End-to-end scenario testing

Verify that a running application does what it claims, by driving its real interface the way a user would. The unit of work is a scenario card: a short markdown test written for an agent to execute — not a Playwright/expect script. Cards are high-level enough that a small UI shuffle doesn't invalidate them, but precise enough that two agents running the same card reach the same verdict.

A green unit test proves the wiring in isolation. A scenario proves the wiring as assembled and rendered. They catch different bugs — write the card even when the unit tests pass.

When to use this