GPT WORLD / INDEPENDENT CODEX FIELD MANUAL Source review · 2026-07-31

Retrospective edition / CODEX

Start Codex in a bounded repository

The working directory, task, sandbox, approval policy, and definition of done should be explicit before the coding agent edits files.

01 / DECIDE

Architecture decision

Use it for repository inspection, implementation, debugging, tests, and review where terminal evidence matters.

The working directory, task, sandbox, approval policy, and definition of done should be explicit before the coding agent edits files. Map input, output, state, and side effects as one observable path before deciding which layer owns start codex in a bounded repository.

02 / BUILD

Three-step implementation

  1. 01

    Frame the contract

    Write down the caller, data classification, success condition, timeout, cancellation, and ownership. Use it for repository inspection, implementation, debugging, tests, and review where terminal evidence matters.

  2. 02

    Build one narrow path

    Implement one end-to-end path with request correlation, typed state, and reversible failure handling. The working directory, task, sandbox, approval policy, and definition of done should be explicit before the coding agent edits files.

  3. 03

    Prove the outcome

    Turn acceptance into a repeatable fixture, contract test, or browser test. Completion evidence includes the inspected diff, relevant tests, remaining risks, and no unrelated user changes overwritten.

03 / BOUND

Production boundary

Do not grant broad write, network, or destructive authority before the exact task and verification path are understood.

04 / PROVE

Acceptance evidence

Completion evidence includes the inspected diff, relevant tests, remaining risks, and no unrelated user changes overwritten.

SOURCE / HTTP

Reproducible source probe

curl -fsSI 'https://developers.openai.com/codex/cli' | sed -n '1,5p'

PRIMARY / OFFICIAL

Official OpenAI sources

Sources checked · 2026-08-10

  1. 01Codex CLI