01 / REPORead before editing
Inspect status, ownership instructions, neighboring modules, and the user's current diff. Scope comes from the codebase, not a generic pattern.
Give Codex a repo contract and demand observable proof.
Codex is most useful when it can inspect the real workspace, follow local engineering rules, split bounded work, and test what it changed. The course builds that operating discipline around AGENTS.md, the terminal, diffs, and browser evidence.
What belongs in AGENTS.md
- Product boundary
- The user, behavior, and nearby surfaces that must remain unchanged while a task is in scope.
- Repo conventions
- Existing libraries, ownership lines, file patterns, and commands Codex should prefer over inventing a parallel system.
- Safety gates
- Protected data, destructive actions, paid services, public deploys, and outbound operations that require an explicit stop.
- Proof standard
- Tests, link checks, responsive routes, screenshots, and exact evidence needed before the work can be called complete.
Work at three levels
02 / TASKDelegate bounded research
Use parallel agents for independent discovery or validation, then keep edits coordinated through one clear owner and a shared definition of done.
03 / SURFACEVerify where users feel it
Pair unit or static checks with the rendered route, interaction, network state, and viewport that exercise the changed behavior.
Codex artifact
A completion packet, not a status claim
- Scoped diff with unrelated user changes preserved
- Commands run and the important pass or failure result
- Browser route and viewport evidence for user-facing work
- Known gaps, assumptions, or checks that could not run
- Clear file references for the next reviewer
Use one real task as the lab.
Builder covers the complete Codex workflow. Operator adds reviewed production-agent evidence. A Direct Call can repair the rules and verification path in an active repo.