If a team wants its Claude Code agents to remember decisions and context, three tools come up: a CLAUDE.md file, Git itself, and an MCP memory server. They're often framed as competitors. They're not — they cover different layers. Here's the boundary.
CLAUDE.md: standing instructions, per repo
CLAUDE.md is a file Claude Code reads automatically. It's the right home for stable, repo-scoped conventions: coding style, architecture notes, "run the tests with this command," "money is integer cents."
Good at: durable rules that rarely change; zero setup; versioned with the code.
Where it stops: it's static and per-repo. It's a poor fit for "what did we decide this morning," which changes daily, and it doesn't cross repos or capture a decision at the moment an agent makes one. It also doesn't help two agents avoid editing the same file right now.
