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Tools: Claude Code .claudeignore: stop leaking secrets and node_modules into your context - Expert Insights

2026-04-02 0 views admin
Tools: Claude Code .claudeignore: stop leaking secrets and node_modules into your context - Expert Insights

Claude Code .claudeignore: stop leaking secrets and node_modules into your context

What Claude Code reads by default

.claudeignore syntax

The security case for .claudeignore

The performance case

Combining .claudeignore with CLAUDE.md

A complete .claudeignore for a Node.js project

A complete .claudeignore for a Python project

What to keep visible

Check what Claude is reading

Rate limits and context budget

Summary If you've ever watched Claude Code read through thousands of lines of node_modules or seen it suggest changes to your .env file, you've hit one of the most overlooked configuration problems in Claude Code setups. The fix is a .claudeignore file — and most developers don't know it exists. When you run Claude Code in a project directory, it can access everything in that directory. That includes: This burns through your context window fast and introduces security risks when Claude has visibility into secret files. The .claudeignore file uses the same syntax as .gitignore: Place this file in your project root alongside your CLAUDE.md. Even if you trust Claude Code, there's a subtler risk: when Claude reads your .env, that content enters the conversation context. If you're using a proxy or logging tool in the chain, those values can be exposed. Hard rule: always ignore .env and any file containing credentials. Context window space is limited. Every token Claude spends reading node_modules/lodash/index.js is a token it can't use for your actual code. With a .claudeignore, Claude stays focused: For large projects this makes a measurable difference in response quality. Claude gives better answers when it's reading your code, not vendor code. Think of these as two layers: Together they define a clean workspace: Some files should stay visible even if you'd normally gitignore them: Don't over-ignore. The goal is signal-to-noise, not maximum exclusion. You can see what files Claude Code has access to by running: Run this before and after adding .claudeignore to verify it's working. If you're hitting Claude Code's rate limits, a .claudeignore won't directly help — rate limits are per-request, not context-size-based. But it does mean each request is more focused and you need fewer follow-up clarification requests. For teams hitting rate limits regularly, pointing Claude Code at a proxy via ANTHROPIC_BASE_URL removes the caps entirely: SimplyLouie runs at $2/month with no rate limits — useful when .claudeignore alone isn't enough to keep sessions flowing. All three belong in your repo root. Together they give you a Claude Code setup that's focused, secure, and consistent across your team. Add .claudeignore to your next project and run claude --list-files to verify. The context window you save is the context window you keep for actual work. Templates let you quickly answer FAQs or store snippets for re-use. Are you sure you want to ? It will become hidden in your post, but will still be visible via the comment's permalink. as well , this person and/or

Command

Copy

# .claudeignore node_modules/ dist/ build/ .next/ .nuxt/ coverage/ # Secrets .env .env.local .env.production *.pem *.key secrets.json # Logs *.log logs/ # Test artifacts __snapshots__/ .jest-cache/ # Database files *.sqlite *.db dump.sql # Large data files data/ datasets/ *.csv *.json.gz COMMAND_BLOCK: # .claudeignore node_modules/ dist/ build/ .next/ .nuxt/ coverage/ # Secrets .env .env.local .env.production *.pem *.key secrets.json # Logs *.log logs/ # Test artifacts __snapshots__/ .jest-cache/ # Database files *.sqlite *.db dump.sql # Large data files data/ datasets/ *.csv *.json.gz COMMAND_BLOCK: # .claudeignore node_modules/ dist/ build/ .next/ .nuxt/ coverage/ # Secrets .env .env.local .env.production *.pem *.key secrets.json # Logs *.log logs/ # Test artifacts __snapshots__/ .jest-cache/ # Database files *.sqlite *.db dump.sql # Large data files data/ datasets/ *.csv *.json.gz COMMAND_BLOCK: # Secrets — always ignore these .env .env.* *.pem *.p12 *.key credentials.json -weight: 500;">service-account.json COMMAND_BLOCK: # Secrets — always ignore these .env .env.* *.pem *.p12 *.key credentials.json -weight: 500;">service-account.json COMMAND_BLOCK: # Secrets — always ignore these .env .env.* *.pem *.p12 *.key credentials.json -weight: 500;">service-account.json COMMAND_BLOCK: # Before .claudeignore: Claude reads - src/ (your code) - node_modules/ (2M+ lines) - dist/ (compiled output) - .env (secrets) - *.log (debug noise) # After .claudeignore: Claude reads - src/ (your code) - That's it. COMMAND_BLOCK: # Before .claudeignore: Claude reads - src/ (your code) - node_modules/ (2M+ lines) - dist/ (compiled output) - .env (secrets) - *.log (debug noise) # After .claudeignore: Claude reads - src/ (your code) - That's it. COMMAND_BLOCK: # Before .claudeignore: Claude reads - src/ (your code) - node_modules/ (2M+ lines) - dist/ (compiled output) - .env (secrets) - *.log (debug noise) # After .claudeignore: Claude reads - src/ (your code) - That's it. COMMAND_BLOCK: <!-- CLAUDE.md --> # Project conventions - TypeScript strict mode - Tests required for all new functions - Never commit directly to main <!-- .claudeignore excludes everything Claude shouldn't touch --> COMMAND_BLOCK: <!-- CLAUDE.md --> # Project conventions - TypeScript strict mode - Tests required for all new functions - Never commit directly to main <!-- .claudeignore excludes everything Claude shouldn't touch --> COMMAND_BLOCK: <!-- CLAUDE.md --> # Project conventions - TypeScript strict mode - Tests required for all new functions - Never commit directly to main <!-- .claudeignore excludes everything Claude shouldn't touch --> COMMAND_BLOCK: # Dependencies node_modules/ .pnp .pnp.js # Build output dist/ build/ .next/ out/ # Environment and secrets .env .env.local .env.development.local .env.test.local .env.production.local *.pem # Logs -weight: 500;">npm-debug.log* yarn-debug.log* yarn-error.log* *.log # Runtime data pids *.pid *.seed *.pid.lock # Coverage coverage/ .nyc_output # Cache .cache/ .parcel-cache/ .eslintcache # OS files .DS_Store Thumbs.db COMMAND_BLOCK: # Dependencies node_modules/ .pnp .pnp.js # Build output dist/ build/ .next/ out/ # Environment and secrets .env .env.local .env.development.local .env.test.local .env.production.local *.pem # Logs -weight: 500;">npm-debug.log* yarn-debug.log* yarn-error.log* *.log # Runtime data pids *.pid *.seed *.pid.lock # Coverage coverage/ .nyc_output # Cache .cache/ .parcel-cache/ .eslintcache # OS files .DS_Store Thumbs.db COMMAND_BLOCK: # Dependencies node_modules/ .pnp .pnp.js # Build output dist/ build/ .next/ out/ # Environment and secrets .env .env.local .env.development.local .env.test.local .env.production.local *.pem # Logs -weight: 500;">npm-debug.log* yarn-debug.log* yarn-error.log* *.log # Runtime data pids *.pid *.seed *.pid.lock # Coverage coverage/ .nyc_output # Cache .cache/ .parcel-cache/ .eslintcache # OS files .DS_Store Thumbs.db COMMAND_BLOCK: # Virtual environments venv/ env/ .venv/ __pycache__/ *.pyc *.pyo *.pyd # Distribution dist/ build/ *.egg-info/ .eggs/ # Environment .env *.env secrets.py config/secrets.yml # Data data/ datasets/ *.csv *.parquet *.pkl # Notebooks (optional — include if you want Claude editing notebooks) # *.ipynb # Logs *.log logs/ # Testing .pytest_cache/ htmlcov/ .coverage COMMAND_BLOCK: # Virtual environments venv/ env/ .venv/ __pycache__/ *.pyc *.pyo *.pyd # Distribution dist/ build/ *.egg-info/ .eggs/ # Environment .env *.env secrets.py config/secrets.yml # Data data/ datasets/ *.csv *.parquet *.pkl # Notebooks (optional — include if you want Claude editing notebooks) # *.ipynb # Logs *.log logs/ # Testing .pytest_cache/ htmlcov/ .coverage COMMAND_BLOCK: # Virtual environments venv/ env/ .venv/ __pycache__/ *.pyc *.pyo *.pyd # Distribution dist/ build/ *.egg-info/ .eggs/ # Environment .env *.env secrets.py config/secrets.yml # Data data/ datasets/ *.csv *.parquet *.pkl # Notebooks (optional — include if you want Claude editing notebooks) # *.ipynb # Logs *.log logs/ # Testing .pytest_cache/ htmlcov/ .coverage CODE_BLOCK: claude --list-files CODE_BLOCK: claude --list-files CODE_BLOCK: claude --list-files CODE_BLOCK: export ANTHROPIC_BASE_URL=https://simplylouie.com/api/claude CODE_BLOCK: export ANTHROPIC_BASE_URL=https://simplylouie.com/api/claude CODE_BLOCK: export ANTHROPIC_BASE_URL=https://simplylouie.com/api/claude - node_modules/ — millions of lines of vendor code - .env — your API keys, database passwords, secrets - dist/ and build/ — compiled output you don't want edited - *.log files — debug noise - .-weight: 500;">git/ internals — usually irrelevant - CLAUDE.md — tells Claude how to behave (conventions, rules, preferences) - .claudeignore — tells Claude what not to see (files to exclude from context) - README.md — project overview Claude needs - package.json / pyproject.toml — dependency list helps Claude suggest fixes - tsconfig.json — TypeScript config Claude needs to understand your setup - Makefile — if it defines your build commands

🏷️ Tags

toolsutilitiessecurity toolsclaudeclaudeignoreleakingsecretsnode_modulescontextexpert

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