feat: evaluator runtime verification for web projects, optional Playwright docs

README.md

@@ -151,6 +151,22 @@ Before the loop starts, `/loop-plan` generates contracts for each story. These d
   archive/                       # Completed feature archives
 ```
 
+## Browser Testing (Optional)
+
+The evaluator includes basic runtime verification for web projects (starts a local server, checks HTTP response). For full browser testing with console error detection and screenshots, install the Playwright MCP server:
+
+```bash
+claude mcp add playwright npx @playwright/mcp@latest --headless --browser=chromium
+```
+
+When Playwright is available, the evaluator will use it to:
+- Navigate to the running application
+- Check for JavaScript console errors
+- Take screenshots for visual verification
+- Reject stories with runtime errors
+
+This is optional — the evaluator works without it, but may miss runtime issues that only surface in a browser.
+
 ## Design Principles
 
 - **Fresh context per iteration** — no accumulated hallucination drift