diff --git a/packages/sdk/src/adapters/codex.ts b/packages/sdk/src/adapters/codex.ts
index 3b1beb3f8..f709174e6 100644
--- a/packages/sdk/src/adapters/codex.ts
+++ b/packages/sdk/src/adapters/codex.ts
@@ -38,7 +38,12 @@ export const codexAdapter: HeadlessAdapter = {
   buildAgentInvocation(instruction: string, model?: string): CliInvocation {
     return {
       args: [
-        'exec', '--ephemeral', '--skip-git-repo-check',
+        // Real steps must retain Codex's native session under CODEX_HOME (or
+        // ~/.codex). Hosted Relayflow teardown captures that provider history
+        // and uploads it to Relayhistory; --ephemeral silently leaves nothing
+        // for the bounded flush to capture. Readiness probes above stay
+        // ephemeral because they are diagnostics, not workflow steps.
+        'exec', '--skip-git-repo-check',
         // Agent-mode is where the flow explicitly delegates code changes to
         // the CLI. Without this flag codex prompts for approval on every
         // write, gets nothing (no TTY), and completes "successfully" without
@@ -54,7 +59,7 @@ export const codexAdapter: HeadlessAdapter = {
 
   buildLlmInvocation(prompt: string, model?: string): CliInvocation {
     return {
-      args: ['exec', '--ephemeral', '--sandbox', 'read-only', '--skip-git-repo-check',
+      args: ['exec', '--sandbox', 'read-only', '--skip-git-repo-check',
         ...(model === undefined ? [] : ['--model', model]), prompt],
       timeoutMs: 0,
     };
diff --git a/packages/sdk/tests/adapters/codex.test.ts b/packages/sdk/tests/adapters/codex.test.ts
index 7299a92a9..4bce9e074 100644
--- a/packages/sdk/tests/adapters/codex.test.ts
+++ b/packages/sdk/tests/adapters/codex.test.ts
@@ -27,10 +27,10 @@ describe('codexAdapter — HeadlessAdapter contract', () => {
     expect(inv.args).toContain('gpt-6-astra');
   });
 
-  it('buildAgentInvocation uses exec --ephemeral --skip-git-repo-check with instruction at the tail', () => {
+  it('buildAgentInvocation persists provider history and keeps the instruction at the tail', () => {
     const inv = codexAdapter.buildAgentInvocation('build the thing', 'gpt-6-astra');
     expect(inv.args[0]).toBe('exec');
-    expect(inv.args).toContain('--ephemeral');
+    expect(inv.args).not.toContain('--ephemeral');
     expect(inv.args).toContain('--skip-git-repo-check');
     expect(inv.args).toContain('--model');
     expect(inv.args).toContain('gpt-6-astra');
@@ -44,8 +44,9 @@ describe('codexAdapter — HeadlessAdapter contract', () => {
     expect(inv.args).not.toContain('--sandbox');
   });
 
-  it('buildLlmInvocation adds --sandbox read-only', () => {
+  it('buildLlmInvocation persists provider history in its read-only sandbox', () => {
     const inv = codexAdapter.buildLlmInvocation('summarize');
+    expect(inv.args).not.toContain('--ephemeral');
     expect(inv.args).toContain('--sandbox');
     expect(inv.args).toContain('read-only');
   });
diff --git a/packages/sdk/tests/cli-adapter.test.ts b/packages/sdk/tests/cli-adapter.test.ts
index 0fd07ac73..ef4348463 100644
--- a/packages/sdk/tests/cli-adapter.test.ts
+++ b/packages/sdk/tests/cli-adapter.test.ts
@@ -55,7 +55,7 @@ describe('typed CLI adapters', () => {
       timeoutMs: 60_000,
     });
     expect(agentExecution(kind, 'Review.', 'gpt-model')).toEqual({
-      args: ['exec', '--ephemeral', '--skip-git-repo-check', '--dangerously-bypass-approvals-and-sandbox',
+      args: ['exec', '--skip-git-repo-check', '--dangerously-bypass-approvals-and-sandbox',
         '--model', 'gpt-model', 'Review.'],
       timeoutMs: 0,
     });
diff --git a/packages/sdk/tests/live-kernel.test.ts b/packages/sdk/tests/live-kernel.test.ts
index 6f5865e45..a51786f17 100644
--- a/packages/sdk/tests/live-kernel.test.ts
+++ b/packages/sdk/tests/live-kernel.test.ts
@@ -1106,7 +1106,7 @@ process.stdout.write('{"must_not":"execute"}');
 
   it.each([
     ['claude', '-p --dangerously-skip-permissions --model declared-model-xyz'],
-    ['codex', 'exec --ephemeral --skip-git-repo-check --dangerously-bypass-approvals-and-sandbox --model declared-model-xyz'],
+    ['codex', 'exec --skip-git-repo-check --dangerously-bypass-approvals-and-sandbox --model declared-model-xyz'],
   ] as const)('AgentWorker executes the raw %s adapter with its real model flag', async (name, prefix) => {
     const dataDir = temporaryDirectory(`flows-live-${name}-adapter-`);
     await startDaemon(dataDir);