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

Retrospective edition / SAFETY

Insert approval at the side-effect boundary

Classify tools by impact and pause before external messages, purchases, destructive writes, credential use, or privilege changes.

01 / DECIDE

Architecture decision

Use it whenever a model can move from recommending an action to executing it in an external system.

Classify tools by impact and pause before external messages, purchases, destructive writes, credential use, or privilege changes. Map input, output, state, and side effects as one observable path before deciding which layer owns insert approval at the side-effect boundary.

02 / BUILD

Three-step implementation

  1. 01

    Frame the contract

    Write down the caller, data classification, success condition, timeout, cancellation, and ownership. Use it whenever a model can move from recommending an action to executing it in an external system.

  2. 02

    Build one narrow path

    Implement one end-to-end path with request correlation, typed state, and reversible failure handling. Classify tools by impact and pause before external messages, purchases, destructive writes, credential use, or privilege changes.

  3. 03

    Prove the outcome

    Turn acceptance into a repeatable fixture, contract test, or browser test. Audit records connect actor, intent, approval, tool arguments, execution result, and any compensating action.

03 / BOUND

Production boundary

Approval must show exact target, payload, consequences, and reversibility; a generic confirmation is insufficient.

04 / PROVE

Acceptance evidence

Audit records connect actor, intent, approval, tool arguments, execution result, and any compensating action.

SOURCE / HTTP

Reproducible source probe

curl -fsSI 'https://developers.openai.com/api/docs/guides/tools' | sed -n '1,5p'

PRIMARY / OFFICIAL

Official OpenAI sources

Sources checked · 2026-08-10

  1. 01Using tools