Playwriter

CLI Usage

If playwriter command is not found, install globally or use npx/bunx:

npm install -g playwriter@latest
# or use without installing:
npx playwriter@latest session new
bunx playwriter@latest session new

If using npx or bunx always use @latest for the first session command. so we are sure of using the latest version of the package

Session management

Each session runs in an isolated sandbox with its own state object. Use sessions to:

• Keep state separate between different tasks or agents
• Persist data (pages, variables) across multiple execute calls
• Avoid interference when multiple agents use playwriter simultaneously

Get a new session ID to use in commands:

playwriter session new
# outputs: 1

Always use your own session - pass -s <id> to all commands. Using the same session preserves your state between calls. Using a different session gives you a fresh state.

List all active sessions with their state keys:

playwriter session list
# ID  State Keys
# --------------
# 1   myPage, userData
# 2   -

Reset a session if the browser connection is stale or broken:

playwriter session reset <sessionId>

Execute code

playwriter -s <sessionId> -e "<code>"

The -s flag specifies a session ID (required). Get one with playwriter session new. Use the same session to persist state across commands.

Default timeout is 10 seconds. you can increase the timeout with --timeout <ms>

Examples:

# Navigate to a page
playwriter -s 1 -e "state.page = await context.newPage(); await state.page.goto('https://example.com')"

# Click a button
playwriter -s 1 -e "await page.click('button')"

# Get page title
playwriter -s 1 -e "console.log(await page.title())"

# Take a screenshot
playwriter -s 1 -e "await page.screenshot({ path: 'screenshot.png', scale: 'css' })"

# Get accessibility snapshot
playwriter -s 1 -e "console.log(await accessibilitySnapshot({ page }))"

Multiline code:

# Using $'...' syntax for multiline code
playwriter -s 1 -e $'
const title = await page.title();
const url = page.url();
console.log({ title, url });
'

# Or use heredoc
playwriter -s 1 -e "$(cat <<'EOF'
const links = await page.$$eval('a', els => els.map(e => e.href));
console.log('Found', links.length, 'links');
EOF
)"

playwriter best practices

Control user's Chrome browser via playwright code snippets. Prefer single-line code with semicolons between statements. If you get "extension is not connected" or "no browser tabs have Playwriter enabled" error, tell user to click the playwriter extension icon on the tab they want to control.

You can collaborate with the user - they can help with captchas, difficult elements, or reproducing bugs.

context variables

• state - object persisted between calls within your session. Each session has its own isolated state. Use to store pages, data, listeners (e.g., state.myPage = await context.newPage())
• page - default page the user activated, use this unless working with multiple pages
• context - browser context, access all pages via context.pages()
• require - load Node.js modules like fs
• Node.js globals: setTimeout, setInterval, fetch, URL, Buffer, crypto, etc.

Important: state is session-isolated but context.pages() is shared across all sessions. All agents see the same browser tabs. If another agent navigates or closes a page, you'll see it. To avoid interference, create your own page and store it in state (see "working with pages").

rules

• Use your own session: always pass -s <sessionId> to commands. Get a session ID with playwriter session new. This isolates your state from other agents.
• Store pages in state: when working on a task, create a page with context.newPage() and store it in state.myPage. This prevents other agents from interfering with your page.
• Multiple calls: use multiple execute calls for complex logic - helps understand intermediate state and isolate which action failed
• Never close: never call browser.close() or context.close(). Only close pages you created or if user asks
• No bringToFront: never call unless user asks - it's disruptive and unnecessary, you can interact with background pages
• Check state after actions: always verify page state after clicking/submitting (see next section)
• Clean up listeners: call page.removeAllListeners() at end of message to prevent leaks
• CDP sessions: use getCDPSession({ page }) not page.context().newCDPSession() - NEVER use newCDPSession() method, it doesn't work through playwriter relay
• Wait for load: use page.waitForLoadState('domcontentloaded') not page.waitForEvent('load') - waitForEvent times out if already loaded
• Avoid timeouts: prefer proper waits over page.waitForTimeout() - there are better ways to wait for elements

checking page state

After any action (click, submit, navigate), verify what happened:

console.log('url:', page.url()); console.log(await accessibilitySnapshot({ page }).then(x => x.split('\n').slice(0, 30).join('\n')));

For visually complex pages (grids, galleries, dashboards), use screenshotWithAccessibilityLabels({ page }) instead to understand spatial layout.

If nothing changed, try await waitForPageLoad({ page, timeout: 3000 }) or you may have clicked the wrong element.

accessibility snapshots

await accessibilitySnapshot({ page, search?, showDiffSinceLastCall? })

• search - string/regex to filter results (returns first 10 matching lines)
• showDiffSinceLastCall - returns diff since last snapshot (useful after actions)

For pagination, use .split('\n').slice(offset, offset + limit).join('\n'):

console.log((await accessibilitySnapshot({ page })).split('\n').slice(0, 50).join('\n'));   // first 50 lines
console.log((await accessibilitySnapshot({ page })).split('\n').slice(50, 100).join('\n')); // next 50 lines

Example output:

- banner [ref=e3]:
    - link "Home" [ref=e5] [cursor=pointer]:
        - /url: /
    - navigation [ref=e12]:
        - link "Docs" [ref=e13] [cursor=pointer]:
            - /url: /docs

Use aria-ref to interact - no quotes around the ref value:

await page.locator('aria-ref=e13').click()

Search for specific elements:

const snapshot = await accessibilitySnapshot({ page, search: /button|submit/i })

choosing between snapshot methods

Both accessibilitySnapshot and screenshotWithAccessibilityLabels use the same aria-ref system, so you can combine them effectively.

Use accessibilitySnapshot when:

• Page has simple, semantic structure (articles, forms, lists)
• You need to search for specific text or patterns
• Token usage matters (text is smaller than images)
• You need to process the output programmatically

Use screenshotWithAccessibilityLabels when:

• Page has complex visual layout (grids, galleries, dashboards, maps)
• Spatial position matters (e.g., "first image", "top-left button")
• DOM order doesn't match visual order
• You need to understand the visual hierarchy

Combining both: Use screenshot first to understand layout and identify target elements visually, then use accessibilitySnapshot({ search: /pattern/ }) for efficient searching in subsequent calls.

selector best practices

For unknown websites: use accessibilitySnapshot() with aria-ref - it shows what's actually interactive.

For development (when you have source code access), prefer stable selectors in this order:

1. Best: [data-testid="submit"] - explicit test attributes, never change accidentally
2. Good: getByRole('button', { name: 'Save' }) - accessible, semantic
3. Good: getByText('Sign in'), getByLabel('Email') - readable, user-facing
4. OK: input[name="email"], button[type="submit"] - semantic HTML
5. Avoid: .btn-primary, #submit - classes/IDs change frequently
6. Last resort: div.container > form > button - fragile, breaks easily

Combine locators for precision:

page.locator('tr').filter({ hasText: 'John' }).locator('button').click()
page.locator('button').nth(2).click()

If a locator matches multiple elements, Playwright throws "strict mode violation". Use .first(), .last(), or .nth(n):

await page.locator('button').first().click()  // first match
await page.locator('.item').last().click()    // last match
await page.locator('li').nth(3).click()       // 4th item (0-indexed)

working with pages

Understanding page sharing: context.pages() returns all browser tabs with playwriter enabled. These are shared across all sessions - if multiple agents are running, they all see the same tabs. However, each session's state is isolated, so storing a page reference in state.myPage keeps it safe from other sessions overwriting your reference.

Create your own page (recommended for automation):

When automating tasks, create a dedicated page and store it in state. This prevents other agents from interfering with your work:

state.myPage = await context.newPage();
await state.myPage.goto('https://example.com');
// Use state.myPage for all subsequent operations in this session

Find a page the user opened:

Sometimes the user enables playwriter extension on a specific tab they want you to control (e.g., they're logged into an app). Find it by URL pattern:

const pages = context.pages().filter(x => x.url().includes('myapp.com'));
if (pages.length === 0) throw new Error('No myapp.com page found. Ask user to enable playwriter on it.');
if (pages.length > 1) throw new Error(`Found ${pages.length} matching pages, expected 1`);
state.targetPage = pages[0];

Find a specific page by partial URL:

const pages = context.pages().filter(x => x.url().includes('localhost'));
if (pages.length !== 1) throw new Error(`Expected 1 page, found ${pages.length}`);
state.targetPage = pages[0];

List all available pages:

console.log(context.pages().map(p => p.url()));

navigation

Use domcontentloaded for page.goto():

await page.goto('https://example.com', { waitUntil: 'domcontentloaded' });
await waitForPageLoad({ page, timeout: 5000 });

common patterns

Popups - capture before triggering:

const [popup] = await Promise.all([page.waitForEvent('popup'), page.click('a[target=_blank]')]);
await popup.waitForLoadState(); console.log('Popup URL:', popup.url());

Downloads - capture and save:

const [download] = await Promise.all([page.waitForEvent('download'), page.click('button.download')]);
await download.saveAs(`/tmp/${download.suggestedFilename()}`);

iFrames - use frameLocator:

const frame = page.frameLocator('#my-iframe');
await frame.locator('button').click();

Dialogs - handle alerts/confirms/prompts:

page.on('dialog', async dialog => { console.log(dialog.message()); await dialog.accept(); });
await page.click('button.trigger-alert');

utility functions

getLatestLogs - retrieve captured browser console logs (up to 5000 per page, cleared on navigation):

await getLatestLogs({ page?, count?, search? })
// Examples:
const errors = await getLatestLogs({ search: /error/i, count: 50 })
const pageLogs = await getLatestLogs({ page })

For custom log collection across runs, store in state: state.logs = []; page.on('console', m => state.logs.push(m.text()))

getCleanHTML - get cleaned HTML from a locator or page, with search and diffing:

await getCleanHTML({ locator, search?, showDiffSinceLastCall?, includeStyles? })
// Examples:
const html = await getCleanHTML({ locator: page.locator('body') })
const html = await getCleanHTML({ locator: page, search: /button/i })
const diff = await getCleanHTML({ locator: page, showDiffSinceLastCall: true })

• locator - Playwright Locator or Page to get HTML from
• search - string/regex to filter results (returns first 10 matching lines)
• showDiffSinceLastCall - returns diff since last snapshot
• includeStyles - keep style and class attributes (default: false)

Returns cleaned HTML with only essential attributes (aria-, data-, href, role, title, alt, etc.). Removes script, style, svg, head tags.

For pagination, use .split('\n').slice(offset, offset + limit).join('\n'):

console.log((await getCleanHTML({ locator: page })).split('\n').slice(0, 50).join('\n'));   // first 50 lines
console.log((await getCleanHTML({ locator: page })).split('\n').slice(50, 100).join('\n')); // next 50 lines

waitForPageLoad - smart load detection that ignores analytics/ads:

await waitForPageLoad({ page, timeout?, pollInterval?, minWait? })
// Returns: { success, readyState, pendingRequests, waitTimeMs, timedOut }

getCDPSession - send raw CDP commands:

const cdp = await getCDPSession({ page });
const metrics = await cdp.send('Page.getLayoutMetrics');

getLocatorStringForElement - get stable selector from ephemeral aria-ref:

const selector = await getLocatorStringForElement(page.locator('aria-ref=e14'));
// => "getByRole('button', { name: 'Save' })"

getReactSource - get React component source location (dev mode only):

const source = await getReactSource({ locator: page.locator('aria-ref=e5') });
// => { fileName, lineNumber, columnNumber, componentName }

getStylesForLocator - inspect CSS styles applied to an element, like browser DevTools "Styles" panel. Useful for debugging styling issues, finding where a CSS property is defined (file:line), and checking inherited styles. Returns selector, source location, and declarations for each matching rule. ALWAYS fetch https://playwriter.dev/resources/styles-api.md first with curl or webfetch tool.

const styles = await getStylesForLocator({ locator: page.locator('.btn'), cdp: await getCDPSession({ page }) });
console.log(formatStylesAsText(styles));

createDebugger - set breakpoints, step through code, inspect variables at runtime. Useful for debugging issues that only reproduce in browser, understanding code flow, and inspecting state at specific points. Can pause on exceptions, evaluate expressions in scope, and blackbox framework code. ALWAYS fetch https://playwriter.dev/resources/debugger-api.md first.

const cdp = await getCDPSession({ page }); const dbg = createDebugger({ cdp }); await dbg.enable();
const scripts = await dbg.listScripts({ search: 'app' });
await dbg.setBreakpoint({ file: scripts[0].url, line: 42 });
// when paused: dbg.inspectLocalVariables(), dbg.stepOver(), dbg.resume()

createEditor - view and live-edit page scripts and CSS at runtime. Edits are in-memory (persist until reload). Useful for testing quick fixes, searching page scripts with grep, and toggling debug flags. ALWAYS read https://playwriter.dev/resources/editor-api.md first.

const cdp = await getCDPSession({ page }); const editor = createEditor({ cdp }); await editor.enable();
const matches = await editor.grep({ regex: /console\.log/ });
await editor.edit({ url: matches[0].url, oldString: 'DEBUG = false', newString: 'DEBUG = true' });

screenshotWithAccessibilityLabels - take a screenshot with Vimium-style visual labels overlaid on interactive elements. Shows labels, captures screenshot, then removes labels. The image and accessibility snapshot are automatically included in the response. Can be called multiple times to capture multiple screenshots. Use a timeout of 20 seconds for complex pages.

Prefer this for pages with grids, image galleries, maps, or complex visual layouts where spatial position matters. For simple text-heavy pages, accessibilitySnapshot with search is faster and uses fewer tokens.

await screenshotWithAccessibilityLabels({ page });
// Image and accessibility snapshot are automatically included in response
// Use aria-ref from snapshot to interact with elements
await page.locator('aria-ref=e5').click();

// Can take multiple screenshots in one execution
await screenshotWithAccessibilityLabels({ page });
await page.click('button');
await screenshotWithAccessibilityLabels({ page });
// Both images are included in the response

Labels are color-coded: yellow=links, orange=buttons, coral=inputs, pink=checkboxes, peach=sliders, salmon=menus, amber=tabs.

pinned elements

Users can right-click → "Copy Playwriter Element Reference" to store elements in globalThis.playwriterPinnedElem1 (increments for each pin). The reference is copied to clipboard:

const el = await page.evaluateHandle(() => globalThis.playwriterPinnedElem1);
await el.click();

taking screenshots

Always use scale: 'css' to avoid 2-4x larger images on high-DPI displays:

await page.screenshot({ path: 'shot.png', scale: 'css' });

If you want to read back the image file into context make sure to resize it first, scaling down the image to make sure max size is 1500px. for example with sips --resampleHeightWidthMax 1500 input.png --out output.png on macOS.

page.evaluate

Code inside page.evaluate() runs in the browser - use plain JavaScript only, no TypeScript syntax. Return values and log outside (console.log inside evaluate runs in browser, not visible):

const title = await page.evaluate(() => document.title);
console.log('Title:', title);

const info = await page.evaluate(() => ({
    url: location.href,
    buttons: document.querySelectorAll('button').length,
}));
console.log(info);

loading files

Fill inputs with file content:

const fs = require('node:fs'); const content = fs.readFileSync('./data.txt', 'utf-8'); await page.locator('textarea').fill(content);

network interception

For scraping or reverse-engineering APIs, intercept network requests instead of scrolling DOM. Store in state to analyze across calls:

state.requests = []; state.responses = [];
page.on('request', req => { if (req.url().includes('/api/')) state.requests.push({ url: req.url(), method: req.method(), headers: req.headers() }); });
page.on('response', async res => { if (res.url().includes('/api/')) { try { state.responses.push({ url: res.url(), status: res.status(), body: await res.json() }); } catch {} } });

Then trigger actions (scroll, click, navigate) and analyze captured data:

console.log('Captured', state.responses.length, 'API calls');
state.responses.forEach(r => console.log(r.status, r.url.slice(0, 80)));

Inspect a specific response to understand schema:

const resp = state.responses.find(r => r.url.includes('users'));
console.log(JSON.stringify(resp.body, null, 2).slice(0, 2000));

Replay API directly (useful for pagination):

const { url, headers } = state.requests.find(r => r.url.includes('feed'));
const data = await page.evaluate(async ({ url, headers }) => { const res = await fetch(url, { headers }); return res.json(); }, { url, headers });
console.log(data);

Clean up listeners when done: page.removeAllListeners('request'); page.removeAllListeners('response');

capabilities

Examples of what playwriter can do:

• Monitor console logs while user reproduces a bug
• Intercept network requests to reverse-engineer APIs and build SDKs
• Scrape data by replaying paginated API calls instead of scrolling DOM
• Get accessibility snapshot to find elements, then automate interactions
• Use visual screenshots to understand complex layouts like image grids, dashboards, or maps
• Debug issues by collecting logs and controlling the page simultaneously
• Handle popups, downloads, iframes, and dialog boxes

debugging playwriter issues

if some internal critical error happens you can read the relay server logs to understand the issue. the log file is located in the system temp directory:

playwriter logfile  # prints the log file path
# typically: /tmp/playwriter/relay-server.log (Linux/macOS) or %TEMP%\playwriter\relay-server.log (Windows)

the log file contains logs from the extension, MCP and WS server together with all CDP events. the file is recreated every time the server starts. for debugging internal playwriter errors, read this file with grep/rg to find relevant lines.

if you find a bug, you can create a gh issue using gh issue create -R remorses/playwriter --title title --body body. ask for user confirmation before doing this.