Show a link to debug.log in the agentic UI when the file exists

[wojtekn]

Related issues

• Fixes STU-2404

How AI was used in this PR

Claude Code wrote the implementation and tests, and drove the browser verification below. I reviewed the diff, directed the button styling and other improvements.

Proposed Changes

Studio Classic offers an Open log file link in site Settings once a site has actually written a wp-content/debug.log. The agentic UI had the Enable debug log toggle but no way to get to the file it produces, so you had to go find it in the site folder yourself. This ports that shortcut, as a button under the toggle, matching the mockup on the issue.

Testing Instructions

Browser UI:

npm run cli:build:ui && node apps/cli/dist/cli/main.mjs ui --no-open

Then at http://localhost:8081 → a site → Settings → Debugging. Repeat the same steps on the desktop app (npm start) — both front ends are in scope.

1. On a site with no wp-content/debug.log, there's no button.
2. On a site that has one, Open log file appears below the toggle's description; the description itself is still there.
3. Click it — the log opens in the OS default app (TextEdit/Notepad), not your configured editor.
4. rm wp-content/debug.log, then navigate to another site and back — the button is gone. Restore the file and it returns.
5. Check both light and dark mode.

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[wpmobilebot]

📊 Performance Test Results

Comparing 40d892e vs trunk

app-size

Metric	trunk	40d892e	Diff	Change
App Size (Mac)	1425.96 MB	1425.96 MB	0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	40d892e	Diff	Change
load	1188 ms	1305 ms	+117 ms	🔴 9.8%

site-startup

Metric	trunk	40d892e	Diff	Change
siteCreation	7517 ms	7548 ms	+31 ms	⚪ 0.0%
siteStartup	3371 ms	3369 ms	2 ms	⚪ 0.0%

---

Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)

[youknowriad]

Tested in the browser UI, works as described, and the code is clean: both connectors covered, good wire-contract tests. 👍

One edge case worth a look: when the user unchecks the toggle and saves, the query is disabled but React Query keeps the cached true, so the Open log file button stays visible until a reload.

Minor nits, take or leave:

• Classic still hardcodes 'wp-content/debug.log' in content-tab-settings.tsx — could use the new DEBUG_LOG_RELATIVE_PATH since that's what it's for.
• Other "open" actions fire a Tracks event; this one doesn't. Fine to skip if we don't need the data.

---

A few things maybe worth cutting/removing from the PR to keep things lean:

• The enabled param on useDebugLogExists, removing this also fixes the stale-button bug above. Always run the check when openInOS is true.
• The 4 IPC connector tests feels unnecessary to. me.
• Hosted connector's siteDebugLogExists could throw UnsupportedError like the other similar functions.
• One of the two "404s for an unknown site" route tests (they check the same thing).

[wojtekn]

@youknowriad thanks for review.

I fixed the query so it depends only on whether the file exists - this also means the button now shows for sites that have a debug.log but logging turned off, what is consistent with classic UI.

I also applied a few proposed cleanup and quality things.