codebase-onboarding

Systematically analyze an unfamiliar codebase and produce a structured onboarding guide. Designed for developers joining a new project or setting up Claude Code in an existing repo for the first time. Gather raw signals about the project without reading every file. Run these checks in parallel: From the reconnaissance data, identify: Tech Stack Architecture Pattern Key Directories Map the top-level directories to their purpose: Data Flow Trace one request from entry to response: Identify patterns the codebase already follows: Naming Conventions Code Patterns Git Conventions Produce two outputs: Generate or update a project-specific CLAUDE.md based on detected conventions. If CLAUDE.md already exists, read it first and enhance it — preserve existing project-specific instructions and clearly call out what was added or changed. User : "Onboard me to this codebase" Action : Run full 4-phase workflow → produce Onboarding Guide + Starter CLAUDE.md Output : Onboarding Guide printed directly to the conversation, plus a CLAUDE.md written to the project root User : "Generate a CLAUDE.md for this project" Action : Run Phases 1-3, skip Onboarding Guide, produce only CLAUDE.md Output : Project-specific CLAUDE.md with detected conventions User : "Update the CLAUDE.md with current project conventions" Action : Read existing CLAUDE.md, run Phases 1-3, merge new findings Output : Updated...