CLAUDE.md — Always-loaded project memory

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NOTE

CLAUDE.md is the file Claude Code reads at the start of every session. It defines project-wide context that should always be available: conventions, terminology, build commands, and behavioral expectations.

How it works

• Loaded into context once per session, before the first user message.
• Hierarchical: project-level, user-level (~/.claude/CLAUDE.md), and CLAUDE.local.md merge in a defined order.
• Every token here is paid on every turn — keep it terse.

Related chapters

• Part 3 — Always-Loaded Context (overview)
• CLAUDE.md Design
• Hierarchical Merging
• CLAUDE.local.md
• Configuration Reference

Structural problems it addresses

• Context Rot — keep CLAUDE.md small to slow accuracy decay.
• Instruction Decay — re-grounding through always-loaded content.
• Priority Saturation — too much in CLAUDE.md blurs what matters.

See also

• Topic: Rules — for context that should load only sometimes.
• Topic: Skills & Agents — for context that should load on demand.
• Feature Index — cross-feature cheatsheet.