Claude Code beginner

Use .claudeignore to Keep Junk Out of Context

Create a .claudeignore file to prevent Claude Code from reading large generated files, build artifacts, and irrelevant directories that waste your context window.

March 16, 2026

Claude Code reads files to understand your codebase, but some files are pure noise: build output, generated code, giant data files. A .claudeignore file works like .gitignore to keep them out.

Create a .claudeignore

# Build artifacts
dist/
build/
.next/
out/

# Generated files
*.generated.ts
*.min.js
*.min.css
*.map

# Large data
*.csv
*.sql
fixtures/
__snapshots__/

# Dependencies (Claude already ignores node_modules)
vendor/

# Lock files
package-lock.json
yarn.lock
pnpm-lock.yaml

Why This Matters

Every file Claude reads eats context window tokens. A single package-lock.json can be 50K+ tokens. That’s context you could be using for actual code. The .claudeignore keeps your context budget focused on what matters.

Paste into Claude Code

Create a .claudeignore file for this project. Analyze the repo and add patterns for build artifacts, generated files, large data files, lock files, and anything else that shouldn't be read during coding sessions.