test: keep Codecov coverage on real agent communication paths (#374)

* test: keep Codecov coverage on real agent communication paths

PR #369 was merged before the final Codecov coverage fix landed, so this follow-up carries only the incremental real-path tests needed on top of main. The tests exercise AgentSummary lifecycle branches, mailbox fail-closed behavior, UDS client connection failure through a real capability file, and UDS response-reader framing without mock.module, warning suppression, feature fallback, or production-code churn.

Constraint: PR #369 is already merged; this branch must contain only the incremental Codecov repair on top of latest main

Rejected: Reopen or keep pushing the merged PR branch | merged PR refs do not update and would leave Codecov stale

Rejected: Mock bun:bundle or hide warnings | would reintroduce cross-test pollution and pseudo coverage

Rejected: Keep unrelated SendMessageTool production diff | it created avoidable patch-coverage debt without improving the runtime path

Confidence: high

Scope-risk: narrow

Directive: Keep these coverage tests on real paths; do not replace them with output suppression or feature-flag mocks

Tested: bunx tsc --noEmit --pretty false

Tested: bun run lint

Tested: bun test src\utils\__tests__\teammateMailbox.test.ts

Tested: bun test src\services\AgentSummary\__tests__\agentSummary.test.ts src\services\AgentSummary\__tests__\summaryContext.test.ts src\utils\__tests__\teammateMailbox.test.ts src\utils\__tests__\udsMessaging.test.ts src\utils\__tests__\udsResponseReader.test.ts packages\builtin-tools\src\tools\SendMessageTool\__tests__\udsRecipientSanitization.test.ts

Tested: bun run test:all

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

Tested: bun run build

Tested: bun run build:vite

Tested: bun audit

Tested: git diff --check

Tested: Claude simplify review GO (.omx/artifacts/claude-simplify-codecov-20260427-1521.md)

Tested: Claude security review GO (.omx/artifacts/claude-security-codecov-20260427-1522.md)

Not-tested: GitHub-hosted Codecov upload after this amended commit until PR checks rerun

* 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.

* test: remove brittle review follow-up assumptions

CodeRabbit's second pass found two valid brittleness issues and one suggested callback-reference assertion that would not match production behavior. This keeps the production behavior unchanged: timers still schedule the summarizer closure, tests now assert timer-handle identity, and UDS connection errors use native Error.cause instead of shadowing it.

Constraint: Do not manufacture behavior just to satisfy a review hint; assertions must match the real AgentSummary scheduling contract.

Rejected: Assert a fresh scheduled callback function | scheduleNext intentionally passes the same runSummary closure each time.

Rejected: Store a custom cause field on UdsPeerConnectionError | native Error.cause is available under ESNext/Bun.

Confidence: high

Scope-risk: narrow

Directive: Timer tests should assert returned handle identity for ownership, not incidental numeric values.

Tested: bun test src/services/AgentSummary/__tests__/agentSummary.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.

* test: enforce structured UDS timeout failures

CodeRabbit's follow-up surfaced a real consistency gap: UDS send socket errors used UdsPeerConnectionError while response timeouts still rejected a generic Error. Timeouts now use the same structured peer failure contract, and the test exercises that path through a short explicit timeout instead of waiting for the production default.

The AgentSummary unchanged-fingerprint test now also asserts that the second unchanged tick does not log errors, preserving the existing behavior checks without changing production scheduling semantics.

Constraint: Keep the production timeout default at 5000ms while allowing tests to exercise the timeout path quickly.

Rejected: Leave timeout failures as generic Error | callers would need separate handling for the same peer connection failure class.

Confidence: high

Scope-risk: narrow

Directive: Keep UDS send timeout and socket-error branches on the same structured error contract.

Tested: bun test src/services/AgentSummary/__tests__/agentSummary.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.

---------

Co-authored-by: unraid <local@unraid.local>

src/utils/udsClient.ts

@@ -36,6 +36,19 @@ export type PeerSession = {
   alive: boolean
 }
 
+export class UdsPeerConnectionError extends Error {
+  readonly socketPath: string
+
+  constructor(socketPath: string, cause: unknown) {
+    super(
+      `Failed to connect to peer at ${socketPath}: ${errorMessage(cause)}`,
+      { cause },
+    )
+    this.name = 'UdsPeerConnectionError'
+    this.socketPath = socketPath
+  }
+}
+
 // ---------------------------------------------------------------------------
 // Session directory
 // ---------------------------------------------------------------------------
@@ -193,6 +206,7 @@ export async function isPeerAlive(
 export async function sendToUdsSocket(
   targetSocketPath: string,
   message: string | Record<string, unknown>,
+  timeoutMs = 5000,
 ): Promise<void> {
   const { parseUdsTarget } = await import('./udsMessaging.js')
   const target = parseUdsTarget(targetSocketPath)
@@ -237,12 +251,15 @@ export async function sendToUdsSocket(
       maxFrameBytes: MAX_UDS_FRAME_BYTES,
       onSettled: finish,
       formatSocketError: err =>
-        new Error(
-          `Failed to connect to peer at ${target.socketPath}: ${errorMessage(err)}`,
-        ),
+        new UdsPeerConnectionError(target.socketPath, err),
     })
-    conn.setTimeout(5000, () => {
-      finish(new Error('Connection timed out'))
+    conn.setTimeout(timeoutMs, () => {
+      finish(
+        new UdsPeerConnectionError(
+          target.socketPath,
+          new Error('Connection timed out'),
+        ),
+      )
     })
   })
 }