claire vo
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Build and test a Codex skill that checks a codebase before you start coding

Bitmap software modules arranged around a test tray, with a green check marking the selected module.
tested-agent-skills-pixel.png
Bitmap software modules arranged around a test tray, with a green check marking the selected module.
Original imagedownload .png ↓
Codex + GitHub + Node.js

I wanted to reuse the checks we do when starting work on a codebase: can an agent figure out how to install it, run it, and test a change? A Codex skill is saved instructions, sometimes with helper scripts, that an agent can use again. This was one of a set I made for repeat engineering work.

  1. I asked Codex to turn those checks into a skill, including scripts to inspect the project and tests using sample repositories.
  2. I had a second agent try the skill on our own site. It found a test command that existed but wasn’t running in the automated checks.
  3. That trial also exposed a gap in the skill: it missed instructions in the parent repository. Codex fixed the scanner and added a test for that case.

The next time I start work on a project, I can ask Codex to run that skill. The instructions and checks are already there, including what we learned from trying it on our own code.