understand-codebase

Recipe for getting oriented in an unfamiliar repository fast - read the README, manifests, and entry points, map the structure, find conventions, trace one request or feature end to end, run the build and tests to learn how things really work, record findings in a notes file for future sessions, identify risks and unknowns, use sub-agents for parallel exploration when it pays off, and stop once the intended change can be made with confidence. Names the skills to apply at each step, the exit check, and what to hand forward. Load when asked to explore, onboard to, audit, or explain a codebase, or before changing code you have not seen.