Acceptance criteria

Acceptance criteria are the checkable conditions that define done for a task. Written as a short list of observable outcomes, what the user can do and what the test proves, they turn a vague request into something you and the agent can agree on and verify.

For agent work they do double duty: the brief the agent builds against, and the checklist you review against. A plan card might carry a few lines:

- [ ] A logged-out visitor can request a reset link
- [ ] The link expires after 30 minutes
- [ ] Tests cover the expiry path

Write them before any code and they double as the test list, which keeps scope from drifting mid-task.