Start here before building anything from scratch.
**anthropics/skills** β Anthropic's own reference implementations. Read these before writing your own skills; they set the standard for structure, safety, and progressive disclosure.
**claude-code-action** β the headless/CI pattern for running Claude in automated pipelines.
**Official Plugin Directory** β the canonical list of what's been built and sanctioned.
**Engineering posts worth reading closely:** 'How Claude Code Works' (architecture), 'How We Built Our Multi-Agent Research System' (canonical orchestrator/subagent design β this is the reference for Sprint 6), 'Steering Claude Code' (the extension decision framework: when to use hooks vs skills vs subagents), and 'Skills Explained' (progressive disclosure + decision matrices).
**docs.claude.com** β the live reference for Agent SDK, Skills API, MCP docs, and the prompt engineering guide. Check it before trusting anything older than three months.