Overview

UI Verification covers two parallel modes against a live web app:

1. Visual verification — checks whether the page matches its design specification. Translates design claims into CSS rule checks, runs them against the live DOM via getComputedStyle(). Deterministic; the browser's computed styles are the source of truth.
2. Flow verification — checks whether user journeys complete correctly. Executes Gherkin scenarios from .feature files via Nova Act's act() (actions) and act_get() (assertions). Non-deterministic; results vary run-to-run with network timing and live UI shifts.

Both modes share the skill, the MCP server, and the browser session. A single run can produce both kinds of output, combined into one report. Or either mode can run alone; the other section is omitted from the combined report.

Each run produces:

1. Structured artifacts — per-category JSON for visual; per-flow execution data for flows
2. Annotated screenshots — red bounding boxes highlighting visual failures on the page
3. Verification report — markdown combining a visual summary, a flow summary (per-flow status table), and links to per-flow detail reports

The verify_* tools are deterministic — no vision model, browser's computed styles are the source of truth. The compile and audit passes for visual are LLM-driven (best-effort), reconciling design intent against the app's actual structure. Flow steps are interpreted by Nova Act each run; flow runs are inherently non-deterministic.

Reconciliation inputs