Codex Reset Timer

Regression-Test a Codex Workflow With Promptfoo

Measure whether changes to prompts, models, AGENTS.md or Skills improve outcomes across real tasks.

7 min
The short answer

Use a stable task set and assert outcome, files, tools, latency and usage—not subjective vibe.

01

The decision behind the technique

A workflow can look better on one demo while regressing other repositories or failure modes. Repeatable evaluations make tradeoffs visible.

Use a stable task set and assert outcome, files, tools, latency and usage—not subjective vibe.

02

A practical step-by-step workflow

Use this sequence as a default, then tighten or expand it only when the evidence changes.

  • Select representative tasks with known acceptance checks
  • Record the current workflow as a baseline
  • Change one major variable at a time
  • Compare correctness, side effects, latency and usage
03

Failure boundary and finish line

Do not optimize only for pass rate if the new workflow becomes unsafe, expensive or destructive.

Finish when another person can reproduce the check against the exact final state.

Frequently asked questions

What should I do first?+

Select representative tasks with known acceptance checks

What is the main failure mode?+

Do not optimize only for pass rate if the new workflow becomes unsafe, expensive or destructive.

OFFICIAL SOURCES

Verify against the source

Promptfoo coding-agent evaluations

This guide provides general information, not an OpenAI allowance promise or support decision. Your account and official pages govern actual usage, benefits and recovery times.