diff --git a/AGENTS.md b/AGENTS.md
index eb8e961..bccff3e 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -144,3 +144,43 @@ node test.js
 - Add or extend APIs on **`window.LAMBS`** inside `index.html`.
 - Document JSON field changes here under **Using LAMBS** (`reportVersion` bumps if breaking).
 - Prefer **Copy JSON** / `lambsReportToJSON` over new DOM scraping hooks.
+
+---
+
+## Cursor Cloud specific instructions
+
+LAMBS is a **zero-backend** product: one `index.html` file runs entirely in the browser. No database, API server, or Docker is required.
+
+### Verify logic (CI-equivalent)
+
+```bash
+node test.js
+```
+
+Requires **Node.js only** — no `pnpm install`. CI uses Node 24; Node 22+ works locally.
+
+There is **no lint command** configured (no ESLint/Prettier in the repo).
+
+### Run the application
+
+Open `index.html` in a browser (`file://` or static server). For a headless UI smoke test covering **both** tabs (Single mAb Analysis + Multiple mAb Analysis with built-in example sequences):
+
+```bash
+pnpm install
+pnpm exec playwright install chromium   # one-time per VM; not in update script
+node scripts/verify-ui.mjs
+```
+
+This loads the Trastuzumab example on the Single tab, runs **Analyze**, then switches to Multiple mAb Analysis, loads the 4-sequence example CSV, runs **Cluster & Analyze**, and saves screenshots under `LAMBS_UI_OUT` (default `/opt/cursor/artifacts/screenshots`).
+
+Or serve statically: `python3 -m http.server 8080 --directory /workspace` → `http://localhost:8080/index.html`.
+
+### Optional dev dependencies
+
+For README screenshots:
+
+```bash
+pnpm screenshots
+```
+
+Python 3 scripts under `scripts/` regenerate embedded germline/stats data in `index.html`; only needed when changing those datasets, not for normal dev/test.
diff --git a/package.json b/package.json
index 10352e3..d5cf271 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,8 @@
   "description": "LAMBS - Local Analysis of mAb Sequences",
   "scripts": {
     "release": "commit-and-tag-version --config ./scripts/version-updater/versionrc.cjs",
-    "screenshots": "node scripts/capture-readme-screenshots.mjs"
+    "screenshots": "node scripts/capture-readme-screenshots.mjs",
+    "verify-ui": "node scripts/verify-ui.mjs"
   },
   "devDependencies": {
     "commit-and-tag-version": "12.7.1",
diff --git a/scripts/verify-ui.mjs b/scripts/verify-ui.mjs
new file mode 100644
index 0000000..c7ed219
--- /dev/null
+++ b/scripts/verify-ui.mjs
@@ -0,0 +1,103 @@
+/**
+ * Headless browser smoke test for LAMBS UI (Single + Multiple mAb Analysis tabs).
+ *
+ * Prerequisites:
+ *   pnpm install
+ *   pnpm exec playwright install chromium
+ *
+ * Usage:
+ *   node scripts/verify-ui.mjs
+ *   LAMBS_UI_OUT=/path/to/dir node scripts/verify-ui.mjs
+ */
+import { mkdirSync } from "node:fs";
+import { join, dirname } from "node:path";
+import { fileURLToPath, pathToFileURL } from "node:url";
+import { chromium } from "playwright";
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const REPO_ROOT = join(__dirname, "..");
+const INDEX_URL = pathToFileURL(join(REPO_ROOT, "index.html")).href;
+const OUT_DIR = process.env.LAMBS_UI_OUT || "/opt/cursor/artifacts/screenshots";
+
+mkdirSync(OUT_DIR, { recursive: true });
+
+function assert(condition, message) {
+  if (!condition) throw new Error(message);
+}
+
+const browser = await chromium.launch({ headless: true });
+
+try {
+  const page = await browser.newPage({ viewport: { width: 1200, height: 1220 } });
+  await page.goto(INDEX_URL, { waitUntil: "domcontentloaded" });
+
+  // --- Single mAb Analysis ---
+  console.log("=== Single mAb Analysis tab ===");
+  await page.evaluate(() => {
+    switchTab("single");
+    loadExampleSingle();
+    analyze();
+  });
+  await page
+    .locator("#results")
+    .getByText(/germline|VH|VL|liability/i)
+    .first()
+    .waitFor({ timeout: 15000 });
+
+  const singleApi = await page.evaluate(() => {
+    const r = LAMBS.analyzeMabReportFromRaw(
+      document.getElementById("vh-input").value,
+      document.getElementById("vl-input").value
+    );
+    if (!r.ok) return { ok: false, errors: r.errors };
+    return {
+      ok: true,
+      kind: r.report.kind,
+      vhVGene: r.report.chains.vh.variable.germline.vGene?.gene,
+      vlVGene: r.report.chains.vl.variable.germline.vGene?.gene,
+    };
+  });
+  console.log(JSON.stringify(singleApi, null, 2));
+  assert(singleApi.ok && singleApi.kind === "single-mab", "Single tab analysis failed");
+
+  const singleShot = join(OUT_DIR, "lambs-single-analysis-demo.png");
+  await page.screenshot({ path: singleShot, fullPage: false });
+  console.log("Screenshot:", singleShot);
+
+  // --- Multiple mAb Analysis ---
+  console.log("\n=== Multiple mAb Analysis tab ===");
+  await page.evaluate(() => {
+    switchTab("multi");
+    loadExampleCSV();
+    runMultiAnalysis();
+  });
+  await page
+    .locator("#multi-results")
+    .getByText(/cluster|alignment|consensus/i)
+    .first()
+    .waitFor({ timeout: 15000 });
+
+  const multiApi = await page.evaluate(() => ({
+    basketCount: typeof basket !== "undefined" ? basket.length : 0,
+    clusterReport: LAMBS.lastClusterReport
+      ? {
+          kind: LAMBS.lastClusterReport.kind,
+          inputCount: LAMBS.lastClusterReport.inputCount,
+          clusterCount: LAMBS.lastClusterReport.clusterCount,
+          firstClusterSize: LAMBS.lastClusterReport.clusters?.[0]?.size,
+        }
+      : null,
+  }));
+  console.log(JSON.stringify(multiApi, null, 2));
+  assert(multiApi.basketCount === 4, "Expected 4 example sequences in basket");
+  assert(multiApi.clusterReport?.kind === "cluster", "Multi tab cluster report missing");
+  assert(multiApi.clusterReport.clusterCount >= 1, "Expected at least one cluster");
+
+  const multiShot = join(OUT_DIR, "lambs-multiple-analysis-demo.png");
+  await page.screenshot({ path: multiShot, fullPage: false });
+  console.log("Screenshot:", multiShot);
+
+  console.log("\nUI verification passed (Single + Multiple mAb Analysis).");
+} finally {
+  await browser.close();
+}