# R11 — Success within answer margin

Environment: fs-50; Linux 6.8.0-117-generic x86_64; Node v26.12.1; Playwright 1.60.0; Chrome Headless Shell 157.0.8103.38; isolated dev:server, T3CODE_DEV_SEED=0, fresh per-checkout SQLite; synthetic Fx fixture; RPC/MCP over loopback; UTC timestamps.

Scripted interaction (same inputs on both revisions; generated ids differ): Delay dark emulateMedia by 15100ms against the public 15000ms budget, then status and evaluate.

What differed: Both revisions return successful appearance. The head still accepts real success after its signal expired but within the 500ms answer margin.

## C2 steps and timestamps

Before step times (UTC):

```jsonl
{"time":"2026-11-10T11:32:14.640Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:32:14.728Z","tool":"preview_set_appearance","caller":0,"args":{"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","colorScheme":"dark"}}
{"time":"2026-11-10T11:32:32.047Z","tool":"preview_status","caller":0,"args":{"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480"}}
{"time":"2026-11-10T11:32:32.072Z","tool":"preview_evaluate","caller":0,"args":{"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","expression":"document.body.dataset.probe=\"ok\"; \"ok\""}}
{"time":"2026-11-10T11:32:32.108Z","tool":"t3_preview_close","caller":0,"args":{"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480"}}
```

After step times (UTC):

```jsonl
{"time":"2026-11-10T11:31:26.042Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:31:26.173Z","tool":"preview_set_appearance","caller":0,"args":{"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","colorScheme":"dark"}}
{"time":"2026-11-10T11:31:43.404Z","tool":"preview_status","caller":0,"args":{"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}}
{"time":"2026-11-10T11:31:43.414Z","tool":"preview_evaluate","caller":0,"args":{"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","expression":"document.body.dataset.probe=\"ok\"; \"ok\""}}
{"time":"2026-11-10T11:31:43.427Z","tool":"t3_preview_close","caller":0,"args":{"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}}
```

<a id="before"></a>
## Before — C2

SHA: [fa2f4ff2a2](https://github.com/pingdotgg/t3code/commit/fa2f4ff2a2bac5ac92e07749f6b83b0003d642a0)

Agent-visible results (status/list fields selected; error text verbatim):

```jsonl
{"time":"2026-11-10T11:32:14.723Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","url":null,"loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:32:29.891Z","tool":"preview_set_appearance","caller":0,"result":{"isError":false,"structuredContent":{"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","colorScheme":"dark"}}}
{"time":"2026-11-10T11:32:32.070Z","tool":"preview_status","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","url":null,"loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:32:32.107Z","tool":"preview_evaluate","caller":0,"result":{"isError":false,"structuredContent":{"value":"ok"}}}
{"time":"2026-11-10T11:32:32.133Z","tool":"t3_preview_close","caller":0,"result":{"isError":false,"structuredContent":{}}}
```

Relevant server milestones:

```jsonl
{"time":"2026-11-10T11:31:22.851Z","event":"host.connected","connectionId":"bb0cd425-09b7-4a2b-a500-62416afd6798"}
{"time":"2026-11-10T11:31:54.934Z","event":"host.connected","connectionId":"746164df-43f7-443a-b8a2-62c5ea4dfe2c"}
{"time":"2026-11-10T11:32:13.712Z","event":"host.connected","connectionId":"c8993c19-f16f-4c48-a9be-fb75b6d77a37"}
{"time":"2026-11-10T11:32:14.647Z","event":"request.start","operation":"open","requestId":"preview-58","tabId":"tab_6_bea12b60-c14f-4580-bb58-2b38123bd480","timeoutMs":660000,"connectionId":"c8993c19-f16f-4c48-a9be-fb75b6d77a37"}
{"time":"2026-11-10T11:32:14.707Z","tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","event":"tab.created","detail":{"desktop":false,"isolatedContext":true}}
{"time":"2026-11-10T11:32:14.750Z","event":"request.start","operation":"setColorScheme","requestId":"preview-59","tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","timeoutMs":15000,"connectionId":"c8993c19-f16f-4c48-a9be-fb75b6d77a37"}
{"time":"2026-11-10T11:32:14.752Z","tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","event":"emulateMedia.start","detail":[{"colorScheme":"dark"}]}
{"time":"2026-11-10T11:32:29.875Z","tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","event":"emulateMedia.end","detail":{}}
{"time":"2026-11-10T11:32:32.058Z","event":"request.start","operation":"status","requestId":"preview-61","tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","timeoutMs":15000,"connectionId":"c8993c19-f16f-4c48-a9be-fb75b6d77a37"}
{"time":"2026-11-10T11:32:32.093Z","event":"request.start","operation":"evaluate","requestId":"preview-62","tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","timeoutMs":15000,"connectionId":"c8993c19-f16f-4c48-a9be-fb75b6d77a37"}
{"time":"2026-11-10T11:32:32.125Z","event":"request.start","operation":"close","requestId":"preview-64","tabId":"tab_7_bea12b60-c14f-4580-bb58-2b38123bd480","timeoutMs":15000,"connectionId":"c8993c19-f16f-4c48-a9be-fb75b6d77a37"}
```

<a id="after"></a>
## After — C2

SHA: [b088b88d19](https://github.com/pingdotgg/t3code/commit/b088b88d19fb0edc43f754da2e1d199bda70d6d8)

Agent-visible results (status/list fields selected; error text verbatim):

```jsonl
{"time":"2026-11-10T11:31:26.171Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","url":null,"loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:31:41.302Z","tool":"preview_set_appearance","caller":0,"result":{"isError":false,"structuredContent":{"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","colorScheme":"dark"}}}
{"time":"2026-11-10T11:31:43.413Z","tool":"preview_status","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","url":null,"loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:31:43.427Z","tool":"preview_evaluate","caller":0,"result":{"isError":false,"structuredContent":{"value":"ok"}}}
{"time":"2026-11-10T11:31:44.721Z","tool":"t3_preview_close","caller":0,"result":{"isError":false,"structuredContent":{}}}
```

Relevant server milestones:

```jsonl
{"time":"2026-11-10T11:29:29.949Z","event":"host.connected","connectionId":"09b81d2d-300e-436a-8035-a1f18530f0d1"}
{"time":"2026-11-10T11:31:26.061Z","event":"request.start","operation":"open","requestId":"preview-43","tabId":"tab_5_bd9d2d9d-727d-4676-b1e8-9554a31f1406","timeoutMs":660000,"connectionId":"09b81d2d-300e-436a-8035-a1f18530f0d1"}
{"time":"2026-11-10T11:31:26.159Z","tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"tab.created","detail":{"desktop":false,"isolatedContext":true}}
{"time":"2026-11-10T11:31:26.192Z","event":"request.start","operation":"setColorScheme","requestId":"preview-44","tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","timeoutMs":15000,"connectionId":"09b81d2d-300e-436a-8035-a1f18530f0d1"}
{"time":"2026-11-10T11:31:26.193Z","tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"emulateMedia.start","detail":[{"colorScheme":"dark"}]}
{"time":"2026-11-10T11:31:41.298Z","tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"emulateMedia.end","detail":{}}
{"time":"2026-11-10T11:31:43.410Z","event":"request.start","operation":"status","requestId":"preview-46","tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","timeoutMs":15000,"connectionId":"09b81d2d-300e-436a-8035-a1f18530f0d1"}
{"time":"2026-11-10T11:31:43.422Z","event":"request.start","operation":"evaluate","requestId":"preview-47","tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","timeoutMs":15000,"connectionId":"09b81d2d-300e-436a-8035-a1f18530f0d1"}
{"time":"2026-11-10T11:31:43.438Z","event":"request.start","operation":"close","requestId":"preview-49","tabId":"tab_6_bd9d2d9d-727d-4676-b1e8-9554a31f1406","timeoutMs":15000,"connectionId":"09b81d2d-300e-436a-8035-a1f18530f0d1"}
```

AI-assisted; verified with the tests and tools listed above.