frontend-browser-review
by langfuse
Use this skill when a change affects what users see or do in the browser.
npx skills add https://github.com/langfuse/langfuse --skill frontend-browser-reviewFrontend Browser Review
Use this skill when a change affects what users see or do in the browser.
Start Here
- Read
../../../web/AGENTS.mdfor web-specific entry points and test commands. - In Cursor Cloud, use built-in computer use. In local agent environments, use
the workspace
playwrightMCP server from the shared agent setup.
When To Use It
- UI changes in
web/** - Layout, styling, or responsive behavior changes
- Changes to navigation or page flows
- Bug fixes where the failure mode is visible in the browser
- Final signoff for user-visible frontend work
Prefill Test Data First
Most flows are only reviewable against meaningful data. Before opening the
browser, seed what the flow needs with the seed CLI (see the
seed-test-data skill for the need→command table):
pnpm run seed -- trace-tree --observations 5000 --v4— complex observation trees (v3 + v4 events)pnpm run seed -- long-session --traces 300— heavy session viewspnpm run seed -- many-traces --count 100000— list/filter performancepnpm run seed -- doctor— when the stack misbehaves
Every run prints UI deep links — open those instead of navigating manually. Do not hand-write seed scripts or raw ClickHouse inserts.
Review Loop
- Use the existing Cursor Cloud Compose app when available. Otherwise start
the app with
pnpm run dev:webunless a local server is already running. - Install Chromium with
pnpm run playwright:installif Playwright has not been set up on the machine yet. - Open the primary changed flow with Cursor computer use or the Playwright MCP server, using seed-CLI deep links when the flow needs seeded data.
- Exercise the main happy path affected by the change.
- Check for obvious visual regressions:
- broken layout or spacing
- banner overlap or viewport anchoring issues
- missing loading, empty, or error states
- broken responsive behavior on narrow widths
- If the page changed materially, inspect the resulting UI state and compare it against the intended behavior from the task or existing patterns.
- If a Playwright MCP session fails, inspect
/tmp/playwright-mcp. In Cursor Cloud, inspect the run's browser artifacts and Compose logs.
Output Expectations
Report:
- What flow you reviewed
- Whether the primary flow worked
- Any visible regressions or follow-up risks
- If review was blocked, exactly what prevented browser verification
Scope Notes
- This skill complements, not replaces, targeted tests and linting.
- For implementation details, stay in
web/AGENTS.mdand package-local skills. - Use this as the browser-signoff workflow, not as a generic frontend coding guide.