# R24 — Cross-tab zoom

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): With A held, manager-adjust headless B zoom to 1.25 and repeat; inspect effective dimensions and CDP device metrics. Repeat against a real Electron WebContents attached through the scratch desktop CDP binding; set native zoom 1.25 and verify no backend override.

What differed: Headless after applies zoom before A releases; before waits. Equal zoom emits no second metrics override. A real Electron WebContents fixture also applies native zoom 1.25; both revisions skip backend device-metrics/viewport zoom on its desktop-attached page, including after A releases.

## C5 steps and timestamps

Before step times (UTC):

```jsonl
{"time":"2026-11-10T11:39:21.061Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:39:21.141Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:39:21.215Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:39:21.288Z","tool":"preview_navigate","caller":0,"args":{"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","url":"http://127.0.0.1:18766/fixture"}}
{"time":"2026-11-10T11:39:21.421Z","tool":"preview_set_appearance","caller":0,"args":{"tabId":"tab_d_bea12b60-c14f-4580-bb58-2b38123bd480","colorScheme":"dark"}}
{"time":"2026-11-10T11:39:38.940Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"f41bc889-9c75-40ee-b7a0-6866bd924e3e","tabId":"tab_d_bea12b60-c14f-4580-bb58-2b38123bd480","colorScheme":"light"}}
{"time":"2026-11-10T11:39:39.588Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"f41bc889-9c75-40ee-b7a0-6866bd924e3e","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","zoomFactor":1.25}}
{"time":"2026-11-10T11:39:39.894Z","tool":"preview_evaluate","caller":0,"args":{"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","expression":"({width:innerWidth,height:innerHeight})"}}
{"time":"2026-11-10T11:39:39.917Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"f41bc889-9c75-40ee-b7a0-6866bd924e3e","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","zoomFactor":1.25}}
{"time":"2026-11-10T11:39:42.055Z","event":"gate.release","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","mode":"resolve"}
{"time":"2026-11-10T11:39:43.271Z","event":"release.stuck.A"}
{"time":"2026-11-10T11:39:43.272Z","event":"gate.release","tabId":"tab_d_bea12b60-c14f-4580-bb58-2b38123bd480","mode":"resolve"}
```

After step times (UTC):

```jsonl
{"time":"2026-11-10T11:36:55.056Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:36:55.139Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:36:55.197Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:36:55.262Z","tool":"preview_navigate","caller":0,"args":{"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","url":"http://127.0.0.1:18766/fixture"}}
{"time":"2026-11-10T11:36:55.471Z","tool":"preview_set_appearance","caller":0,"args":{"tabId":"tab_c_bd9d2d9d-727d-4676-b1e8-9554a31f1406","colorScheme":"dark"}}
{"time":"2026-11-10T11:37:12.494Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"100ee364-0c8a-4d22-8790-3614885b473c","tabId":"tab_c_bd9d2d9d-727d-4676-b1e8-9554a31f1406","colorScheme":"light"}}
{"time":"2026-11-10T11:37:13.150Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"100ee364-0c8a-4d22-8790-3614885b473c","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","zoomFactor":1.25}}
{"time":"2026-11-10T11:37:13.460Z","tool":"preview_evaluate","caller":0,"args":{"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","expression":"({width:innerWidth,height:innerHeight})"}}
{"time":"2026-11-10T11:37:13.487Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"100ee364-0c8a-4d22-8790-3614885b473c","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","zoomFactor":1.25}}
{"time":"2026-11-10T11:37:15.634Z","event":"gate.release","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","mode":"resolve"}
{"time":"2026-11-10T11:37:16.850Z","event":"release.stuck.A"}
{"time":"2026-11-10T11:37:16.850Z","event":"gate.release","tabId":"tab_c_bd9d2d9d-727d-4676-b1e8-9554a31f1406","mode":"resolve"}
```

<a id="before"></a>
<a id="before-c5"></a>
## Before — C5

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

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

```jsonl
{"time":"2026-11-10T11:39:21.140Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_d_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_d_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:39:21.215Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_e_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_d_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true},{"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:39:21.288Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_f_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_d_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true},{"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true},{"tabId":"tab_f_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:39:21.420Z","tool":"preview_navigate","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","url":"http://127.0.0.1:18766/fixture","loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_d_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true},{"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true},{"tabId":"tab_f_bea12b60-c14f-4580-bb58-2b38123bd480","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:39:37.438Z","tool":"preview_set_appearance","caller":0,"result":{"content":[{"type":"text","text":"Preview automation setColorScheme timed out after 15000ms."}],"isError":true}}
{"time":"2026-11-10T11:39:39.916Z","tool":"preview_evaluate","caller":0,"result":{"isError":false,"structuredContent":{"toolIcon":{"_tag":"website","pageUrl":"http://127.0.0.1:18766/fixture"},"value":{"width":1280,"height":800}}}}
{"time":"2026-11-10T11:39:39.594Z","event":"RPC.result","method":"preview.adjust","result":{"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","viewport":{"_tag":"freeform","width":800,"height":600},"zoomFactor":1.25}}
{"time":"2026-11-10T11:39:39.922Z","event":"RPC.result","method":"preview.adjust","result":{"tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","viewport":{"_tag":"freeform","width":800,"height":600},"zoomFactor":1.25}}
```

Relevant server milestones:

```jsonl
{"time":"2026-11-10T11:37:01.802Z","event":"host.connected","connectionId":"df66ae07-3409-4a36-adf5-acca7ed48f60"}
{"time":"2026-11-10T11:39:21.310Z","event":"mirror.received","type":"navigated","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:21.416Z","event":"mirror.received","type":"navigated","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:38.436Z","event":"host.connected","connectionId":"a4ed59d2-1007-4877-9053-374f3fd9a6d0"}
{"time":"2026-11-10T11:39:43.283Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.287Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.287Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.287Z","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","event":"cdp.start","detail":{"method":"Emulation.setDeviceMetricsOverride","params":{"width":640,"height":480,"deviceScaleFactor":2.5,"mobile":false}}}
{"time":"2026-11-10T11:39:43.288Z","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","event":"cdp.end","detail":{"method":"Emulation.setDeviceMetricsOverride"}}
{"time":"2026-11-10T11:39:43.288Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.288Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.294Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.298Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.303Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.303Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.318Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.319Z","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","event":"cdp.start","detail":{"method":"Emulation.setDeviceMetricsOverride","params":{"width":720,"height":560,"deviceScaleFactor":2.5,"mobile":false}}}
{"time":"2026-11-10T11:39:43.320Z","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","event":"cdp.end","detail":{"method":"Emulation.setDeviceMetricsOverride"}}
{"time":"2026-11-10T11:39:43.320Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.321Z","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","event":"cdp.start","detail":{"method":"Emulation.setDeviceMetricsOverride","params":{"width":600,"height":467,"deviceScaleFactor":3,"mobile":false}}}
{"time":"2026-11-10T11:39:43.322Z","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480","event":"cdp.end","detail":{"method":"Emulation.setDeviceMetricsOverride"}}
{"time":"2026-11-10T11:39:43.322Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.706Z","event":"mirror.received","type":"navigated","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.706Z","event":"mirror.received","type":"navigated","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.706Z","event":"mirror.received","type":"navigated","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.706Z","event":"mirror.received","type":"navigated","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:43.706Z","event":"mirror.received","type":"navigated","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:45.299Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
{"time":"2026-11-10T11:39:45.604Z","event":"mirror.received","type":"resized","tabId":"tab_e_bea12b60-c14f-4580-bb58-2b38123bd480"}
```

<a id="after"></a>
<a id="after-c5"></a>
## After — C5

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

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

```jsonl
{"time":"2026-11-10T11:36:55.139Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_c_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_c_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:36:55.197Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_d_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_c_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true},{"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:36:55.261Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_e_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_c_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true},{"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true},{"tabId":"tab_e_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:36:55.469Z","tool":"preview_navigate","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","url":"http://127.0.0.1:18766/fixture","loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_c_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true},{"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true},{"tabId":"tab_e_bd9d2d9d-727d-4676-b1e8-9554a31f1406","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:37:10.993Z","tool":"preview_set_appearance","caller":0,"result":{"content":[{"type":"text","text":"Preview automation setColorScheme timed out after 15000ms."}],"isError":true}}
{"time":"2026-11-10T11:37:13.487Z","tool":"preview_evaluate","caller":0,"result":{"isError":false,"structuredContent":{"toolIcon":{"_tag":"website","pageUrl":"http://127.0.0.1:18766/fixture"},"value":{"width":640,"height":480}}}}
{"time":"2026-11-10T11:37:13.158Z","event":"RPC.result","method":"preview.adjust","result":{"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","viewport":{"_tag":"freeform","width":800,"height":600},"zoomFactor":1.25}}
{"time":"2026-11-10T11:37:13.495Z","event":"RPC.result","method":"preview.adjust","result":{"tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","viewport":{"_tag":"freeform","width":800,"height":600},"zoomFactor":1.25}}
```

Relevant server milestones:

```jsonl
{"time":"2026-11-10T11:29:29.949Z","event":"host.connected","connectionId":"09b81d2d-300e-436a-8035-a1f18530f0d1"}
{"time":"2026-11-10T11:36:55.287Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:36:55.463Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:12.518Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:12.847Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:13.154Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:13.155Z","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"cdp.start","detail":{"method":"Emulation.setDeviceMetricsOverride","params":{"width":640,"height":480,"deviceScaleFactor":2.5,"mobile":false}}}
{"time":"2026-11-10T11:37:13.159Z","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"cdp.end","detail":{"method":"Emulation.setDeviceMetricsOverride"}}
{"time":"2026-11-10T11:37:13.492Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:13.799Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:13.808Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:13.841Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:14.165Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:14.174Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:14.191Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:14.501Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:14.809Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:15.113Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:15.318Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:15.322Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:15.324Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:15.657Z","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"cdp.start","detail":{"method":"Emulation.setDeviceMetricsOverride","params":{"width":720,"height":560,"deviceScaleFactor":2.5,"mobile":false}}}
{"time":"2026-11-10T11:37:15.658Z","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"cdp.end","detail":{"method":"Emulation.setDeviceMetricsOverride"}}
{"time":"2026-11-10T11:37:15.660Z","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"cdp.start","detail":{"method":"Emulation.setDeviceMetricsOverride","params":{"width":600,"height":467,"deviceScaleFactor":3,"mobile":false}}}
{"time":"2026-11-10T11:37:15.661Z","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406","event":"cdp.end","detail":{"method":"Emulation.setDeviceMetricsOverride"}}
{"time":"2026-11-10T11:37:15.667Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:15.690Z","event":"mirror.received","type":"navigated","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:18.877Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
{"time":"2026-11-10T11:37:19.186Z","event":"mirror.received","type":"resized","tabId":"tab_d_bd9d2d9d-727d-4676-b1e8-9554a31f1406"}
```

## C24native steps and timestamps

Native fixture: Electron 44.10.1 / Chromium 152.0.7977.169; direct scratch desktop CDP binding, real WebContents native zoom.

Before step times (UTC):

```jsonl
{"time":"2026-11-10T11:45:33.642Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:45:35.399Z","event":"RPC.send","method":"preview.open","payload":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","url":"http://127.0.0.1:18766/desktop-fixture","runtime":"server","reveal":false}}
{"time":"2026-11-10T11:45:36.424Z","tool":"preview_status","caller":0,"args":{"tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}}
{"time":"2026-11-10T11:45:36.424Z","event":"native.state","route":"/zoom/1","result":{"width":1000,"height":673,"zoomFactor":1,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:36.440Z","tool":"preview_set_appearance","caller":0,"args":{"tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","colorScheme":"dark"}}
{"time":"2026-11-10T11:45:53.955Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","colorScheme":"light"}}
{"time":"2026-11-10T11:45:53.966Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","zoomFactor":1.25}}
{"time":"2026-11-10T11:45:53.976Z","event":"native.state","route":"/zoom/1.25","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:54.277Z","tool":"preview_evaluate","caller":0,"args":{"tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","expression":"({width:innerWidth,height:innerHeight})"}}
{"time":"2026-11-10T11:45:54.304Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","zoomFactor":1.25}}
{"time":"2026-11-10T11:45:54.612Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:54.613Z","event":"gate.release","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","mode":"resolve"}
{"time":"2026-11-10T11:45:56.117Z","tool":"preview_status","caller":0,"args":{"tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}}
{"time":"2026-11-10T11:45:56.117Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:56.132Z","tool":"t3_preview_close","caller":0,"args":{"tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}}
{"time":"2026-11-10T11:45:56.149Z","event":"RPC.send","method":"preview.close","payload":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}}
```

Native fixture: Electron 44.10.1 / Chromium 152.0.7977.169; direct scratch desktop CDP binding, real WebContents native zoom.

After step times (UTC):

```jsonl
{"time":"2026-11-10T11:46:05.026Z","tool":"preview_open","caller":0,"args":{"reuseExistingTab":false,"open":false}}
{"time":"2026-11-10T11:46:09.110Z","event":"RPC.send","method":"preview.open","payload":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","url":"http://127.0.0.1:18766/desktop-fixture","runtime":"server","reveal":false}}
{"time":"2026-11-10T11:46:10.131Z","event":"native.state","route":"/zoom/1","result":{"width":1000,"height":673,"zoomFactor":1,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:10.132Z","tool":"preview_status","caller":0,"args":{"tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}}
{"time":"2026-11-10T11:46:10.154Z","tool":"preview_set_appearance","caller":0,"args":{"tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","colorScheme":"dark"}}
{"time":"2026-11-10T11:46:27.170Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","colorScheme":"light"}}
{"time":"2026-11-10T11:46:27.179Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","zoomFactor":1.25}}
{"time":"2026-11-10T11:46:27.186Z","event":"native.state","route":"/zoom/1.25","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:27.487Z","tool":"preview_evaluate","caller":0,"args":{"tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","expression":"({width:innerWidth,height:innerHeight})"}}
{"time":"2026-11-10T11:46:27.537Z","event":"RPC.send","method":"preview.adjust","payload":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","zoomFactor":1.25}}
{"time":"2026-11-10T11:46:27.849Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:27.850Z","event":"gate.release","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","mode":"resolve"}
{"time":"2026-11-10T11:46:29.354Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:29.355Z","tool":"preview_status","caller":0,"args":{"tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}}
{"time":"2026-11-10T11:46:29.374Z","tool":"t3_preview_close","caller":0,"args":{"tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}}
{"time":"2026-11-10T11:46:29.402Z","event":"RPC.send","method":"preview.close","payload":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}}
```

<a id="before-c24native"></a>
## Before — C24native

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

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

```jsonl
{"time":"2026-11-10T11:45:35.397Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","url":null,"loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:45:36.439Z","tool":"preview_status","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","url":"http://127.0.0.1:18766/desktop-fixture","loading":false,"control":{"owner":"unclaimed","ownedByCaller":false,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1000,"height":673},"tabs":[{"tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","owner":"agent","ownedByCaller":true},{"tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","owner":"unclaimed","ownedByCaller":false}]}}}
{"time":"2026-11-10T11:45:52.454Z","tool":"preview_set_appearance","caller":0,"result":{"content":[{"type":"text","text":"Preview automation setColorScheme timed out after 15000ms."}],"isError":true}}
{"time":"2026-11-10T11:45:54.304Z","tool":"preview_evaluate","caller":0,"result":{"isError":false,"structuredContent":{"toolIcon":{"_tag":"website","pageUrl":"http://127.0.0.1:18766/desktop-fixture"},"value":{"width":800,"height":538}}}}
{"time":"2026-11-10T11:45:56.132Z","tool":"preview_status","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","url":"http://127.0.0.1:18766/desktop-fixture","loading":false,"control":{"owner":"unclaimed","ownedByCaller":false,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":800,"height":538},"tabs":[{"tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","owner":"agent","ownedByCaller":true},{"tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","owner":"unclaimed","ownedByCaller":false}]}}}
{"time":"2026-11-10T11:45:56.149Z","tool":"t3_preview_close","caller":0,"result":{"isError":false,"structuredContent":{}}}
{"time":"2026-11-10T11:45:35.418Z","event":"RPC.result","method":"preview.open","result":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","navStatus":{"_tag":"Loading","url":"http://127.0.0.1:18766/desktop-fixture","title":""},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"runtime":"server","reveal":false,"updatedAt":"2026-11-10T11:45:35.407Z"}}
{"time":"2026-11-10T11:45:36.424Z","event":"native.state","route":"/zoom/1","result":{"width":1000,"height":673,"zoomFactor":1,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:53.966Z","event":"RPC.result","method":"preview.adjust","result":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","navStatus":{"_tag":"Idle"},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"colorScheme":"light","runtime":"server","automationOwner":"7bf116ee-dc7c-4dd9-9e80-001766fd7567\u0000de56af78-0e5c-4785-aa7e-57a41d5ca650\u00007118298a-7212-4878-9186-bd43c15dc3f2","reveal":false,"updatedAt":"2026-11-10T11:45:53.964Z"}}
{"time":"2026-11-10T11:45:53.971Z","event":"RPC.result","method":"preview.adjust","result":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","navStatus":{"_tag":"Success","url":"http://127.0.0.1:18766/desktop-fixture","title":"Synthetic browser fixture"},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"zoomFactor":1.25,"runtime":"server","reveal":false,"updatedAt":"2026-11-10T11:45:53.969Z"}}
{"time":"2026-11-10T11:45:53.976Z","event":"native.state","route":"/zoom/1.25","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:54.307Z","event":"RPC.result","method":"preview.adjust","result":{"threadId":"7118298a-7212-4878-9186-bd43c15dc3f2","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","navStatus":{"_tag":"Success","url":"http://127.0.0.1:18766/desktop-fixture","title":"Synthetic browser fixture"},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"zoomFactor":1.25,"runtime":"server","reveal":false,"updatedAt":"2026-11-10T11:45:54.305Z"}}
{"time":"2026-11-10T11:45:54.612Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:56.117Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:45:56.156Z","event":"RPC.result","method":"preview.close"}
```

Relevant server milestones:

```jsonl
{"time":"2026-11-10T11:45:21.834Z","event":"host.connected","connectionId":"e545f977-5c91-48ed-b2ab-c0e327785c17"}
{"time":"2026-11-10T11:45:33.653Z","event":"request.start","operation":"open","requestId":"preview-0","timeoutMs":660000,"connectionId":"e545f977-5c91-48ed-b2ab-c0e327785c17"}
{"time":"2026-11-10T11:45:35.382Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"tab.created","detail":{"desktop":false,"isolatedContext":true}}
{"time":"2026-11-10T11:45:35.383Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"setViewportSize.start","detail":[{"width":1280,"height":800}]}
{"time":"2026-11-10T11:45:35.384Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"setViewportSize.end","detail":{}}
{"time":"2026-11-10T11:45:35.385Z","event":"operation.settled","requestId":"preview-0","operation":"open","ok":true}
{"time":"2026-11-10T11:45:35.445Z","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"tab.created","detail":{"desktop":true,"isolatedContext":false}}
{"time":"2026-11-10T11:45:35.458Z","event":"mirror.received","type":"navigated","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}
{"time":"2026-11-10T11:45:36.422Z","event":"native.setZoomFactor","zoomFactor":1}
{"time":"2026-11-10T11:45:36.428Z","event":"request.start","operation":"status","requestId":"preview-1","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","timeoutMs":15000,"connectionId":"e545f977-5c91-48ed-b2ab-c0e327785c17"}
{"time":"2026-11-10T11:45:36.435Z","event":"operation.settled","requestId":"preview-1","operation":"status","ok":true}
{"time":"2026-11-10T11:45:36.447Z","event":"request.start","operation":"setColorScheme","requestId":"preview-2","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","timeoutMs":15000,"connectionId":"e545f977-5c91-48ed-b2ab-c0e327785c17"}
{"time":"2026-11-10T11:45:36.448Z","event":"mirror.received","type":"resized","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}
{"time":"2026-11-10T11:45:36.448Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"emulateMedia.start","detail":[{"colorScheme":"dark"}]}
{"time":"2026-11-10T11:45:36.448Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"emulateMedia.held","detail":{}}
{"time":"2026-11-10T11:45:53.449Z","event":"host.connected","connectionId":"ad80c0f6-98cf-4606-9c52-42db44a86a7b"}
{"time":"2026-11-10T11:45:53.974Z","event":"native.setZoomFactor","zoomFactor":1.25}
{"time":"2026-11-10T11:45:54.290Z","event":"request.start","operation":"evaluate","requestId":"preview-3","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","timeoutMs":15000,"connectionId":"ad80c0f6-98cf-4606-9c52-42db44a86a7b"}
{"time":"2026-11-10T11:45:54.294Z","event":"operation.settled","requestId":"preview-3","operation":"evaluate","ok":true}
{"time":"2026-11-10T11:45:54.630Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"emulateMedia.end","detail":{}}
{"time":"2026-11-10T11:45:54.630Z","event":"operation.settled","requestId":"preview-2","operation":"setColorScheme","ok":true}
{"time":"2026-11-10T11:45:54.631Z","event":"mirror.received","type":"resized","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}
{"time":"2026-11-10T11:45:54.631Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"emulateMedia.start","detail":[{"colorScheme":"light"}]}
{"time":"2026-11-10T11:45:54.633Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"emulateMedia.end","detail":{}}
{"time":"2026-11-10T11:45:54.633Z","event":"mirror.received","type":"resized","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}
{"time":"2026-11-10T11:45:54.633Z","event":"mirror.received","type":"resized","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e"}
{"time":"2026-11-10T11:45:56.121Z","event":"request.start","operation":"status","requestId":"preview-5","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","timeoutMs":15000,"connectionId":"ad80c0f6-98cf-4606-9c52-42db44a86a7b"}
{"time":"2026-11-10T11:45:56.127Z","event":"operation.settled","requestId":"preview-5","operation":"status","ok":true}
{"time":"2026-11-10T11:45:56.144Z","event":"request.start","operation":"close","requestId":"preview-6","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","timeoutMs":15000,"connectionId":"ad80c0f6-98cf-4606-9c52-42db44a86a7b"}
{"time":"2026-11-10T11:45:56.144Z","event":"dropTab","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","recording":false}
{"time":"2026-11-10T11:45:56.144Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"close.start","detail":[]}
{"time":"2026-11-10T11:45:56.144Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"context.close.start","detail":{}}
{"time":"2026-11-10T11:45:56.145Z","event":"dropTab","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","recording":false}
{"time":"2026-11-10T11:45:56.145Z","event":"operation.settled","requestId":"preview-6","operation":"close","ok":true}
{"time":"2026-11-10T11:45:56.150Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"page.closed","detail":{}}
{"time":"2026-11-10T11:45:56.150Z","event":"dropTab","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","recording":false}
{"time":"2026-11-10T11:45:56.150Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"close.end","detail":{}}
{"time":"2026-11-10T11:45:56.151Z","tabId":"tab_1_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","event":"context.close.end","detail":{}}
{"time":"2026-11-10T11:45:56.152Z","event":"dropTab","tabId":"tab_2_76e54a2e-e007-47fa-b3b0-5fa820d7ad2e","recording":false}
```

<a id="after-c24native"></a>
## After — C24native

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

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

```jsonl
{"time":"2026-11-10T11:46:09.109Z","tool":"preview_open","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","url":null,"loading":false,"control":{"owner":"agent","ownedByCaller":true,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1280,"height":800},"tabs":[{"tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","owner":"agent","ownedByCaller":true}]}}}
{"time":"2026-11-10T11:46:10.153Z","tool":"preview_status","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","url":"http://127.0.0.1:18766/desktop-fixture","loading":false,"control":{"owner":"unclaimed","ownedByCaller":false,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":1000,"height":673},"tabs":[{"tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","owner":"agent","ownedByCaller":true},{"tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","owner":"unclaimed","ownedByCaller":false}]}}}
{"time":"2026-11-10T11:46:25.668Z","tool":"preview_set_appearance","caller":0,"result":{"content":[{"type":"text","text":"Preview automation setColorScheme timed out after 15000ms."}],"isError":true}}
{"time":"2026-11-10T11:46:27.537Z","tool":"preview_evaluate","caller":0,"result":{"isError":false,"structuredContent":{"toolIcon":{"_tag":"website","pageUrl":"http://127.0.0.1:18766/desktop-fixture"},"value":{"width":800,"height":538}}}}
{"time":"2026-11-10T11:46:29.372Z","tool":"preview_status","caller":0,"result":{"isError":false,"selectedStatusFields":{"available":true,"tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","url":"http://127.0.0.1:18766/desktop-fixture","loading":false,"control":{"owner":"unclaimed","ownedByCaller":false,"generation":0},"dialog":null,"viewportSetting":{"_tag":"fill"},"viewport":{"width":800,"height":538},"tabs":[{"tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","owner":"agent","ownedByCaller":true},{"tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","owner":"unclaimed","ownedByCaller":false}]}}}
{"time":"2026-11-10T11:46:29.402Z","tool":"t3_preview_close","caller":0,"result":{"isError":false,"structuredContent":{}}}
{"time":"2026-11-10T11:46:09.124Z","event":"RPC.result","method":"preview.open","result":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","navStatus":{"_tag":"Loading","url":"http://127.0.0.1:18766/desktop-fixture","title":""},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"runtime":"server","reveal":false,"updatedAt":"2026-11-10T11:46:09.115Z"}}
{"time":"2026-11-10T11:46:10.131Z","event":"native.state","route":"/zoom/1","result":{"width":1000,"height":673,"zoomFactor":1,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:27.179Z","event":"RPC.result","method":"preview.adjust","result":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","navStatus":{"_tag":"Idle"},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"colorScheme":"light","runtime":"server","automationOwner":"4104ffcb-a5c7-4d3c-b1b7-473064e237db\u00004d64a919-6148-4c35-bd5f-9ec2ef89606d\u00006f4c5fc8-1fa9-4720-8984-7aa49b58d63f","reveal":false,"updatedAt":"2026-11-10T11:46:27.176Z"}}
{"time":"2026-11-10T11:46:27.182Z","event":"RPC.result","method":"preview.adjust","result":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","navStatus":{"_tag":"Success","url":"http://127.0.0.1:18766/desktop-fixture","title":"Synthetic browser fixture"},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"zoomFactor":1.25,"runtime":"server","reveal":false,"updatedAt":"2026-11-10T11:46:27.180Z"}}
{"time":"2026-11-10T11:46:27.186Z","event":"native.state","route":"/zoom/1.25","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:27.543Z","event":"RPC.result","method":"preview.adjust","result":{"threadId":"6f4c5fc8-1fa9-4720-8984-7aa49b58d63f","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","navStatus":{"_tag":"Success","url":"http://127.0.0.1:18766/desktop-fixture","title":"Synthetic browser fixture"},"canGoBack":false,"canGoForward":false,"viewport":{"_tag":"fill"},"zoomFactor":1.25,"runtime":"server","reveal":false,"updatedAt":"2026-11-10T11:46:27.541Z"}}
{"time":"2026-11-10T11:46:27.849Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:29.354Z","event":"native.state","route":"/state","result":{"width":800,"height":538,"zoomFactor":1.25,"electron":"44.10.1","chrome":"152.0.7977.169"}}
{"time":"2026-11-10T11:46:29.412Z","event":"RPC.result","method":"preview.close"}
```

Relevant server milestones:

```jsonl
{"time":"2026-11-10T11:45:22.108Z","event":"host.connected","connectionId":"84bd5528-0f01-48c8-8f99-3760e0207dd2"}
{"time":"2026-11-10T11:46:05.038Z","event":"request.start","operation":"open","requestId":"preview-0","timeoutMs":660000,"connectionId":"84bd5528-0f01-48c8-8f99-3760e0207dd2"}
{"time":"2026-11-10T11:46:09.094Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"tab.created","detail":{"desktop":false,"isolatedContext":true}}
{"time":"2026-11-10T11:46:09.095Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"setViewportSize.start","detail":[{"width":1280,"height":800}]}
{"time":"2026-11-10T11:46:09.096Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"setViewportSize.end","detail":{}}
{"time":"2026-11-10T11:46:09.098Z","event":"operation.settled","requestId":"preview-0","operation":"open","ok":true}
{"time":"2026-11-10T11:46:09.139Z","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"tab.created","detail":{"desktop":true,"isolatedContext":false}}
{"time":"2026-11-10T11:46:09.145Z","event":"mirror.received","type":"navigated","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}
{"time":"2026-11-10T11:46:10.128Z","event":"native.setZoomFactor","zoomFactor":1}
{"time":"2026-11-10T11:46:10.139Z","event":"request.start","operation":"status","requestId":"preview-1","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","timeoutMs":15000,"connectionId":"84bd5528-0f01-48c8-8f99-3760e0207dd2"}
{"time":"2026-11-10T11:46:10.148Z","event":"operation.settled","requestId":"preview-1","operation":"status","ok":true}
{"time":"2026-11-10T11:46:10.162Z","event":"request.start","operation":"setColorScheme","requestId":"preview-2","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","timeoutMs":15000,"connectionId":"84bd5528-0f01-48c8-8f99-3760e0207dd2"}
{"time":"2026-11-10T11:46:10.163Z","event":"mirror.received","type":"resized","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}
{"time":"2026-11-10T11:46:10.164Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"emulateMedia.start","detail":[{"colorScheme":"dark"}]}
{"time":"2026-11-10T11:46:10.164Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"emulateMedia.held","detail":{}}
{"time":"2026-11-10T11:46:27.176Z","event":"mirror.received","type":"resized","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}
{"time":"2026-11-10T11:46:27.180Z","event":"mirror.received","type":"resized","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}
{"time":"2026-11-10T11:46:27.184Z","event":"native.setZoomFactor","zoomFactor":1.25}
{"time":"2026-11-10T11:46:27.505Z","event":"request.start","operation":"evaluate","requestId":"preview-3","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","timeoutMs":15000,"connectionId":"84bd5528-0f01-48c8-8f99-3760e0207dd2"}
{"time":"2026-11-10T11:46:27.510Z","event":"operation.settled","requestId":"preview-3","operation":"evaluate","ok":true}
{"time":"2026-11-10T11:46:27.541Z","event":"mirror.received","type":"resized","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6"}
{"time":"2026-11-10T11:46:27.855Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"emulateMedia.end","detail":{}}
{"time":"2026-11-10T11:46:27.855Z","event":"operation.settled","requestId":"preview-2","operation":"setColorScheme","ok":true}
{"time":"2026-11-10T11:46:27.855Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"emulateMedia.start","detail":[{"colorScheme":"light"}]}
{"time":"2026-11-10T11:46:27.857Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"emulateMedia.end","detail":{}}
{"time":"2026-11-10T11:46:29.359Z","event":"request.start","operation":"status","requestId":"preview-5","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","timeoutMs":15000,"connectionId":"84bd5528-0f01-48c8-8f99-3760e0207dd2"}
{"time":"2026-11-10T11:46:29.365Z","event":"operation.settled","requestId":"preview-5","operation":"status","ok":true}
{"time":"2026-11-10T11:46:29.387Z","event":"request.start","operation":"close","requestId":"preview-6","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","timeoutMs":15000,"connectionId":"84bd5528-0f01-48c8-8f99-3760e0207dd2"}
{"time":"2026-11-10T11:46:29.389Z","event":"dropTab","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","recording":false}
{"time":"2026-11-10T11:46:29.390Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"close.start","detail":[]}
{"time":"2026-11-10T11:46:29.391Z","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"context.close.start","detail":{}}
{"time":"2026-11-10T11:46:29.393Z","event":"dropTab","tabId":"tab_1_c5426f08-2c58-42e7-93d9-6558d7fb22f6","recording":false}
{"time":"2026-11-10T11:46:29.395Z","event":"operation.settled","requestId":"preview-6","operation":"close","ok":true}
{"time":"2026-11-10T11:46:29.406Z","event":"dropTab","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","recording":false}
{"time":"2026-11-10T11:46:29.411Z","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","event":"page.closed","detail":{}}
{"time":"2026-11-10T11:46:29.412Z","event":"dropTab","tabId":"tab_2_c5426f08-2c58-42e7-93d9-6558d7fb22f6","recording":false}
```

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