Claude Code vs Codex CLI

Map entry points before a risky change

Claude Code handles this as a draft: Scripts, main files, and the test command in the README. Do not push.

Steps: 4
Cost: low
Time: Half an hour

Unverified · code.claude.com · 16 Oct 2026

Refactor one module and land tests in the same session

Claude Code reads a single module, writes characterization tests, then changes structure only where those tests pass.

Steps: 5
Cost: low
Time: Several hours on a module you already understand well enough to review.

Unverified · code.claude.com · 15 Oct 2026

Check a README's commands against the repo

Claude Code handles this as a draft: Which commands are missing a script entry. Do not rewrite the README until I agree.

Steps: 4
Cost: low
Time: Half an hour

Unverified · code.claude.com · 14 Oct 2026

Upgrade one dependency and read the changelog first

Claude Code summarizes breaking changes for a single dependency, applies the upgrade, and runs the existing tests. Major bumps stay behind a question.

Steps: 4
Cost: low
Time: The changelog reading and the mechanical codemod, not the production watch afterward.

Unverified · code.claude.com · 12 Oct 2026

List upgrade steps from a changelog

Claude Code handles this as a draft: Breaking changes that mention the version I am on. Do not run the upgrade.

Steps: 4
Cost: low
Time: Forty minutes

Unverified · code.claude.com · 8 Oct 2026

Map a repo for someone who cloned it this morning

Claude Code writes a one-page map of how to run, test, and change the system. It does not edit application code.

Steps: 4
Cost: low
Time: A half day of wandering for a new teammate, if the map is checked by someone who already knows the repo.

Unverified · code.claude.com · 2 Oct 2026

Review dependency licenses I exported

Claude Code handles this as a draft: Which ones are not on the allow list I wrote. Do not add packages.

Steps: 4
Cost: low
Time: Half an hour

Unverified · code.claude.com · 12 Sep 2026

Codex CLI playbooks

Outline an API change for one field

Codex CLI handles this as a draft: Old, new, and who reads it in the snippets I paste. Do not ship the API.

Steps: 4
Cost: low
Time: Forty minutes

Unverified · learn.chatgpt.com · 15 Oct 2026

Draft a test plan for a bug

Codex CLI handles this as a draft: Cases, including the one that should fail today. Do not merge.

Steps: 4
Cost: low
Time: Half an hour

Unverified · learn.chatgpt.com · 14 Oct 2026

Point Codex CLI at one failing check

Codex CLI investigates a single red check, patches it, and shows the command output. It does not rewrite the suite to go green.

Steps: 4
Cost: low
Time: The first hypothesis and the mechanical fix, when the failure is already reproduced locally.

Unverified · learn.chatgpt.com · 14 Oct 2026

List error paths in a handler

Codex CLI handles this as a draft: What the user sees for each branch. Do not deploy.

Steps: 4
Cost: low
Time: Half an hour

Unverified · learn.chatgpt.com · 11 Oct 2026

Implement a small feature that already has acceptance notes

Codex CLI builds a feature described as observable behavior, runs the tests you name, and leaves unrelated files alone.

Steps: 4
Cost: low
Time: A focused implementation pass when acceptance notes already exist.

Unverified · learn.chatgpt.com · 18 Sep 2026

Find dead flags in a config file

Codex CLI handles this as a draft: Flags with no reference in the search I paste. Do not delete them.

Steps: 4
Cost: low
Time: Half an hour

Unverified · learn.chatgpt.com · 12 Sep 2026