Testing & Assertions

Verify page state and generate Playwright locators. Requires the testing capability.

{
  "mcpServers": {
    "playwright": {
      "command": "npx",
      "args": ["@playwright/mcp@latest", "--caps=testing"]
    }
  }
}

Every verify tool returns Done on success and an error message on failure, and records the matching expect(...) line in the generated code so a passing sequence can be assembled into a test.

Verify elements

browser_verify_element_visible

Verify an element is visible on the page, matched by role and accessible name across all frames.

Parameter	Type	Required	Description
role	string	yes	ROLE of the element, as printed in the snapshot: - {ROLE} "Accessible Name":
accessibleName	string	yes	ACCESSIBLE_NAME of the element, as printed in the snapshot: - role "{ACCESSIBLE_NAME}"

→ browser_verify_element_visible { role: "heading", accessibleName: "Dashboard" }
  Done
  // Generated: await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible();

→ browser_verify_element_visible { role: "button", accessibleName: "Submit" }
  Element with role "button" and accessible name "Submit" not found

browser_verify_text_visible

Verify text is visible on the page. Prefer browser_verify_element_visible when the element has a role and name.

Parameter	Type	Required	Description
text	string	yes	TEXT to verify, as printed in the snapshot: - role "Accessible Name": {TEXT} or - text: {TEXT}

→ browser_verify_text_visible { text: "3 items left" }
  Done

browser_verify_list_visible

Verify a list contains the expected items.

Parameter	Type	Required	Description
target	string	yes	Exact element reference that points to the list
element	string	yes	Human-readable list description
items	string[]	yes	Items to verify

→ browser_verify_list_visible {
    element: "Todo list", target: "e8",
    items: ["Buy groceries", "Walk the dog", "Read a book"]
  }
  Done

browser_verify_value

Verify the value of a form element.

Parameter	Type	Required	Description
type	string	yes	textbox, checkbox, radio, combobox, or slider
target	string	yes	Exact element reference from the page snapshot
element	string	yes	Human-readable element description
value	string	yes	Value to verify. For a checkbox or radio use "true" / "false"

→ browser_verify_value { type: "textbox", element: "Email", target: "e3", value: "alice@example.com" }
  Done

→ browser_verify_value { type: "checkbox", element: "Accept terms", target: "e9", value: "true" }
  Done

Generate test code

browser_generate_locator

Generate a Playwright locator for an element, useful when converting exploratory automation into test files.

Parameter	Type	Required	Description
target	string	yes	Element ref or selector

→ browser_generate_locator { target: "e15" }
  getByRole('button', { name: 'Submit' })

→ browser_generate_locator { target: "e3" }
  getByLabel('Email')

Workflow: exploratory testing to test code

Each tool response includes the Playwright code for the action it performed, in the language set by --codegen (typescript by default; also python, java, csharp, or none).

→ browser_navigate { url: "https://demo.playwright.dev/todomvc" }
→ browser_type { target: "e5", text: "Buy groceries", submit: true }
  // Generated: await page.getByPlaceholder('What needs to be done?').fill('Buy groceries');
  // Generated: await page.getByPlaceholder('What needs to be done?').press('Enter');

→ browser_verify_text_visible { text: "Buy groceries" }
  // Generated: await expect(page.getByText('Buy groceries')).toBeVisible();

→ browser_click { target: "e10" }
  // Generated: await page.getByRole('checkbox', { name: 'Toggle Todo' }).click();

→ browser_verify_text_visible { text: "0 items left" }
  // Generated: await expect(page.getByText('0 items left')).toBeVisible();

The generated code can be assembled into a Playwright test:

test('add and complete todo', async ({ page }) => {
  await page.goto('https://demo.playwright.dev/todomvc');
  await page.getByPlaceholder('What needs to be done?').fill('Buy groceries');
  await page.getByPlaceholder('What needs to be done?').press('Enter');
  await expect(page.getByText('Buy groceries')).toBeVisible();
  await page.getByRole('checkbox', { name: 'Toggle Todo' }).click();
  await expect(page.getByText('0 items left')).toBeVisible();
});

Workflow: testing form validation

→ browser_navigate { url: "https://app.example.com/register" }
→ browser_click { target: "e9" }   // Submit empty form
→ browser_verify_text_visible { text: "Email is required" }
  Done

→ browser_type { target: "e3", text: "not-an-email" }
→ browser_click { target: "e9" }
→ browser_verify_text_visible { text: "Please enter a valid email" }
  Done

→ browser_fill_form {
    fields: [
      { name: "Email",            target: "e3", type: "textbox", value: "alice@example.com" },
      { name: "Password",         target: "e5", type: "textbox", value: "password123" },
      { name: "Confirm password", target: "e7", type: "textbox", value: "password456" }
    ]
  }
→ browser_click { target: "e9" }
→ browser_verify_text_visible { text: "Passwords do not match" }
  Done