Use CLAUDE.md to Persist Project Conventions Across Claude AI Sessions

A Reddit user reports that adding a CLAUDE.md file to the project root is the single highest-leverage change they've made with Claude Code. Claude reads this file at the start of every session, so you never need to re-explain conventions like TypeScript usage, Tailwind vs. CSS modules, test folder structure, or data model relationships.

Key Details

• Placement: Create a file named CLAUDE.md in the root of your project directory.
• What to include: Coding conventions (e.g., "We use TypeScript, always. No default exports. Tailwind, not CSS modules. Tests go in tests folders."), plus project architecture context — how modules connect, data models, and which files are critical vs. scaffolding.
• Behavior: The file is read automatically at the start of every Claude session. No manual invocation needed. Conventions are applied without being asked.
• Result: The user noticed "Claude's edits got noticeably better once it had that context baked in from the start of the session."

Practical Example

# CLAUDE.md

Conventions

Language: TypeScript
Exports: named exports only (no default exports)
Styling: Tailwind CSS (no CSS modules)
Testing: tests go in dedicated tests/ folders

Architecture

Frontend: React with React Router
API layer: Express routes in /api
Data models: Prisma schema in /prisma
Critical files: /src/app.ts, /src/config.ts

After adding this file, the user reports never having to retype those rules per session.

Who It's For

Developers using Claude Code or any Claude-powered coding agent who want consistent behavior across chat sessions without repeating instructions.