name	claude-code-customization
description	Customizing Claude Code with CLAUDE.md
category	ai
tags	["claude","configuration","customization","project-setup"]
models	["sonnet","opus"]
version	1.0.0
created	"2026-05-14T00:00:00.000Z"

Claude Code Customization

Tailor Claude Code's behavior per-project using CLAUDE.md configuration files.

Quick Start

# CLAUDE.md — Project Configuration for Claude Code

## Project Overview
E-commerce platform built with Next.js, Prisma, and PostgreSQL.
Uses tRPC for API routes and Zod for validation.

## Code Conventions
- React components: functional with hooks, no class components
- API routes: tRPC routers in src/server/routers/
- Database: Prisma with migrations in prisma/
- Testing: Vitest with React Testing Library
- Types: strict TypeScript, no `any`

## Commands
- Build: `npm run build`
- Test: `npm run test`
- Lint: `npm run lint`
- Dev: `npm run dev`
- Type-check: `npm run typecheck`

## Architecture
- /src/app — Next.js App Router pages
- /src/components — Shared React components
- /src/server — tRPC server routers and middleware
- /prisma — Database schema and migrations
- /public — Static assets

## Preferences
- Use path aliases (@/ for src/)
- Prefer async/await over raw promises
- Use `zod` for all input validation

Key Concepts

CLAUDE.md files act as system prompts for Claude Code. Place them at the project root or in subdirectories for scoped configuration. Include project overview, conventions, commands, architecture, and any critical constraints.

When to Use

Setting up a new project for AI-assisted development
Onboarding Claude Code to large existing codebases
Enforcing project-specific patterns and conventions

Validation

Claude Code sessions respect the defined conventions
Claude uses correct commands from the config
Claude follows the specified architecture patterns in new code