Build Up Claude's Memory Over Time with CLAUDE.md

Claude Code's memory lives in plain text files — your global ~/.claude/CLAUDE.md and each project's .claude/CLAUDE.md. When you want Claude to remember something permanently, you write it there.

The fastest way to add a memory mid-session is the # prefix:

# remember that I prefer Pest over PHPUnit for all tests
# remember that we use conventional commits in this project
# always run tests before marking any task as complete

Each line is added to your user-level memory file immediately.

For project-specific preferences, ask Claude to write directly to CLAUDE.md:

Add a rule to CLAUDE.md: always use the service layer for business logic — 
controllers should only handle HTTP.

Over time, your CLAUDE.md files accumulate exactly how you like to work — your test framework preferences, naming conventions, commit message format, when to ask vs when to proceed. Claude loads these at the start of every session, so you stop re-explaining the same things.

The global file is the right place for universal preferences:

## My Preferences
- I'm a senior developer — skip basic explanations
- Use conventional commits (feat:, fix:, chore:)
- Prefer composition over inheritance
- Always write tests for new functionality

Project-level CLAUDE.md is for project-specific rules that would be noise elsewhere.

The most valuable CLAUDE.md is the one that has grown through real corrections — every mistake you fix and capture makes every future session sharper.