Audit all environment variable usage in the codebase and generate a complete, documented .env.example. Use when the user says "what env vars do I need?", "document the config", "set up .env.example", or when onboarding someone new to the project.

Generate a structured mental model of an unfamiliar codebase — entry points, data flow, key abstractions, and gotchas. Use when starting on a new repo, when the user says "explain this codebase", "how does this work", "onboard me", or before making large changes to unfamiliar code.