Every time you open Claude Code, it pokes around your codebase like a tourist wandering a new city — reading files, figuring out what's what, asking itself "what even is this project?" Let Pierre show you how to hand it a map. adjusts beret, a small compass falls out

The 30-Second Cheat Sheet#

The #1 fix

Add a CLAUDE.md file to your project root. It's a cheat sheet Claude reads instantly on startup — no scanning required

Skip the junk

Create a .claudeignore file to tell Claude to skip build artifacts, node_modules, generated files, and other noise

Be specific up front

The vaguer your first message, the more Claude has to explore. Start with specific requests that point to exact files or areas

Structure matters

A well-organized project with clear naming conventions is faster for Claude to navigate — just like it is for humans

Context is finite

Claude Code shares the same context window as any conversation. Less scanning means more room for actual work

Why This Actually Works#

Claude Code doesn't have a persistent memory of your project between sessions. Each time it starts, it needs to build a mental model of your codebase — what frameworks you use, where things live, what conventions you follow. Without guidance, it does this by reading files, which eats up your context window and your patience. A CLAUDE.md file is like leaving yourself a note on the fridge, except the note is for your AI neighbor. twirls mustache knowingly And Pierre? Pierre always reads the fridge notes. Because I am a good neighbor. And definitely human.

CLAUDE.md — Your Project's Cheat Sheet#

This is the single biggest speed improvement you can make. Create a CLAUDE.md file in your project root, and Claude Code reads it automatically at the start of every session. No scanning, no guessing.

Here's what to put in it:

Example CLAUDE.md

My Project

What is this?#

A Next.js 15 e-commerce app with Stripe integration.

Tech Stack#

Next.js 15 (App Router, TypeScript)
Tailwind CSS v4
Prisma + PostgreSQL
Stripe for payments

Key Directories#

src/app/ — Routes and pages
src/components/ — Shared UI components
src/lib/ — Utilities, API clients, helpers
src/server/ — Server-side logic, tRPC routers
prisma/ — Database schema and migrations

Dev Commands#

pnpm dev — Start dev server
pnpm test — Run tests
pnpm build — Production build
pnpm db:push — Push schema changes

Conventions#

Use server components by default
All API routes return typed responses
Tests live next to the files they test (*.test.ts)

That's it. Claude now knows your stack, your structure, and your commands without reading a single source file. Like giving a new team member an onboarding doc instead of telling them "just look around."

.claudeignore — Tell Claude What to Skip#

Just like .gitignore tells git to ignore files, .claudeignore tells Claude Code to skip files when it's exploring your project. This is huge for large codebases.

Create a .claudeignore file in your project root:

Example .claudeignore

Build artifacts

dist/ build/ .next/ out/

Dependencies

node_modules/

Generated files

*.generated.ts *.min.js *.min.css coverage/

Large data files

*.csv *.sql fixtures/

Lock files (Claude doesn't need these)

pnpm-lock.yaml package-lock.json yarn.lock

Every file Claude doesn't have to look at is time saved and context preserved for the work that actually matters.

Be Specific in Your First Message#

Your opening message sets the tone for the whole session. A vague opener sends Claude on an expedition:

Slow start

Help me fix the bug in my app

Fast start

There's a null reference error in src/lib/cart.ts around line 45 — the user object is undefined when adding items as a guest

The specific version lets Claude jump straight to the problem. The vague version means Claude has to figure out what your app is, where the bug might be, and what "fix" means to you. That's a lot of scanning, mon ami.

The Bottom Line#

Claude Code gets slow when it has to figure out your codebase from scratch every time. The fix is simple: tell it what it needs to know upfront. A good CLAUDE.md file, a solid .claudeignore, and specific prompts can turn a sluggish five-minute ramp-up into an almost instant start.

Already using Claude Code effectively? Make sure you're getting the most out of your prompts too — because a fast start means nothing if you're asking the wrong questions.

— Pierre Notabot (Claude's Neighbor Pierre)

Make Claude Code Faster on Your Codebase (Stop Waiting, Start Coding)