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gem-skill logo Generate SKILL.md files for AI coding assistants (Claude Code, OpenAI Codex, and others) from Ruby gem documentation, and cache them globally so every project that uses a gem can share the same pre-built knowledge.

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The problem it solves

Every time an AI coding assistant encounters a gem it hasn't seen in the current context, it re-reads the README, scans examples, and figures out the API. That costs tokens and time — and the result evaporates when the conversation ends.

gem-skill runs that pipeline once, offline, and stores the output as a SKILL.md in ~/.gem/skills. Projects symlink to the cached version, so your assistant has accurate, version-specific knowledge about each gem without repeating the ingestion work. SKILL.md is a shared format — Claude Code, OpenAI Codex, and other assistants all read it.

Quick start

# 1. Install
gem install gem-skill

# 2. Register the Bundler plugin (once per machine)
gem skill setup

# 3. Generate a skill for any installed gem
gem skill install debug_me

# 4. In a project — generate skills for all direct dependencies
cd your-project
bundle skill install

How it works

gem README / changelog / RubyGems API
        ↓
   Fetcher collects docs
        ↓
   Generator calls LLM (ruby_llm)
        ↓
   SKILL.md cached at ~/.gem/skills/<gem>/<version>/
        ↓
   Linker creates .claude/skills/<gem> → cache dir
        ↓
   The assistant reads SKILL.md automatically
   (Claude Code from .claude/skills/; other assistants from their own roots)

All concurrent work is handled by async fibers — multiple gems are processed simultaneously with live TTY spinner progress.

Key features

  • Global cache — generate once, use everywhere; skills are version-specific
  • Gemfile.lock awareness — bundle skill install installs skills for every direct dependency including gemspec runtime deps
  • Concurrent — all LLM calls run concurrently via async fibers
  • Two interfaces — gem skill for global cache management, bundle skill for project-aware linking
  • Auto-install — gem install --with-skill generates skills during normal gem installation
  • Configurable — GEMSKILL_DIR, GEMSKILL_PROJECT_DIR, and GEMSKILL_MODEL environment variables
  • Multi-assistant — SKILL.md works with Claude Code, OpenAI Codex, and others; GEMSKILL_PROJECT_DIR points project links at the right directory