diff --git a/demos/use_cases/vercel-ai-sdk/tests/e2e/api.test.ts b/demos/use_cases/vercel-ai-sdk/tests/e2e/api.test.ts
new file mode 100644
index 00000000..9b787796
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/e2e/api.test.ts
@@ -0,0 +1,95 @@
+import { expect, test } from "@playwright/test";
+
+const CHAT_URL_REGEX = /\/chat\/[\w-]+/;
+const ERROR_TEXT_REGEX = /error|failed|trouble/i;
+
+test.describe("Chat API Integration", () => {
+  test("sends message and receives AI response", async ({ page }) => {
+    await page.goto("/");
+
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Hello");
+    await page.getByTestId("send-button").click();
+
+    // Wait for assistant response to appear
+    const assistantMessage = page.locator("[data-role='assistant']").first();
+    await expect(assistantMessage).toBeVisible({ timeout: 30_000 });
+
+    // Verify it has some text content
+    const content = await assistantMessage.textContent();
+    expect(content?.length).toBeGreaterThan(0);
+  });
+
+  test("redirects to /chat/:id after sending message", async ({ page }) => {
+    await page.goto("/");
+
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Test redirect");
+    await page.getByTestId("send-button").click();
+
+    // URL should change to /chat/:id format
+    await expect(page).toHaveURL(CHAT_URL_REGEX, { timeout: 10_000 });
+  });
+
+  test("clears input after sending", async ({ page }) => {
+    await page.goto("/");
+
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Test message");
+    await page.getByTestId("send-button").click();
+
+    // Input should be cleared
+    await expect(input).toHaveValue("");
+  });
+
+  test("shows stop button during generation", async ({ page }) => {
+    await page.goto("/");
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Test");
+    await page.getByTestId("send-button").click();
+
+    // Stop button should appear during generation
+    const stopButton = page.getByTestId("stop-button");
+    await expect(stopButton).toBeVisible({ timeout: 5000 });
+  });
+});
+
+test.describe("Chat Error Handling", () => {
+  test("handles API error gracefully", async ({ page }) => {
+    await page.route("**/api/chat", async (route) => {
+      await route.fulfill({
+        status: 500,
+        contentType: "application/json",
+        body: JSON.stringify({ error: "Internal server error" }),
+      });
+    });
+
+    await page.goto("/");
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Test error");
+    await page.getByTestId("send-button").click();
+
+    // Should show error toast or message
+    await expect(page.getByText(ERROR_TEXT_REGEX).first()).toBeVisible({
+      timeout: 5000,
+    });
+  });
+});
+
+test.describe("Suggested Actions", () => {
+  test("suggested actions are clickable", async ({ page }) => {
+    await page.goto("/");
+
+    const suggestions = page.locator(
+      "[data-testid='suggested-actions'] button"
+    );
+    const count = await suggestions.count();
+
+    if (count > 0) {
+      await suggestions.first().click();
+
+      // Should redirect after clicking suggestion
+      await expect(page).toHaveURL(CHAT_URL_REGEX, { timeout: 10_000 });
+    }
+  });
+});
diff --git a/demos/use_cases/vercel-ai-sdk/tests/e2e/auth.test.ts b/demos/use_cases/vercel-ai-sdk/tests/e2e/auth.test.ts
new file mode 100644
index 00000000..5dfcbb0a
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/e2e/auth.test.ts
@@ -0,0 +1,31 @@
+import { expect, test } from "@playwright/test";
+
+test.describe("Authentication Pages", () => {
+  test("login page renders correctly", async ({ page }) => {
+    await page.goto("/login");
+    await expect(page.getByPlaceholder("user@acme.com")).toBeVisible();
+    await expect(page.getByLabel("Password")).toBeVisible();
+    await expect(page.getByRole("button", { name: "Sign In" })).toBeVisible();
+    await expect(page.getByText("Don't have an account?")).toBeVisible();
+  });
+
+  test("register page renders correctly", async ({ page }) => {
+    await page.goto("/register");
+    await expect(page.getByPlaceholder("user@acme.com")).toBeVisible();
+    await expect(page.getByLabel("Password")).toBeVisible();
+    await expect(page.getByRole("button", { name: "Sign Up" })).toBeVisible();
+    await expect(page.getByText("Already have an account?")).toBeVisible();
+  });
+
+  test("can navigate from login to register", async ({ page }) => {
+    await page.goto("/login");
+    await page.getByRole("link", { name: "Sign up" }).click();
+    await expect(page).toHaveURL("/register");
+  });
+
+  test("can navigate from register to login", async ({ page }) => {
+    await page.goto("/register");
+    await page.getByRole("link", { name: "Sign in" }).click();
+    await expect(page).toHaveURL("/login");
+  });
+});
diff --git a/demos/use_cases/vercel-ai-sdk/tests/e2e/chat.test.ts b/demos/use_cases/vercel-ai-sdk/tests/e2e/chat.test.ts
new file mode 100644
index 00000000..26cf7531
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/e2e/chat.test.ts
@@ -0,0 +1,61 @@
+import { expect, test } from "@playwright/test";
+
+test.describe("Chat Page", () => {
+  test("home page loads with input field", async ({ page }) => {
+    await page.goto("/");
+    await expect(page.getByTestId("multimodal-input")).toBeVisible();
+  });
+
+  test("can type in the input field", async ({ page }) => {
+    await page.goto("/");
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Hello world");
+    await expect(input).toHaveValue("Hello world");
+  });
+
+  test("submit button is visible", async ({ page }) => {
+    await page.goto("/");
+    await expect(page.getByTestId("send-button")).toBeVisible();
+  });
+
+  test("suggested actions are visible on empty chat", async ({ page }) => {
+    await page.goto("/");
+    const suggestions = page.locator("[data-testid='suggested-actions']");
+    await expect(suggestions).toBeVisible();
+  });
+
+  test("can stop generation with stop button", async ({ page }) => {
+    await page.goto("/");
+
+    // Type and send a message
+    await page.getByTestId("multimodal-input").fill("Hello");
+    await page.getByTestId("send-button").click();
+
+    // Stop button should appear during generation
+    const stopButton = page.getByTestId("stop-button");
+    // If generation starts, stop button appears
+    // This is a best-effort check since timing depends on API
+    await stopButton.click({ timeout: 5000 }).catch(() => {
+      // Generation may have finished before we could click
+    });
+  });
+});
+
+test.describe("Chat Input Features", () => {
+  test("input clears after sending", async ({ page }) => {
+    await page.goto("/");
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Test message");
+    await page.getByTestId("send-button").click();
+
+    // Input should clear after sending
+    await expect(input).toHaveValue("");
+  });
+
+  test("input supports multiline text", async ({ page }) => {
+    await page.goto("/");
+    const input = page.getByTestId("multimodal-input");
+    await input.fill("Line 1\nLine 2\nLine 3");
+    await expect(input).toContainText("Line 1");
+  });
+});
diff --git a/demos/use_cases/vercel-ai-sdk/tests/e2e/model-selector.test.ts b/demos/use_cases/vercel-ai-sdk/tests/e2e/model-selector.test.ts
new file mode 100644
index 00000000..4943796b
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/e2e/model-selector.test.ts
@@ -0,0 +1,69 @@
+import { expect, test } from "@playwright/test";
+
+const MODEL_BUTTON_REGEX = /Gemini|Claude|GPT|Grok/i;
+
+test.describe("Model Selector", () => {
+  test.beforeEach(async ({ page }) => {
+    await page.goto("/");
+  });
+
+  test("displays a model button", async ({ page }) => {
+    // Look for any button with model-related content
+    const modelButton = page.locator("button").filter({ hasText: MODEL_BUTTON_REGEX }).first();
+    await expect(modelButton).toBeVisible();
+  });
+
+  test("opens model selector popover on click", async ({ page }) => {
+    const modelButton = page.locator("button").filter({ hasText: MODEL_BUTTON_REGEX }).first();
+    await modelButton.click();
+
+    // Search input should be visible in the popover
+    await expect(page.getByPlaceholder("Search models...")).toBeVisible();
+  });
+
+  test("can search for models", async ({ page }) => {
+    const modelButton = page.locator("button").filter({ hasText: MODEL_BUTTON_REGEX }).first();
+    await modelButton.click();
+
+    const searchInput = page.getByPlaceholder("Search models...");
+    await searchInput.fill("Claude");
+
+    // Should show at least one Claude model
+    await expect(page.getByText("Claude Haiku").first()).toBeVisible();
+  });
+
+  test("can close model selector by clicking outside", async ({ page }) => {
+    const modelButton = page.locator("button").filter({ hasText: MODEL_BUTTON_REGEX }).first();
+    await modelButton.click();
+
+    await expect(page.getByPlaceholder("Search models...")).toBeVisible();
+
+    // Click outside to close
+    await page.keyboard.press("Escape");
+
+    await expect(page.getByPlaceholder("Search models...")).not.toBeVisible();
+  });
+
+  test("shows model provider groups", async ({ page }) => {
+    const modelButton = page.locator("button").filter({ hasText: MODEL_BUTTON_REGEX }).first();
+    await modelButton.click();
+
+    // Should show provider group headers
+    await expect(page.getByText("Anthropic")).toBeVisible();
+    await expect(page.getByText("Google")).toBeVisible();
+  });
+
+  test("can select a different model", async ({ page }) => {
+    const modelButton = page.locator("button").filter({ hasText: MODEL_BUTTON_REGEX }).first();
+    await modelButton.click();
+
+    // Select a specific model
+    await page.getByText("Claude Haiku").first().click();
+
+    // Popover should close
+    await expect(page.getByPlaceholder("Search models...")).not.toBeVisible();
+
+    // Model button should now show the selected model
+    await expect(page.locator("button").filter({ hasText: "Claude Haiku" }).first()).toBeVisible();
+  });
+});
diff --git a/demos/use_cases/vercel-ai-sdk/tests/fixtures.ts b/demos/use_cases/vercel-ai-sdk/tests/fixtures.ts
new file mode 100644
index 00000000..c782fc0a
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/fixtures.ts
@@ -0,0 +1,15 @@
+import { expect as baseExpect, test as baseTest } from "@playwright/test";
+import { ChatPage } from "./pages/chat";
+
+type Fixtures = {
+  chatPage: ChatPage;
+};
+
+export const test = baseTest.extend<Fixtures>({
+  chatPage: async ({ page }, use) => {
+    const chatPage = new ChatPage(page);
+    await use(chatPage);
+  },
+});
+
+export const expect = baseExpect;
diff --git a/demos/use_cases/vercel-ai-sdk/tests/helpers.ts b/demos/use_cases/vercel-ai-sdk/tests/helpers.ts
new file mode 100644
index 00000000..6d492fac
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/helpers.ts
@@ -0,0 +1,16 @@
+import { generateId } from "ai";
+import { getUnixTime } from "date-fns";
+
+export function generateRandomTestUser() {
+  const email = `test-${getUnixTime(new Date())}@playwright.com`;
+  const password = generateId();
+
+  return {
+    email,
+    password,
+  };
+}
+
+export function generateTestMessage() {
+  return `Test message ${Date.now()}`;
+}
diff --git a/demos/use_cases/vercel-ai-sdk/tests/pages/chat.ts b/demos/use_cases/vercel-ai-sdk/tests/pages/chat.ts
new file mode 100644
index 00000000..22983fa2
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/pages/chat.ts
@@ -0,0 +1,71 @@
+import type { Page } from "@playwright/test";
+
+const MODEL_BUTTON_REGEX = /Gemini|Claude|GPT|Grok/i;
+
+export class ChatPage {
+  page: Page;
+
+  constructor(page: Page) {
+    this.page = page;
+  }
+
+  async goto() {
+    await this.page.goto("/");
+  }
+
+  async createNewChat() {
+    await this.page.goto("/");
+    await this.page.waitForSelector("[data-testid='multimodal-input']");
+  }
+
+  getInput() {
+    return this.page.getByTestId("multimodal-input");
+  }
+
+  async typeMessage(message: string) {
+    const input = this.getInput();
+    await input.fill(message);
+  }
+
+  async sendMessage() {
+    await this.page.getByTestId("send-button").click();
+  }
+
+  async sendUserMessage(message: string) {
+    await this.typeMessage(message);
+    await this.sendMessage();
+  }
+
+  getSendButton() {
+    return this.page.getByTestId("send-button");
+  }
+
+  getStopButton() {
+    return this.page.getByTestId("stop-button");
+  }
+
+  async clickSuggestedAction(index = 0) {
+    const suggestions = this.page.locator(
+      "[data-testid='suggested-actions'] button"
+    );
+    await suggestions.nth(index).click();
+  }
+
+  async openModelSelector() {
+    const modelButton = this.page
+      .locator("button")
+      .filter({ hasText: MODEL_BUTTON_REGEX })
+      .first();
+    await modelButton.click();
+  }
+
+  async selectModel(modelName: string) {
+    await this.openModelSelector();
+    await this.page.getByText(modelName).first().click();
+  }
+
+  async searchModels(query: string) {
+    await this.openModelSelector();
+    await this.page.getByPlaceholder("Search models...").fill(query);
+  }
+}
diff --git a/demos/use_cases/vercel-ai-sdk/tests/prompts/utils.ts b/demos/use_cases/vercel-ai-sdk/tests/prompts/utils.ts
new file mode 100644
index 00000000..83ccf9da
--- /dev/null
+++ b/demos/use_cases/vercel-ai-sdk/tests/prompts/utils.ts
@@ -0,0 +1,30 @@
+import type { LanguageModelV3StreamPart } from "@ai-sdk/provider";
+
+const mockUsage = {
+  inputTokens: { total: 10, noCache: 10, cacheRead: 0, cacheWrite: 0 },
+  outputTokens: { total: 20, text: 20, reasoning: 0 },
+};
+
+export function getResponseChunksByPrompt(
+  _prompt: unknown,
+  includeReasoning = false
+): LanguageModelV3StreamPart[] {
+  const chunks: LanguageModelV3StreamPart[] = [];
+
+  if (includeReasoning) {
+    chunks.push(
+      { type: "reasoning-start", id: "r1" },
+      { type: "reasoning-delta", id: "r1", delta: "Let me think about this." },
+      { type: "reasoning-end", id: "r1" }
+    );
+  }
+
+  chunks.push(
+    { type: "text-start", id: "t1" },
+    { type: "text-delta", id: "t1", delta: "Hello, world!" },
+    { type: "text-end", id: "t1" },
+    { type: "finish", finishReason: "stop", usage: mockUsage }
+  );
+
+  return chunks;
+}