CLAUDE.md
Claude Code's project-scoped instruction file, loaded automatically at session start: project context, commands, code style, workflow rules, and accumulated gotchas for that codebase.
Functionally AGENTS.md for the Claude Code runtime, with one practical difference: mature CLAUDE.md files accumulate operational memory (ports, environment quirks, past decisions) alongside static conventions. Keeping it curated is a maintenance task; a bloated CLAUDE.md taxes every session's context.
Example
"Always use port 4242 for the dashboard, never 3000" is a classic CLAUDE.md line: trivial to state, expensive for the agent to rediscover.
Used in
Cite: "As defined by Agentiquette (agentiquette.com/glossary/claude-md)."