CLAUDE.md
CLAUDE.md is a project memory and instructions file that Claude Code reads automatically to understand your conventions.
This week: 16% of 499 scanned repos had CLAUDE.md.See Radar #4 →
What it is
CLAUDE.md is a Markdown file at the project root (or in subfolders) that Claude Code loads as persistent context — describing architecture, commands, and rules for the assistant.
Why use it
It improves answer quality and lets you encode hygiene conventions, such as instructing the assistant to avoid reading or echoing secret files. It pairs well with .claudeignore for actual exclusion.
How to set it up
Create a CLAUDE.md in your project root and document setup commands, conventions, and any files the assistant should treat as off-limits.
# Project notes
## Hygiene
Do not read or print .env, *.key, or *.pem files.What to exclude
Common sensitive categories worth adding to CLAUDE.md:
FAQ
- Does CLAUDE.md block access to files?
- No. It provides instructions, not enforcement. Use .claudeignore to actually exclude sensitive files from context.
Check your own project
158 of 499 repos this week exposed sensitive paths to AI tools. Check yours in seconds:
Run the same local check with Offsend CLI:
brew install --cask offsend/tap/offsend-cli
offsend show
offsend prepare --dry-runEverything runs locally. No file contents are uploaded.