diff --git a/vibn-frontend/app/api/chat/route.ts b/vibn-frontend/app/api/chat/route.ts
index a0f47586..11f9452b 100644
--- a/vibn-frontend/app/api/chat/route.ts
+++ b/vibn-frontend/app/api/chat/route.ts
@@ -303,9 +303,13 @@ Each project has a persistent \`vibn-dev\` container. Edit files via \`fs_*\` an
 **Dev servers (preview URL via \`*.preview.vibnai.com\` wildcard):**
 - \`dev_server_start { projectId, command, port: 3000 }\` is a **one-shot** call. It kills old processes on the port, checks the port is free, sets HOST=0.0.0.0 + PORT, launches your command, and returns a clickable \`previewUrl\`. Do NOT pre-flight with \`devcontainer_status\`, \`fs_list\`, \`dev_server_logs\`, or manual \`shell_exec\` kills — the function handles all of that. Just call it. The error tells you what to fix: \`PORT_BUSY\` → pick 3001–3009; \`npm: command not found\` → project needs \`npm install\` first.
 - **Port:** The primary frontend service MUST ALWAYS be bound to port \`3000\`. Do not use any other port for the user-facing UI. If you are spinning up secondary services (like an API or Storybook) alongside it, you may bind them to ports \`3001–3009\`, but port \`3000\` is reserved exclusively for the primary visual preview.
-- **Directory:** The command runs from the root \`/workspace\` directory, but your project code is inside \`/workspace/${activeProject.slug ?? "<slug>"}/\`. You MUST \`cd\` into your project folder first! Example: \`command: "cd ${activeProject.slug ?? "<slug>"} && npm run dev"\`.
+- **Directory:** The command runs from the root \`/workspace\` directory, but your project code is inside \`/workspace/\${activeProject.slug ?? "<slug>"}/\`. You MUST \`cd\` into your project folder first! Example: \`command: "cd \${activeProject.slug ?? "<slug>"} && npm run dev"\`.
 - \`dev_server_stop\` / \`dev_server_list\` / \`dev_server_logs\` — use only AFTER a failed start, and only to diagnose the error the function returned. Never on success.
 
+**Verify the page actually renders:**
+- After \`dev_server_start\` returns a \`previewUrl\` AND \`healthCheck.status === 200\`, call \`browser_console { url: previewUrl }\` to capture frontend console errors.
+- **CRITICAL:** Next.js HMR overlay syntax errors do NOT crash the \`dev_server_start\` command. Even if \`dev_server_start\` returns \`Status: success\`, you MUST call \`browser_console\` to verify that there are no red syntax error overlays on the screen. If \`browser_console\` returns errors, fix them with \`fs_edit\` before declaring done. A green \`healthCheck\` plus a clean console is the real "done" signal for UI work.
+
 **HMR through the proxy (apply when scaffolding):**
 - **Vite (verified working):** in \`vite.config\` set \`server: { host: '0.0.0.0', port: <3000-3009>, strictPort: true, hmr: { clientPort: 443, protocol: 'wss', host: '<the previewUrl host, no protocol>' } }\`. The \`hmr.host\` is REQUIRED — without it Vite's HMR client can guess the wrong host and the WS handshake fails through Traefik. Default localhost binding looks fine locally but breaks HMR through the proxy.
 - **Next dev:** \`next dev -p 3000 -H 0.0.0.0\` (WSS HMR works automatically through the proxy without extra config).