Anvil

Scaffold, validate, and test Claude Code plugins

claude plugin marketplace add heurema/emporium   # once
claude plugin install anvil@emporium

What it does

Anvil is the official plugin development toolkit for the heurema ecosystem. It covers the complete plugin lifecycle: scaffold a new plugin from heurema-standard templates, run six sequential validators to catch schema errors, missing files, and unsafe hook scripts before you publish, and execute fixture-driven hook tests to verify runtime behaviour. A built-in code-review agent applies a 21-item quality checklist and returns an explicit APPROVE or REQUEST CHANGES verdict. Everything runs locally — no network, no credentials.

Install

claude plugin marketplace add heurema/emporium
claude plugin install anvil@emporium

Manual install (from source)

git clone https://github.com/heurema/anvil.git ~/.claude/plugins/anvil

Then add to ~/.claude/settings.json:

{
  "permissions": {
    "allow": ["Bash(~/.claude/plugins/anvil/hooks/*)"]
  }
}

Open a new Claude Code session to activate.

Quick start

/anvil:new my-plugin
/anvil:check ./my-plugin
/anvil:test  ./my-plugin

Commands

Command	What it does
/anvil:new	Scaffold a complete plugin skeleton from heurema-standard templates
/anvil:check	Run six sequential validators and return a single PASS/FAIL verdict
/anvil:test	Execute fixture-driven hook tests to verify runtime behaviour

Features

• Scaffolding — /anvil:new generates a conventions-compliant plugin skeleton (plugin.json, README, LICENSE, CHANGELOG, .gitignore); optionally initialises a git repo and creates a GitHub repository under the heurema org.
• Six-layer validation — /anvil:check runs schema, structure, hooks, conventions, consistency, and install-docs validators in sequence and aggregates results into a JSON report.
• Fixture-driven hook testing — /anvil:test executes scripts/test_hooks.py against your hook scripts and checks skill descriptions for presence, voice, length, and keywords.
• AI code review — The anvil-reviewer agent (sonnet, read-only) applies a 21-item checklist and gives an unambiguous APPROVE or REQUEST CHANGES verdict.
• Zero network dependency — all validation and scaffolding is local; the optional gh repo create step is explicit and opt-in.

Requirements

• Claude Code with plugin support
• Python 3.14+ (for validator scripts and test framework)
• jq (for hook validators)
• gh CLI — optional, only needed if you want /anvil:new to create a GitHub repository

Privacy

Anvil makes no network calls during validation or scaffolding. No plugin files, metadata, or diagnostic output leave your machine. The optional GitHub repository creation step in /anvil:new uses your local gh CLI and is gated behind an explicit confirmation prompt.

See also

• skill7.dev — plugin catalog and docs
• emporium — the heurema marketplace
• forge — plugin publishing and release pipeline
• signum — risk-adaptive development pipeline with adversarial consensus code review

License

MIT