Build reliable browser checks using observed UI state, semantic locators, bounded waits, isolated test data and explicit outcome verification.

Browser Automation Use the browser tool already selected by the user or installed in the project. Playwright, Puppeteer and Selenium have different integrations; choose from actual requirements rather than unsupported success rate claims. Modified by AAS maintainers on 2026 09 05: removed unverified comparisons and bypass defaults, clarified waiting and evidence limits. Separate tests of applications you control from interaction with an existing authenticated browser. Do not replace the latter with a fresh unauthenticated session or extract credentials to make an automation test work. Detailed Guide Read [the detailed guide](references/detailed guide.md) before executing this skill. It retains the complete procedure and reference material. Treat its safety, prerequisites, and validation requirements as mandatory. For focused work, load the relevant sections; for end to end work, read the guide completely. Playwright Test Example """ import { test, expect } from '@playwright/test'; // Each test runs in isolated browser context test('user can add item to cart', async ({ page }) = { // Fresh context no cookies, no storage from other tests await page.goto('/products'); await page.getByRole('button', { name: 'Add to Cart' }).click(); await expect(page.getByTestId('cart count')).toHaveText('1'); }); test('user can remove item from cart', async ({ page }) = { // Completely isolated cart is empty await page.goto('/cart'); await expect(page.getByText('Your cart is empty')).toBeVisible(); }); """ Good Examples (User Facing) """ // By role THE BEST CHOICE await page.getByRole('button', { name: 'Submit' }).click(); await page.getByRole('link', { name: 'Sign up' }).click(); await expect(page.getByRole('heading', { name: 'Dashboard' })).toBeVisible(); await page.getByRole('textbox', { name: 'Search' }).fill('query'); // By text content await expect(page.getByText('Welcome back')).toBeVisible(); await page.getByText(/Order \d+/).click(); // Regex supported // By label (forms) await page.getByLabel('Email address').fill('user@example.com'); await page.getByLabel('Password').fill('secret'); // By placeholder await page.getByPlaceholder('Search...').fill('query'); // By test ID (when no user facing option works) await page.getByTestId('submit button').click(); """ Bad Examples (Fragile) """ // DON'T CSS selectors tied to structure await page.locator('.btn primary.submit form').click(); await page.locator(' header div button:nth child(2)').click(); // DON'T XPath tied to structure await page.locator('//div[@class="form"]/button[1]').click(); // DON'T Auto generated selectors await page.locator('[data v 12345]').click(); """ When to Use Use to verify a real browser workflow, diagnose a UI timing failure or collect explicitly authorized page data. Inspect the current page and available tool APIs before selecting locators or actions. Worked example and prerequisites Input: exporting a reviewed JSON file from a local web app. Have the app running, the intended browser available and a synthetic form value. Observe the export control, register the download event before clicking, inspect the downloaded JSON and confirm that editing the input invalidates the old preview. Expected: one file containing the reviewed value, with no hidden project data or network submission. Use explicit desktop/mobile viewports and inspect keyboard/focus behavior when the task includes usability. A locked desktop leaves interactive verification pending; unit tests and headless probes are separate evidence. Limitations Auto waiting checks actionability, not business correctness or successful backend writes. Screenshots, HTML, traces and auth state files may contain private information; capture only the authorized scope. Retrying a read can be safe; retrying checkout, deletion or sending a message may duplicate a side effect. Verify state before repeating it. Resource blocking and mocked responses change the environment and cannot establish unmodified production behavior. Examples require the project’s imports, runner and fixture routes; no browser, service or account is installed by this skill.

browser-automation