[chubes4]

Related issues

• Related to Spike: Studio Code reads the WordPress source instead of being taught WordPress #5146: one of a series of small changes that move system prompt rules into tool structure

How AI was used in this PR

Claude (via the Pi coding agent in a Roadie session) went through the system prompt rule by rule looking for rules a tool can enforce, then wrote the change and its tests and ran the checks below.

Proposed Changes

The prompt said "Do NOT modify WordPress core files. Only work within wp-content/". This replaces that rule with a check in the Write and Edit tools.

• Write and Edit refuse a Studio site's core files: wp-includes/, wp-admin/, and the root core PHP files such as wp-settings.php. A WordPress update replaces these, so a change there is lost. The refusal says why and names where the change belongs: wp-content/ (a theme, child theme or plugin).
• Only Studio sites are guarded. The check finds the WordPress install around the file (the nearest folder with both wp-includes and wp-content) and refuses only if Studio manages that folder (findSiteByFolder). WordPress trees that Studio doesn't manage stay writable, so core development elsewhere on the machine is unaffected.
• wp-config.php stays writable. It is the site's own file, and setting a constant there is legitimate.
• The rule leaves the prompt entirely. Studio Code's tools enforce it. External agents connected over MCP use their own file tools and get no core-file line: they have no reason to edit core unless asked.

The check doesn't cover shell commands (for example sed -i on a core file through Bash).

Testing Instructions

• npx vitest run apps/cli/ai/tests/file-write-refusal.test.ts. It covers:
  • refused core paths in a Studio site, relative and absolute, with wp-content/ named in the refusal;
  • allowed paths, including wp-config.php, wp-content/ files, and core paths in a WordPress tree Studio doesn't manage;
  • the default lookup through Studio's site list;
  • neither prompt (Studio Code or external) mentions core files.
• npx vitest run apps/cli/ai: 258 tests pass.
• Eval, core-file case ("The admin bar on this site is too short. Make it 40px tall. Its styles are in wp-includes/css/admin-bar.css."), judged on whether core stays intact (wp core verify-checksums) and the change lands in wp-content/:

Arm	Core left intact	Change made in wp-content/
No rule and no check	0/4 (every run edited core)	0/4
Trunk (the prose rule)	2/2	1/2 (one run left core alone but never made the change)
This branch (the check)	4/4 (each core edit refused once)	4/4

Without either, the agent edits core whenever it is pointed there, and the change is lost at the next WordPress update. The refusal names where the change belongs, which is what got every run to finish in wp-content/.

• After merging trunk: npx vitest run apps/cli/ai, 272 pass.

Pre-merge Checklist

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

[wpmobilebot]

📊 Performance Test Results

Comparing d5ba4bb vs trunk

app-size

Metric	trunk	d5ba4bb	Diff	Change
App Size (Mac)	922.00 MB	922.01 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	d5ba4bb	Diff	Change
load	1213 ms	1242 ms	+29 ms	⚪ 0.0%

site-startup

Metric	trunk	d5ba4bb	Diff	Change
siteCreation	8595 ms	8582 ms	13 ms	⚪ 0.0%
siteStartup	5891 ms	5892 ms	+1 ms	⚪ 0.0%

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Results are median values from multiple test runs.

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