Read code you didn't write without guessing

Reading a repository from the first file to the last is rarely useful. Begin with a behavior you can name, find its entry point, and follow data until the system produces an observable result.

Pause at boundaries: authentication, validation, persistence, external calls, and state transitions. Those seams reveal more about the architecture than reading every local helper in sequence.

Tests often show which outcomes the original author considered important, which dependencies are intentionally isolated, and which edge cases have caused pain before. Read a focused test beside the implementation instead of treating the test suite as a final verification button.

Then inspect a failure path. Happy-path code explains what the feature wants; error handling explains what the system is prepared to survive.

Search and coding agents are excellent for locating call sites, summarizing unfamiliar modules, and proposing a traversal. Treat those answers as a map legend, then open the referenced code and verify the relationships that matter.

For a structured daily discovery loop, codebase-coffee on GitHub builds a repo-specific curriculum and points each brief back to real files. It is most useful for important concepts you would not think to ask about during an urgent task.

Explain the flow in your own words, predict which test a small change would affect, and make one bounded edit when appropriate. Those steps expose gaps that passive recognition can hide.

EraCode supports the active side with coding, quiz, terminal, and multi-part practice. If the code is heavily agent-authored, continue with [how to take ownership of an AI-written codebase](/ai-wrote-my-codebase).