Config file recognition

Config File Recognition

When to Use This Skill

When you need to understand how a project is configured, what external services it depends on, what environment variables it requires, or whether there are configuration issues (hardcoded secrets, missing defaults, inconsistent settings).

Step-by-Step Investigation

Step 1: Find All Config Files

Use glob_search to locate config files across the project:

• glob_search(pattern="**/.env*") — environment files
• glob_search(pattern="**/*.json", path="config/") — JSON config
• glob_search(pattern="**/Dockerfile*") — container config
• glob_search(pattern="**/*.yaml") or **/*.yml — YAML config
• glob_search(pattern="**/requirements*.txt") — Python dependencies
• glob_search(pattern="**/package.json") — Node.js dependencies

Step 2: Read Safe Config Files First

Read in this priority order:

1. .env.example — safe to read, shows what variables the app expects
2. config/ directory files — JSON/YAML config for services, servers, etc.
3. requirements.txt / package.json — dependencies reveal what services are used
4. Dockerfile / docker-compose.yml — runtime environment, ports, services

Never read .env files — they may contain real secrets.

Step 3: Grep for Configuration Patterns in Code

Use grep_search to understand how config is consumed:

• grep_search(query="os.getenv|os.environ|dotenv") — find env var usage in Python
• grep_search(query="process.env") — find env var usage in JavaScript/Node
• grep_search(query="localhost|127.0.0.1") — find hardcoded local URLs
• grep_search(query="port|PORT") — find port configuration
• grep_search(query="SECRET|KEY|TOKEN|PASSWORD") — check for sensitive values in code

Step 4: Map External Dependencies

From the config files and grep results, build a picture of:

• Required environment variables — list each with its purpose (from .env.example and getenv calls)
• External services — databases, APIs, caches (from connection strings and config)
• Ports — what ports the app listens on and connects to
• API keys / credentials needed — which services require authentication

Step 5: Check for Issues

Look for common configuration problems:

• Hardcoded secrets — API keys, passwords, or tokens directly in source code (not in env vars)
• Missing .env.example — if code uses env vars but no example file documents them
• Inconsistent ports — frontend configured to call one port, backend listening on another
• Hardcoded URLs — localhost or IP addresses that won't work in production
• Unpinned dependencies — requirements.txt without version pins

Report Format

Structure your findings as:

1. Config Files Found — list with brief purpose of each
2. Environment Variables — table of variable name, purpose, where it's used
3. External Services — what the app connects to and how
4. Ports & URLs — network configuration summary
5. Issues Found — any problems discovered (hardcoded secrets, missing config, etc.)

Things to Avoid

• Never read .env files — they contain real secrets
• Never display actual secret values even if found in code — just note their location
• Don't assume config values are current — they might be defaults overridden at runtime
• Don't confuse requirements.txt (dependencies) with config.yaml (runtime settings)