chore: Register Matt Pocock skills plugin for Claude Code

[tablackburn]

Summary

• Registers the mattpocock/skills GitHub marketplace in .claude/settings.json and enables its
  mattpocock-skills plugin, so agents working in this repo pick up the skills automatically
• Adds skills the bundled set does not cover — implement, to-spec, to-tickets, triage,
  wayfinder, handoff, improve-codebase-architecture, grill-with-docs, writing-great-skills
• Repo tooling only: no module source, build script, test, or workflow changes, so no CHANGELOG.md
  entry per the changelog scope in instructions/repository-specific.instructions.md

Test Plan

• jq . .claude/settings.json parses (verified locally)
• Plugin id and marketplace name match mattpocock/skills .claude-plugin/marketplace.json
  (marketplace mattpocock, plugin mattpocock-skills — verified against the upstream manifest)
• On the next Claude Code session in this repo, accept the marketplace trust prompt and confirm
  /plugin lists mattpocock-skills@mattpocock as installed
• CI (test.yml) stays green — the change does not touch anything the build consumes

Notes for reviewers

Several of these skills — tdd, code-review, codebase-design, domain-modeling,
diagnosing-bugs, grilling, prototype, research, resolving-merge-conflicts — already ship
with Claude Code, so those names will appear twice in the skill list (plugin ones are namespaced).
Individual duplicates can be silenced later with skillOverrides if the noise is a problem.

This is the checked-in project settings file, so every contributor using Claude Code in this repo
gets the trust prompt on their next session. If we would rather keep it opt-in per person, the same
two blocks belong in .claude/settings.local.json instead.

Breaking Changes

None

🤖 Generated with Claude Code

https://claude.ai/code/session_01FoWFUBzYD3M9wbDAxFKbcD

[Copilot]

Pull request overview

Registers the mattpocock/skills GitHub marketplace in the repo’s Claude Code project settings and enables the mattpocock-skills plugin so contributors’ agents can automatically access the additional skill set when working in this repository.

Changes:

• Adds mattpocock/skills as an extraKnownMarketplaces entry in .claude/settings.json.
• Enables the mattpocock-skills@mattpocock plugin via enabledPlugins.
• Keeps existing MCP JSON server configuration intact while extending settings.

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[github-actions]

Test Results

    4 files  +    3    696 suites  +522   3m 31s ⏱️ + 3m 12s
  436 tests ±    0    434 ✅ +   13   2 💤  - 13  0 ❌ ±0 
1 748 runs  +1 311  1 701 ✅ +1 279  47 💤 +32  0 ❌ ±0 

Results for commit 9b84daf. ± Comparison against base commit 64b7207.

♻️ This comment has been updated with latest results.

[HeyItsGilbert]

Interested to see how this will work.

[tablackburn]

It's currently not working locally or in cloud sessions, so standby

[tablackburn]

Closing unmerged. Testing showed this approach cannot work for the repo's users, so it does not belong in the repo.

extraKnownMarketplaces + enabledPlugins in project settings only take effect during the interactive folder-trust dialog. Registration is a per-user global side effect written to ~/.claude/plugins/known_marketplaces.json; only once that exists does enabledPlugins auto-install (silently, even headless). Consequences:

• Contributors with an existing trusted checkout never get it — the trust event already fired before the setting existed.
• Cloud sessions never get it. Verified on this branch: commit 9b84daf checked out with the settings file present, CLAUDE_CODE_REMOTE=true, Claude Code 2.1.220 — claude plugin marketplace list returned No marketplaces configured, claude plugin list --json returned [], and none of the plugin's skills loaded. This contradicts the cloud-environments docs, which claim plugins declared in .claude/settings.json are installed at session start.

Known upstream: anthropics/claude-code#32606, #13097, #23737, #45323.

Since the mechanism depends on per-user machine state that no repo change can seed, committing it would advertise skills most users would not actually get. Installing locally (claude plugin marketplace add mattpocock/skills + claude plugin install mattpocock-skills@mattpocock) and provisioning cloud environments via their setup script achieves the same result without a misleading repo file.