Codebase Onboarding

Systematically analyze an unfamiliar codebase and produce a structured onboarding guide.

Phase 1: Reconnaissance

Gather raw signals about the project without reading every file. Glob these six checks in parallel at the top two levels of the tree (ignore node_modules, vendor, .git, dist, build, __pycache__, .next). Record found or absent. Do not invent ecosystems that are not on disk. Read a file only when a signal is ambiguous.

1. Package manifest - package.json, go.mod, Cargo.toml, pyproject.toml, pom.xml, build.gradle, Gemfile, composer.json, mix.exs, pubspec.yaml
2. Framework fingerprint - next.config.*, nuxt.config.*, angular.json, vite.config.*, django settings, flask app factory, fastapi main, rails config
3. Entry points - main.*, index.*, app.*, server.*, cmd/, src/main/
4. Directory snapshot - top 2 levels of the tree, same ignore list as above
5. Config and tooling - .eslintrc*, .prettierrc*, tsconfig.json, Makefile, Dockerfile, docker-compose*, .github/workflows/, .env.example, CI configs
6. Test structure - tests/, test/, __tests__/, *_test.go, *.spec.ts, *.test.js, pytest.ini, jest.config.*, vitest.config.*

Done when: each of the six recon checks has a result (found or absent).

Phase 2: Architecture Mapping