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codestyle-harness

Claude Code plugin. Makes Claude write new code in your framework conventions, not its default style. Conventions live in a curated catalog of codestyle idioms.

Repo = marketplace + single plugin at root. Installs like any skills plugin.

How it works

One idiom = folder codestyles/<framework>/<name>/, three files:

File	Holds
STYLE.md	intent, numbered rules, use-when / use-when-not
example.<ext>	canonical reference to imitate
checklist.md	yes/no conformance points

codestyles/<framework>/INDEX.md = catalog the harness reads to pick idioms.

Two skills:

• apply-codestyle — consume, in other projects. Decompose task → retrieve matching idioms → implement → verify vs checklist → record enforcement. Reads ${CLAUDE_PLUGIN_ROOT}/codestyles/.
• add-codestyle — develop, in this repo. Discuss → author idiom (STYLE.md + example + checklist) → update INDEX. Writes ./codestyles/.

Split is deliberate: consume from installed plugin, grow here, push, consumers update.

Enforcement note

Retrieval alone is amnesiac — next session, plain prompt, skill never fires, default style returns. So apply-codestyle registers what it applied in the consuming project:

project/
├── CLAUDE.md              # gains one line: @.claude/codestyle.md
└── .claude/codestyle.md   # idioms in force → name, scope, where to read

Pointer only. No rules copied — a copy goes stale the moment the catalog moves. The note says which idioms bind and to read them from the plugin; the catalog stays the single source of truth. Merged on re-run, never clobbered.

The loop closes at step 0: apply-codestyle reads the note first, so idioms already in force are binding for the next task too.

Install (consumers)

/plugin marketplace add QuantMis/codestyle-harness
/plugin install codestyle-harness@codestyle-harness

Then ask Claude to build a feature — apply-codestyle fires, follows the catalog. Get new idioms later: /plugin update.

Add an idiom (maintainer)

In this repo: run add-codestyle, or copy an idiom folder. Keep single-purpose, every rule checkable, example passes its own checklist. Commit + push.

Layout

codestyle-harness/
├── .claude-plugin/
│   ├── plugin.json          # plugin manifest (skills auto-discovered from ./skills)
│   └── marketplace.json     # marketplace catalog (this plugin, source "./")
├── skills/
│   ├── apply-codestyle/SKILL.md
│   └── add-codestyle/SKILL.md
└── codestyles/
    └── laravel/
        ├── INDEX.md         # the catalog for Laravel idioms
        └── crud-controller/
            ├── STYLE.md
            ├── example.php
            └── checklist.md

Notes

• Namespaced by framework — no cross-stack bleed, cheap retrieval.
• No version in plugin.json → auto-versions by git SHA, no manual bumps. Add semver later for explicit releases.
• Skills model-invocable by default. Explicit-only: add disable-model-invocation: true to frontmatter.