Fix spawned broker and CLI env separation

src/main/broker-binary.ts

@@ -19,10 +19,13 @@ import { app } from 'electron'
 import { canExecute } from './mcp-command'
 
 function resolveBrokerBinaryOverride(): string | null {
-  const configured = process.env.AGENT_RELAY_BIN?.trim()
+  const brokerOverride = process.env.BROKER_BINARY_PATH?.trim()
+  const legacyOverride = process.env.AGENT_RELAY_BIN?.trim()
+  const configured = brokerOverride || legacyOverride
   if (!configured) return null
   if (canExecute(configured)) return configured
-  console.warn('[broker] Ignoring AGENT_RELAY_BIN because it is not executable:', configured)
+  const variable = brokerOverride ? 'BROKER_BINARY_PATH' : 'AGENT_RELAY_BIN'
+  console.warn(`[broker] Ignoring ${variable} because it is not executable:`, configured)
   return null
 }
 
@@ -107,6 +110,29 @@ function inspectBrokerInitCliFlags(binaryPath: string): Promise<BrokerInitCliFla
   })
 }
 
+function inspectAgentRelayCloudCLI(binaryPath: string): Promise<boolean> {
+  return new Promise((resolve) => {
+    execFile(binaryPath, ['cloud', 'session', '--help'], {
+      encoding: 'utf8',
+      timeout: 2_000,
+      windowsHide: true,
+      // npm exposes global CLIs as .cmd wrappers on Windows.
+      shell: process.platform === 'win32'
+    }, (_err, stdout, stderr) => {
+      // Help may be written to stderr and some wrappers exit non-zero after
+      // printing it. The command signature, not the exit code, is the
+      // capability contract we need to establish.
+      resolve(/agent-relay cloud session/i.test(`${stdout || ''}${stderr || ''}`))
+    })
+  })
+}
+
+async function resolveWorkerAgentRelayCLIOverride(brokerBinaryPath: string): Promise<string | undefined> {
+  const configured = process.env.AGENT_RELAY_BIN?.trim()
+  if (!configured || configured === brokerBinaryPath || !canExecute(configured)) return undefined
+  return await inspectAgentRelayCloudCLI(configured) ? configured : undefined
+}
+
 function brokerBinaryCompatShimSource(): string {
   return `#!/usr/bin/env node
 const { spawn } = require('node:child_process')
@@ -203,9 +229,15 @@ async function ensureBrokerBinaryCompatShim(): Promise<string> {
 // `binaryPath` is what Pear launches (possibly the legacy compat shim);
 // `realBinaryPath` is always the actual broker binary, for callers that hand
 // the binary itself to other processes.
-export async function resolveHarnessBrokerBinary(workspaceKey?: string): Promise<{ binaryPath: string; realBinaryPath: string; env: NodeJS.ProcessEnv }> {
+export async function resolveHarnessBrokerBinary(workspaceKey?: string): Promise<{
+  binaryPath: string
+  realBinaryPath: string
+  agentRelayCLIPath: string | undefined
+  env: NodeJS.ProcessEnv
+}> {
   const binaryPath = resolveBundledBrokerBinary()
   const flags = await inspectBrokerInitCliFlags(binaryPath)
+  const agentRelayCLIPath = await resolveWorkerAgentRelayCLIOverride(binaryPath)
 
   if (workspaceKey && !flags.supportsWorkspaceKey) {
     throw new Error(
@@ -214,7 +246,7 @@ export async function resolveHarnessBrokerBinary(workspaceKey?: string): Promise
   }
 
   if (flags.supportsInstanceName) {
-    return { binaryPath, realBinaryPath: binaryPath, env: {} }
+    return { binaryPath, realBinaryPath: binaryPath, agentRelayCLIPath, env: {} }
   }
 
   if (!flags.supportsName) {
@@ -226,6 +258,7 @@ export async function resolveHarnessBrokerBinary(workspaceKey?: string): Promise
   return {
     binaryPath: shimPath,
     realBinaryPath: binaryPath,
+    agentRelayCLIPath,
     env: {
       PEAR_AGENT_RELAY_BROKER_BINARY: binaryPath,
       PEAR_AGENT_RELAY_BROKER_SUPPORTS_INSTANCE_NAME: flags.supportsInstanceName ? '1' : '0',

src/main/broker.test.ts

@@ -243,6 +243,7 @@ import {
 const PROJECT_ID = 'project-1'
 const originalMcpCommand = process.env.AGENT_RELAY_MCP_COMMAND
 const originalAgentRelayBin = process.env.AGENT_RELAY_BIN
+const originalBrokerBinaryPath = process.env.BROKER_BINARY_PATH
 const originalResourcesPathDescriptor = Object.getOwnPropertyDescriptor(process, 'resourcesPath')
 const originalPlatformDescriptor = Object.getOwnPropertyDescriptor(process, 'platform')
 const originalPublicEnv = process.env.PUBLIC
@@ -508,6 +509,7 @@ describe('resolveBundledBrokerBinary', () => {
 
   beforeEach(() => {
     electronMock.app.isPackaged = false
+    delete process.env.BROKER_BINARY_PATH
     if (originalAgentRelayBin === undefined) {
       delete process.env.AGENT_RELAY_BIN
     } else {
@@ -517,6 +519,11 @@ describe('resolveBundledBrokerBinary', () => {
 
   afterEach(async () => {
     electronMock.app.isPackaged = false
+    if (originalBrokerBinaryPath === undefined) {
+      delete process.env.BROKER_BINARY_PATH
+    } else {
+      process.env.BROKER_BINARY_PATH = originalBrokerBinaryPath
+    }
     if (originalAgentRelayBin === undefined) {
       delete process.env.AGENT_RELAY_BIN
     } else {
@@ -560,6 +567,7 @@ describe('resolveBundledBrokerBinary', () => {
   })
 
   it('checks the packaged optional broker binary in app.asar.unpacked', async () => {
+    delete process.env.AGENT_RELAY_BIN
     tempDir = await mkdtemp(join(tmpdir(), 'pear-broker-asar-'))
     const baseDir = join(tempDir, 'Resources', 'app.asar', 'out', 'main')
     const brokerPath = join(
@@ -601,6 +609,7 @@ describe('BrokerManager local + cloud coexistence', () => {
       Object.defineProperty(process, 'platform', originalPlatformDescriptor)
     }
     delete process.env.AGENT_RELAY_WORKSPACE_KEY
+    delete process.env.BROKER_BINARY_PATH
     if (originalAgentRelayBin === undefined) {
       delete process.env.AGENT_RELAY_BIN
     } else {
@@ -634,6 +643,16 @@ describe('BrokerManager local + cloud coexistence', () => {
     } else {
       process.env.AGENT_RELAY_WORKSPACE_KEY = inheritedWorkspaceKey
     }
+    if (originalAgentRelayBin === undefined) {
+      delete process.env.AGENT_RELAY_BIN
+    } else {
+      process.env.AGENT_RELAY_BIN = originalAgentRelayBin
+    }
+    if (originalBrokerBinaryPath === undefined) {
+      delete process.env.BROKER_BINARY_PATH
+    } else {
+      process.env.BROKER_BINARY_PATH = originalBrokerBinaryPath
+    }
     electronMock.app.isPackaged = false
     if (originalPlatformDescriptor) {
       Object.defineProperty(process, 'platform', originalPlatformDescriptor)
@@ -819,6 +838,72 @@ describe('BrokerManager local + cloud coexistence', () => {
     }
   })
 
+  it('does not expose the native broker as the spawned worker Agent Relay CLI', async () => {
+    const tempDir = await mkdtemp(join(tmpdir(), 'pear-worker-broker-env-'))
+    const brokerPath = join(tempDir, 'agent-relay-broker')
+    await writeFile(brokerPath, `#!/bin/sh
+if [ "$*" = "init --help" ]; then
+  echo "--instance-name --workspace-key"
+fi
+exit 0
+`)
+    await chmod(brokerPath, 0o755)
+    process.env.AGENT_RELAY_BIN = brokerPath
+    delete process.env.BROKER_BINARY_PATH
+    const manager = new BrokerManager()
+
+    try {
+      await manager.start(PROJECT_ID, '/tmp/project-1', 'pear-project-1', undefined as never, [])
+
+      const spawnOptions = mock.HarnessDriverClient.spawn.mock.calls[0]?.[0] as {
+        env?: NodeJS.ProcessEnv
+      } | undefined
+      expect(spawnOptions?.env?.BROKER_BINARY_PATH).toBe(brokerPath)
+      expect(spawnOptions?.env).not.toHaveProperty('AGENT_RELAY_BIN')
+      expect(spawnOptions?.env?.AGENT_RELAY_BIN).toBeUndefined()
+    } finally {
+      await manager.shutdown()
+      await rm(tempDir, { recursive: true, force: true })
+    }
+  })
+
+  it('preserves an intentional Agent Relay CLI override separately from the broker', async () => {
+    const tempDir = await mkdtemp(join(tmpdir(), 'pear-worker-cli-env-'))
+    const brokerPath = join(tempDir, 'agent-relay-broker')
+    const cliPath = join(tempDir, 'agent-relay')
+    await writeFile(brokerPath, `#!/bin/sh
+if [ "$*" = "init --help" ]; then
+  echo "--instance-name --workspace-key"
+fi
+exit 0
+`)
+    await writeFile(cliPath, `#!/bin/sh
+if [ "$*" = "cloud session --help" ]; then
+  echo "Usage: agent-relay cloud session [options]" >&2
+  exit 2
+fi
+exit 2
+`)
+    await chmod(brokerPath, 0o755)
+    await chmod(cliPath, 0o755)
+    process.env.BROKER_BINARY_PATH = brokerPath
+    process.env.AGENT_RELAY_BIN = cliPath
+    const manager = new BrokerManager()
+
+    try {
+      await manager.start(PROJECT_ID, '/tmp/project-1', 'pear-project-1', undefined as never, [])
+
+      const spawnOptions = mock.HarnessDriverClient.spawn.mock.calls[0]?.[0] as {
+        env?: NodeJS.ProcessEnv
+      } | undefined
+      expect(spawnOptions?.env?.BROKER_BINARY_PATH).toBe(brokerPath)
+      expect(spawnOptions?.env?.AGENT_RELAY_BIN).toBe(cliPath)
+    } finally {
+      await manager.shutdown()
+      await rm(tempDir, { recursive: true, force: true })
+    }
+  })
+
   it('reads the local broker workspace key for cloud provisioning', async () => {
     const manager = new BrokerManager()
     const local = await startLocal(manager)

src/main/broker.ts

@@ -1491,13 +1491,13 @@ export class BrokerManager {
         env: {
           PATH: augmentedPath(),
           ...brokerBinary.env,
-          // Spawned workers inherit the broker's env. AGENT_RELAY_BIN is the
-          // ecosystem-standard broker-binary override (harness-driver
-          // broker-path, workforce runtime relay-mcp); it lets the workforce
-          // CLI's `mcp-args --register` relay-MCP injection find the same
-          // broker binary Pear runs — a PATH lookup fails in packaged
-          // installs and can hit a version-skewed global binary in dev.
-          AGENT_RELAY_BIN: brokerBinary.realBinaryPath,
+          // Spawned workers inherit the broker's env. Keep the native broker
+          // on its unambiguous override: Relayfile separately defines
+          // AGENT_RELAY_BIN as the external Agent Relay CLI that owns cloud
+          // session refresh. Passing the broker there makes delegated-token
+          // re-mint execute `agent-relay-broker cloud session` and fail.
+          BROKER_BINARY_PATH: brokerBinary.realBinaryPath,
+          ...(brokerBinary.agentRelayCLIPath ? { AGENT_RELAY_BIN: brokerBinary.agentRelayCLIPath } : {}),
           ...(agentRelayMcpCommand ? { AGENT_RELAY_MCP_COMMAND: agentRelayMcpCommand } : {})
         },
         onStderr: (line: string) => {