => Promise<void>
 }): {
@@ -24,8 +24,11 @@ export function createStructuredAgentSessionLifecycleDelivery(input: {
     try {
       await input.handle(event)
     } catch (error) {
-      const scope = event.type === 'started' ? 'started' : 'exit'
-      input.onError?.({ scope: `structured-agent-session-${scope}:${event.sessionId}`, error })
+      traceAgentSessionError({
+        step: event.type === 'started' ? 'provider-started-settlement' : 'provider-exit-settlement',
+        sessionId: event.sessionId,
+        error
+      })
     }
   }
   return {
diff --git a/src/main/runtime/structured-agent-session-runtime.ts b/src/main/runtime/structured-agent-session-runtime.ts
index 82c9803e2a76..4285b8bc03ab 100644
--- a/src/main/runtime/structured-agent-session-runtime.ts
+++ b/src/main/runtime/structured-agent-session-runtime.ts
@@ -55,6 +55,7 @@ import { createStructuredAgentEnvironmentResolvers } from './structured-agent-sh
 import type { ClaudeStructuredAuthPolicy } from '../claude-accounts/claude-structured-auth-policy'
 import { createStructuredClaudeRuntimeAdapter } from './structured-claude-runtime-adapter'
 import { createStructuredAgentSessionLifecycleDelivery } from './structured-agent-session-lifecycle-delivery'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 import { agentModelCatalogStore } from '../native-chat/agent-model-catalog/agent-model-catalog-store'
 import {
   modelCatalogHostDeps,
@@ -101,7 +102,6 @@ export type StructuredAgentSessionRuntimeDeps = {
   /** Which login-shell variables Codex and Claude children inherit; absent inherits all. */
   resolveShellEnvironmentPolicy?: () => NativeChatShellEnvironmentPolicy
   resolveCodexOverrides?: () => NodeJS.ProcessEnv
-  onError?: (input: { scope: string; error: unknown }) => void
   /** Every structured-session status projection, for host-side reactions such as the first-work
    *  workspace rename that CLI agents get from their hooks. */
   onSessionStatusChanged?: StructuredAgentSessionHostDeps['onSessionStatusChanged']
@@ -217,7 +217,6 @@ async function installOnJournal(
   let host: StructuredAgentSessionHost | null = null
   const lifecycle = createStructuredAgentSessionLifecycleDelivery({
     handle: (event) => host?.handleAdapterEvent(event),
-    ...(deps.onError ? { onError: deps.onError } : {}),
     // Claude publishes an observed exit only after its close ladder and transcript write; Codex
     // publishes inside its own exit callback and needs nothing.
     drainObservedExits: () => claude.drainObservedExits()
@@ -225,9 +224,10 @@ async function installOnJournal(
   const onDispatchSettledLate = (
     settlement: Parameters<StructuredAgentSessionHost['settleLateDispatch']>[0]
   ): void => {
-    void host?.settleLateDispatch(settlement).catch((error) =>
-      deps.onError?.({
-        scope: `structured-agent-session-late-settlement:${settlement.sessionId}`,
+    void host?.settleLateDispatch(settlement).catch((error: unknown) =>
+      traceAgentSessionError({
+        step: 'late-dispatch-settlement',
+        sessionId: settlement.sessionId,
         error
       })
     )
@@ -239,11 +239,8 @@ async function installOnJournal(
         sessionId,
         reason: DISPATCH_DOUBT_PROVIDER_IDLE
       })
-      .catch((error) =>
-        deps.onError?.({
-          scope: `structured-agent-session-unanswered-dispatch:${sessionId}`,
-          error
-        })
+      .catch((error: unknown) =>
+        traceAgentSessionError({ step: 'unanswered-dispatch-release', sessionId, error })
       )
   }
   const codex = new CodexStructuredSessionAdapter({
@@ -315,8 +312,6 @@ async function installOnJournal(
             await deps.resolveLaunchArgs!(provider)
         }
       : {}),
-    onEventSinkError: ({ sessionId, error }) =>
-      deps.onError?.({ scope: `structured-agent-session-journal:${sessionId}`, error }),
     ...(deps.onSessionStatusChanged ? { onSessionStatusChanged: deps.onSessionStatusChanged } : {}),
     ...(deps.statusSink ? { statusSink: deps.statusSink } : {}),
     ...(deps.hasOpenDispatch ? { hasOpenDispatch: deps.hasOpenDispatch } : {}),
diff --git a/src/main/runtime/structured-agent-session-tab-retirement.ts b/src/main/runtime/structured-agent-session-tab-retirement.ts
index aee5ef6d719d..2f6c71621e16 100644
--- a/src/main/runtime/structured-agent-session-tab-retirement.ts
+++ b/src/main/runtime/structured-agent-session-tab-retirement.ts
@@ -11,6 +11,7 @@ import type {
   RuntimeMobileSessionTabsSnapshot
 } from '../../shared/runtime-types'
 import { structuredAgentSessionTabId } from '../../shared/structured-agent-session-projection'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
 
 /** The snapshot's tab for a structured session, matched by session id and by published tab id. */
 export function findStructuredAgentSessionTab(
@@ -74,6 +75,6 @@ export function retireSettledStructuredWorkerTab(
   try {
     runtime?.retireStructuredAgentSessionTabFromSnapshot?.(sessionId)
   } catch (error) {
-    console.warn('[orchestration] structured worker tab retirement failed', sessionId, error)
+    traceAgentSessionError({ step: 'worker-tab-retire', sessionId, error })
   }
 }
diff --git a/src/main/runtime/structured-claude-pending-rewind.test.ts b/src/main/runtime/structured-claude-pending-rewind.test.ts
index 137b7ff6961f..ca1df51ec9fe 100644
--- a/src/main/runtime/structured-claude-pending-rewind.test.ts
+++ b/src/main/runtime/structured-claude-pending-rewind.test.ts
@@ -24,6 +24,11 @@ import type { AgentSessionRecordStore } from './agent-session-record-store'
 import { openTestAgentSessionRecordStore } from './agent-session-record-store-test-harness'
 import { createStructuredClaudeRuntimeAdapter } from './structured-claude-runtime-adapter'
 import { openTestJournalHostDatabase } from '../native-chat/agent-session-journal/journal-host-database-test-support'
+import { traceAgentSessionError } from '../observability/agent-session-error-trace'
+
+vi.mock('../observability/agent-session-error-trace', () => ({
+  traceAgentSessionError: vi.fn()
+}))
 
 const caller = { callerKey: 'desktop' }
 const PROVIDER_SESSION_ID = claudeSessionIdForOrcaSession(HOST_TEST_SESSION)
@@ -173,7 +178,7 @@ describe('Claude rewind is unsupported', () => {
   )
 
   it('still attaches when settling the pending rewind fails, and logs it', async () => {
-    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    vi.mocked(traceAgentSessionError).mockClear()
     await seedPendingRewind('prepared')
     const transition = store.transitionHandoff.bind(store)
     vi.spyOn(store, 'transitionHandoff').mockImplementation((sessionId, apply) =>
@@ -189,9 +194,12 @@ describe('Claude rewind is unsupported', () => {
     await reattach()
 
     expect(store.getRecord(HOST_TEST_SESSION)?.rewind?.phase).toBe('prepared')
-    expect(warn).toHaveBeenCalledWith(
-      '[structured-rewind] pending Claude rewind was not settled:',
-      expect.objectContaining({ sessionId: HOST_TEST_SESSION, error: expect.any(Error) })
+    expect(traceAgentSessionError).toHaveBeenCalledWith(
+      expect.objectContaining({
+        step: 'rewind-recovery',
+        sessionId: HOST_TEST_SESSION,
+        error: expect.any(Error)
+      })
     )
   })
 })
diff --git a/tests/e2e/codex-child-approval-activity-row.unit.test.ts b/tests/e2e/codex-child-approval-activity-row.unit.test.ts
index dbb2a5d8e9cb..985982ab91e8 100644
--- a/tests/e2e/codex-child-approval-activity-row.unit.test.ts
+++ b/tests/e2e/codex-child-approval-activity-row.unit.test.ts
@@ -152,7 +152,7 @@ async function openHost() {
   })
   const events: AgentSessionStatusEvent[] = []
   feed.subscribe({ id: 'renderer', emit: (event) => events.push(event) })
-  const deferred = createDeferredStructuredAgentSessionEventSink()
+  const deferred = createDeferredStructuredAgentSessionEventSink({ onFailure: () => {} })
   const publish = (): void => feed.publish(SESSION, journal)
   deferred.bind({ journal, fence: 1, publish })
   const prompts: string[] = []