Trace

Reading code tells you what should happen. Running it tells you what does: the callback nobody mentioned, the job that enqueues two more, the email that goes out twice. That's the gap this fills. The output is a record, in order, of what one scenario did when it ran, with every step marked as seen or only read.

Two ways this fails. You read the code, write it up in the past tense, and it looks exactly like a run — so the reader trusts a guess as much as an observation. Or you run a step that can't be undone: a process gets killed, a database gets dropped. The first is worse, because nothing about it looks wrong.

1. Pin the scenario

The scenario is $ARGUMENTS, or ask for one. It arrives as a sentence ("user creates an account"), a route, a command, a job name.

Turn it into three things before running anything: