2 2
3[← All use cases](https://developers.openai.com/codex/use-cases)3[← All use cases](https://developers.openai.com/codex/use-cases)
4 4
5Copy page [Export as PDF](https://developers.openai.com/codex/use-cases/codebase-onboarding/?export=pdf)
6
5Use Codex to map unfamiliar codebases, explain different modules and data flow, and point you to the next files worth reading before you edit.7Use Codex to map unfamiliar codebases, explain different modules and data flow, and point you to the next files worth reading before you edit.
6 8
7Easy9Easy
19 21
20## Starter prompt22## Starter prompt
21 23
24Explain how the request flows through <name of the system area> in the codebase.
25 Include:
26 - which modules own what
27 - where data is validated
28 - the top gotchas to watch for before making changes
29 End with the files I should read next.
30
22Explain how the request flows through <name of the system area> in the codebase.31Explain how the request flows through <name of the system area> in the codebase.
23 Include:32 Include:
24 - which modules own what33 - which modules own what