Codex is not an assistant. It is an autonomous engineer that opens pull requests on your behalf, running in an isolated sandbox, reading your code, running your tests, and handing back a diff. Learn to work with one in 12 short lessons.
A few sentences describing what you want done: a clear goal, a tight scope, and real acceptance criteria.
It clones your repo into a fresh sandbox, reads, edits, runs tests, and retries. No network access unless you grant it.
You receive a patch, a summary of what it did, and the test output. You review it like any human PR: approve, comment, and merge.
Work through the tracks in order the first time, as each track builds on the last. You can come back to individual lessons as references when you are mid-task and something is not landing.
Every lesson you finish earns a badge. Every checkpoint inside earns XP, which persists in your browser. Keep it open while you practice on a real task at work.
Start at lesson 01. It takes ten minutes and will change how you write every task after.