test: keep review assertions tied to real failure paths

CodeRabbit flagged three non-blocking but valid review gaps: platform-specific mailbox errno checks, brittle UDS connection-failure message assertions, and missing AgentSummary reschedule proof after fork errors. This keeps the fixes narrow by tightening the affected assertions and adding a structured UDS connection error for tests to assert behavior instead of prose.

Constraint: PR #374 is a review follow-up and must not hide warnings, skip tests, or merge the PR.

Rejected: Matching the UDS failure message literal | preserves the brittle coupling CodeRabbit flagged.

Rejected: Asserting only that mailbox writes throw | would allow unrelated pre-path failures to pass.

Confidence: high

Scope-risk: narrow

Directive: Keep UDS connection-failure tests on structured error data, not display wording.

Tested: bun test src/services/AgentSummary/__tests__/agentSummary.test.ts src/utils/__tests__/teammateMailbox.test.ts src/utils/__tests__/udsMessaging.test.ts

Tested: bunx tsc --noEmit --pretty false

Tested: bun run lint

Tested: bun run test:all

Tested: bun test --coverage --coverage-reporter lcov --coverage-dir coverage

Tested: bun run build

Tested: bun run build:vite

Not-tested: GitHub-hosted CodeRabbit refresh until pushed.

src/utils/__tests__/teammateMailbox.test.ts

@@ -1,9 +1,10 @@
 import { afterEach, beforeEach, describe, expect, test } from 'bun:test'
-import { mkdir, readFile, rm, writeFile } from 'node:fs/promises'
+import { mkdir, readFile, rm, stat, writeFile } from 'node:fs/promises'
 import { mkdtempSync } from 'node:fs'
 import { tmpdir } from 'node:os'
 import { dirname, join } from 'node:path'
 import type { Message } from 'src/types/message.js'
+import { getErrnoCode } from 'src/utils/errors.js'
 import {
   compactMailboxMessages,
   getLastPeerDmSummary,
@@ -356,10 +357,16 @@ describe('teammate mailbox retention', () => {
       'alpha',
     ).then(
       () => undefined,
-      error => error as NodeJS.ErrnoException,
+      err => err,
     )
 
-    expect(error?.code).toBe('EISDIR')
+    const code = getErrnoCode(error)
+    expect(code).toBeDefined()
+    if (code === undefined) {
+      throw new Error('Expected filesystem errno code')
+    }
+    expect(['EISDIR', 'EPERM', 'EACCES']).toContain(code)
+    expect((await stat(inboxPath)).isDirectory()).toBe(true)
   })
 
   test('readMailbox fails closed on corrupt mailbox content', async () => {

src/utils/__tests__/udsMessaging.test.ts

@@ -227,11 +227,20 @@ describe('UDS inbox retention', () => {
       JSON.stringify({ socketPath: path, authToken: 'test-token' }),
       'utf-8',
     )
-    const { sendToUdsSocket } = await import('../udsClient.js')
-
-    await expect(sendToUdsSocket(path, 'hello')).rejects.toThrow(
-      'Failed to connect to peer',
+    const { sendToUdsSocket, UdsPeerConnectionError } = await import(
+      '../udsClient.js'
     )
+
+    const error = await sendToUdsSocket(path, 'hello').then(
+      () => undefined,
+      err => err,
+    )
+    expect(error).toBeInstanceOf(UdsPeerConnectionError)
+    if (!(error instanceof UdsPeerConnectionError)) {
+      throw new Error('Expected UDS peer connection error')
+    }
+    expect(error.socketPath).toBe(path)
+    expect(error.message).not.toContain('test-token')
   })
 
   test('sendUdsMessage fails closed before connecting without an auth token', async () => {