# Runtime transcript for pingdotgg/t3code#26864

Fresh dev server (`T3CODE_DEV_SEED=0 vp run dev`) on a Linux VM, Claude provider (claude-sonnet-5-5), server preview runtime (headless).
Test page: a local static page that starts an AudioContext oscillator, served on http://localhost:5199/.
To reach the reporter's lifecycle in minutes, the repro checkout's `DEFAULT_IDLE_TIMEOUT_MS` (ProviderSessionManager.ts) was lowered from 30 min to 60 s. That local edit is not part of the PR.
Threads were driven with `node apps/server/src/bin.ts thread start|send --wait --json`.

## Before (origin/main f855f016b3)

### Attempt 1: reporter's steps literally (native Agent-tool subagent opens the tab, main agent closes it, one session)
The subagent opened the tab and took the snapshot. I then closed the tab myself.

- **tabId:** `tab_1_0a00c3fe-cf4f-4e2b-95e3-5b3d153a1f93`
- **Page title:** `preview_open` returned "Audio game". The snapshot later showed "Audio game suspended 0.0".
- **Page content:** one "Audio game" heading and no interactive elements. The page loaded with HTTP 200.
- **Console warning:** "The AudioContext was not allowed to start. It must be resumed (or created) after a user gesture on the page. https://developer.chrome.com/blog/autoplay/#web_audio"
- **`t3_preview_close` result:** `{}`. There was no error text.

Result: no error. Native subagents share the main agent's MCP credential, so the bug needs a credential rotation in between.

### Attempt 2, turn 1: open a hidden tab
tabId: tab_1_3a1230c7-f9c2-4c6d-ae8d-6709bfcd74ee
ownedByCaller: true

### Attempt 2, turn 2: about 90 s later, after the idle stop, the same thread closes it
**t3_preview_list entry** for `tab_1_3a1230c7-f9c2-4c6d-ae8d-6709bfcd74ee`, verbatim:

```json
{"threadId":"mcp:8941e595-efdf-4b8a-af1c-a2f1ed43ba0c","tabId":"tab_1_3a1230c7-f9c2-4c6d-ae8d-6709bfcd74ee","navStatus":{"_tag":"Success","url":"http://localhost:5199/","title":"Audio game"},"canGoBack":true,"canGoForward":false,"viewport":{"_tag":"fill"},"runtime":"server","automationOwner":"0b5349b2-11b7-45fd-a80d-c8fb90ae8b86\u00000703e45a-987a-40db-bd7a-6f1227383162\u0000mcp:8941e595-efdf-4b8a-af1c-a2f1ed43ba0c","reveal":false,"updatedAt":"2026-10-29T08:22:45.124Z"}
```

The entry has no `owner`, `ownedByCaller` or `visible` fields. The closest equivalents are `automationOwner` (shown above) and `reveal: false`.

**t3_preview_close** failed. The full error text, verbatim:

```json
{"_tag":"PreviewAutomationControlInterruptedError","operation":"close","environmentId":"0b5349b2-11b7-45fd-a80d-c8fb90ae8b86","threadId":"mcp:8941e595-efdf-4b8a-af1c-a2f1ed43ba0c","providerSessionId":"13c9e917-c8bb-4c31-9730-924c8702b2ec","providerInstanceId":"claudeAgent","clientId":"server-browser","connectionId":"d6397636-56fb-4a6f-ba81-e93525683299","requestId":"preview-1","tabId":"tab_1_3a1230c7-f9c2-4c6d-ae8d-6709bfcd74ee","timeoutMs":15000,"remoteTag":"PreviewAutomationControlInterruptedError","remoteMessageLength":89,"remoteDetailKind":"string","cause":{"_tag":"PreviewAutomationControlInterruptedError","message":"This tab belongs to another agent session. You can read it, but open your own tab to act.","detail":"agentMismatch"},"reason":"agentMismatch"}
```

The tab is still open. I didn't retry or open any other tab.

This conflicts with my earlier answer. `preview_open` reported `ownedByCaller: true` for this tab, but `close` rejected it as belonging to another agent session (`agentMismatch`).

### Attempt 3: a different thread tries to close the same tab
The `t3_preview_close` call for tab `tab_1_3a1230c7-f9c2-4c6d-ae8d-6709bfcd74ee` returned `{}`. It gave no error.

Check from the original thread afterwards:
- `tab_1_3a1230c7-f9c2-4c6d-ae8d-6709bfcd74ee`: "Audio game"

## After (fix/issue-26864 b158e55db2 applied)

### Turn 1: open a hidden tab
tabId: tab_1_f9fc247e-cb90-4cd2-a494-968331f7ba58
ownedByCaller: true

### Turn 2: after the idle stop, the same thread evaluates (still refused) then closes (succeeds)
1. **`t3_preview_list` automationOwner** for `tab_1_f9fc247e-cb90-4cd2-a494-968331f7ba58`, verbatim: `0b5349b2-11b7-45fd-a80d-c8fb90ae8b86\u00004be925a6-34e0-4746-a69a-fa86d74b4a5f\u0000mcp:1e44bde6-b13d-468e-b1e8-dd7385d19843`
2. **`preview_evaluate`** with `document.title` failed with this error: `This browser tab belongs to another agent session or a human. Open your own tab.` I didn't retry.
3. **`t3_preview_close`** returned `{}`, with no error.
4. **Second `t3_preview_list`** returned an empty `sessions` array, so it lists no tabIds. The `revision` went from 3 to 4.