Issue 16808 after-runtime proof, 2026-10-22

Source: fac85cd6d2; base: 8d3b061121

Real app: isolated .t3, backend source via vp exec node src/bin.ts (no watch), vp run dev:web; ports 15653/7613.

Ubuntu Linux x64; collaborative browser 1280x800, no emulation; Claude Opus 5.5 medium, full access.

Same synthetic prompt as before: native Agent(run_in_background:true), sleep20, delegate_task to codex/gpt-6.1-sol with task Reply exactly OK; root replies ROOT_STARTED and ends.

Root after run:

(3, 'completed', '2026-10-22T10:34:59.971Z', '2026-10-22T10:35:06.418Z')

(4, 'completed', '2026-10-22T10:35:36.853Z', '2026-10-22T10:35:40.777Z')

(5, 'completed', '2026-10-22T10:35:40.771Z', '2026-10-22T10:35:47.071Z')

Native background subagent raw result:

I ran `sleep 20`, then called `mcp__t3-code__delegate_task`. The call was accepted. The child task is running on codex with `gpt-6.1-sol` and has not replied yet. Raw tool result:

```json
{"taskId":"node:delegated-task:command%3Amcp%3Aab584eb2-34d0-4cfe-80cb-053facd7abcb%3Adelegate-task%3Aissue16808-dev-after","childThreadId":"thread:delegated-task:command%3Amcp%3Aab584eb2-34d0-4cfe-80cb-053facd7abcb%3Adelegate-task%3Aissue16808-dev-after","childRunId":"run:thread:thread%3Adelegated-task%3Acommand%253Amcp%253Aab584eb2-34d0-4cfe-80cb-053facd7abcb%253Adelegate-task%253Aissue16808-dev-after:ordinal:1","childNodeId":"node:delegated-task:command%3Amcp%3Aab584eb2-34d0-4cfe-80cb-053facd7abcb%3Adelegate-task%3Aissue16808-dev-after","status":"running","workState":"working","hasPendingChildRuns":false,"latestTerminalRunId":null,"latestTerminalStatus":null,"latestTerminalSummary":null,"latestTerminalResultContextTransferId":null,"providerInstanceId":"codex","model":"gpt-6.1-sol","options":[],"summary":null,"resultContextTransferId":null,"hasPendingQuestion":false,"pendingApproval":null,"waitTimedOut":false}
```

Persisted delegated task (exactly one):

{
  "id": "node:delegated-task:command%3Amcp%3Aab584eb2-34d0-4cfe-80cb-053facd7abcb%3Adelegate-task%3Aissue16808-dev-after",
  "threadId": "5e3c9aae-acf4-47b6-b2b1-95ff7399f78f",
  "runId": "run:thread:5e3c9aae-acf4-47b6-b2b1-95ff7399f78f:ordinal:3",
  "parentNodeId": "node:run:run%3Athread%3A5e3c9aae-acf4-47b6-b2b1-95ff7399f78f%3Aordinal%3A3:root",
  "childThreadId": "thread:delegated-task:command%3Amcp%3Aab584eb2-34d0-4cfe-80cb-053facd7abcb%3Adelegate-task%3Aissue16808-dev-after",
  "origin": "app_owned",
  "providerInstanceId": "codex",
  "model": "gpt-6.1-sol",
  "status": "completed",
  "result": "OK",
  "completionDelivery": {
    "state": "delivered",
    "observedByRunId": null
  },
  "startedAt": "2026-10-22T10:35:32.433Z",
  "completedAt": "2026-10-22T10:35:36.798Z"
}

Observed parent web transcript:

On the patched server, the background subagent's delegate_task call succeeded and Codex finished the job. The delegated task (clientRequestId issue16808-dev-after) reported [completed] and returned exactly: OK.

The parent received the delegated completion before the native subagent notification arrived; it later reported the raw native tool result. These are two distinct notifications, one delegated task.

Visible render fixture matrix: empty. No render path changed.

Before proof: issue-16808-before.txt.