Plan as an artefact
Also called Plan file, Feature list
A plan saved as a file in the repo, with steps that get ticked off, so that it survives the session. A later agent can pick it up, and a reviewer can see what was meant.
A plan in a chat disappears with the chat. In a file, it carries work across sessions and makes drift visible. The hazard is the same as any document: a stale plan gets read as truth, so it has to change when reality does.
Say it to your agent
“Write the plan to docs/plans/webhooks.md as a checklist. After each step, tick it, commit, and add the command you ran with its output. If the plan turns out to be wrong, change the file first and tell me why.”