[Bug]: preview_resize times out and leaves viewport state internally inconsistent

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Steps to reproduce

1. Start T3 Code Desktop.

2. Open a Codex-backed thread with the T3 preview MCP tools available.

3. Serve any local web page and open it in the preview:

   python -m http.server 8000 --directory build/site
   

   {
     "show": true,
     "reuseExistingTab": false,
     "url": "http://localhost:8000/index.html"
   }
   

4. Call preview_resize in freeform mode:

   {
     "mode": "freeform",
     "width": 1920,
     "height": 1200,
     "timeoutMs": 15000
   }
   

5. Check both preview_status and the live DOM viewport:

   ({ innerWidth, innerHeight, devicePixelRatio })
   

6. Repeat with mode: "fill" and with the iphone-12-pro preset.

7. Call preview_snapshot after the resize attempts.

Expected behavior

preview_resize should either:

• complete successfully and make viewportSetting, measured viewport, live DOM innerWidth/innerHeight, and snapshot screenshot size agree, or
• fail without partially changing tab state.

If exact sizing is impossible, the tool should return the effective viewport and explain the mismatch.

Actual behavior

Each resize call timed out after 15 seconds but still partially changed state.

After freeform 1920x1200, preview_status reported the requested setting while the measured viewport and live DOM viewport stayed at 1280x800:

{
  "viewportSetting": { "_tag": "freeform", "width": 1920, "height": 1200 },
  "viewport": { "width": 1280, "height": 800 }
}

{
  "innerWidth": 1280,
  "innerHeight": 800,
  "devicePixelRatio": 2.190890312194824
}

Later, the same requested setting drifted to a measured viewport of 2103x1314.

After a timed-out fill resize, measured and live viewport changed to about 410x987.

After a timed-out iphone-12-pro preset resize, viewportSetting changed to 390x844, but measured and live viewport were about 427x924:

{
  "viewportSetting": {
    "_tag": "preset",
    "width": 390,
    "height": 844,
    "presetId": "iphone-12-pro"
  },
  "viewport": { "width": 427, "height": 924 }
}

preview_snapshot also returned a PNG screenshot sized 1280x800 while preview_status reported a measured viewport of 2103x1314.

Impact

Major degradation or frequent failure

Version or commit

T3 Code desktop 0.0.28-1 via t3code-bin AUR package.

Environment

Arch Linux x86_64, kernel 7.0.13-arch1-1, T3 Code desktop AppImage package via t3code-bin, Codex provider.

Logs or stack traces

Representative resize failure:


PreviewAutomationTimeoutError: Preview automation resize timed out after 15000ms.


The important diagnostic is that status/live viewport values diverge after the timeout, as shown above.

Screenshots, recordings, or supporting files

No response

Workaround

After any resize timeout, treat viewport state as unknown. Measure the effective viewport with preview_evaluate using innerWidth and innerHeight, and compute interaction coordinates from live DOM geometry instead of snapshot coordinates.

Start with the preview_resize, preview_status, and preview_snapshot entry points and reproduce the freeform, fill, and iphone-12-pro timeout cases. Trace the timeout path and compare the requested setting, measured viewport, live DOM dimensions, and screenshot size. Done means successful resizes keep these values consistent, while failures leave tab state unchanged or report the effective viewport.