mastermind-browser-verification

Mastermind browser verification

An agent that says "I checked it in the browser and it works" has produced no evidence. The claim cannot be re-read, cannot be compared against the next run, and cannot be distinguished from not having looked.

Browser checks are worth running. They just have to leave something behind.

The accessibility tree is the evidence; the screenshot is not

Read the page as an accessibility tree, not as an image. The tree is text: it can be quoted in the report, diffed against the next run, and checked against a criterion like "the disabled control is not focusable" or "the empty state renders". A screenshot proves nothing to anything downstream — it is for a human to look at, and it belongs in the report as an attachment, never as the basis of a claim.

Concretely: assert on roles, names, and states from the tree. "Submit button present, disabled state set, error text Card expired associated with the input" is evidence. "Looks right" is not.

Console and network errors are mechanical failures

Read console messages filtered to errors, and network requests for failed responses. A page that throws during render, or 404s on an asset, has failed — that is not a matter of taste and does not need a screenshot to establish.

Record the count and the messages. A clean console is itself an observation worth recording, because next week's run will want something to compare against.

Viewports and colour scheme are a checklist, not a vibe

Resize deliberately and record each result: mobile, tablet, desktop, and the dark scheme if the product has one. "Responsive" as a bare claim means the agent did not resize. Three recorded observations at three widths mean it did.

If a viewport was not checked, it is not checked — see below.

Record what you checked and what you did not

Every browser observation goes into the report with its scope:

### Browser observations
- `read_page` at 375px — nav collapsed to a menu button; primary CTA present and enabled.
- Console — 0 errors, 0 warnings.
- Network — no failed requests.
- Dark scheme — **not checked** (no dark palette in this change).
- Visual fidelity against the frame — **not checked** (needs human review).