codebase-onboarding
Analyze an unfamiliar codebase and generate a structured onboarding guide with architecture map, key entry points, conventions, and a starter CODEX.md. Use when joining a new project or setting up OpenAI Codex for the first time in a repo.
npx skills add mturac/everything-openai-codex --skill codebase-onboarding --agent codex
Same command for any agent — swap --agent for claude-code, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Codebase Onboarding Systematically analyze an unfamiliar codebase and produce a structured onboarding guide. Designed for developers joining a new project or setting up OpenAI Codex in an existing repo for the first time. ## When to Use - First time opening a project with OpenAI Codex - Joining a new team or repository - User asks "help me understand this codebase" - User asks to generate a CODEX.md for a project - User says "onboard me" or "walk me through this repo" ## How It Works ### Phase 1: Reconnaissance Gather raw signals about the project without reading every file. Run these checks in parallel: ``` 1. Package manifest detection → package.json, go.mod, Cargo.toml, pyproject.toml, pom.xml, build.gradle, Gemfile, composer.json, mix.exs, pubspec.yaml 2. Framework fingerprinting → next.config.*, nuxt.config.*, angular.json, vite.config.*, django settings, flask app factory, fastapi main, rails config 3. Entry point identification → main.*, index.*, app.*, server.*, cmd/, src/main/ 4. Directory structure snapshot → Top 2 levels of the directory tree, ignoring node_modules, vendor, .git, dist, build, __pycache__, .next 5. Config and tooling detection → .eslintrc*, .prettierrc*
- When to Use
- How It Works
- Phase 1: Reconnaissance
- Phase 2: Architecture Mapping
- Phase 3: Convention Detection
- Phase 4: Generate Onboarding Artifacts
- Best Practices
- Anti-Patterns to Avoid
- Examples
- Example 1: First time in a new repo
- Example 2: Generate CODEX.md for existing project
- Example 3: Enhance existing CODEX.md
What does the codebase-onboarding skill do?
Analyze an unfamiliar codebase and generate a structured onboarding guide with architecture map, key entry points, conventions, and a starter CODEX.md. Use when joining a new project or setting up OpenAI Codex for the first time in a repo.
How do I install it?
Run `npx skills add mturac/everything-openai-codex --skill codebase-onboarding --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From mturac/everything-openai-codex, a repository with 84 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.