Start this session's own Chrome (isolated from every other agent). Optional: the first browser tool call starts one with defaults anyway. Call it explicitly to load a saved login (state), to pick headless/viewport/channel, or to open a URL. A browser started from a state can only visit that state's allowed origins. If this session already had a browser before a reconnect, it is picked up again with its tabs.

Show this session's browser: id, saved state, allowlist, headless, open tabs, uptime.

Relaunch this session's browser keeping cookies, localStorage and open tabs. Pass headless: false to get a visible window (e.g. so the human can watch or solve a captcha), headless: true to hide it again. Pages reload.

Close this session's browser and delete its temporary profile.

Save the current browser's login (cookies + localStorage) as a named state, so other sessions can start already logged in. Only cookies for the allowed origins are kept. allowedOrigins defaults to the http(s) origins open in tabs; it can never be wider than this browser's own allowlist. States a person created with devtools-fleet login cannot be overwritten.

List saved login states: name, allowed origins, cookie counts, when saved and when the first cookie expires. Never shows cookie values.

Clicks on the provided element

Closes the page by its index. The last open page cannot be closed.

Drag an element onto another element

Emulates various features on the target page.

Evaluate a JavaScript function inside the target page. Returns the response as JSON, so returned values have to be JSON-serializable.

Type text into an input, text area or select an option from a element.

Fill out multiple form elements (inputs, selects, checkboxes, radios) at once. ALWAYS prefer this tool over multiple individual 'fill' or 'click' calls when interacting with forms. It is significantly faster, more reliable, and reduces turn count. Example: Fill username, password, and check "Remember Me" in one call.

Gets a console message by its ID. You can get all messages by calling list_console_messages.

Retrieve matched CSS rules, inline styles, inherited styles, and cascade information for an element identified by its UID. Use this tool to debug why specific CSS properties are applied, overridden, or conflicting. Results are paginated and return 10 rules per page by default; use pageIdx to page through the remaining rules. Requires a UID from take_snapshot.

Gets a network request by an optional reqid, if omitted returns the currently selected request in the DevTools Network panel. Useful for inspecting request headers (including 'Cookie') and response headers (including 'Set-Cookie' and directives).

If a browser dialog was opened, use this command to handle it

Hover over the provided element

Get Lighthouse score and reports for accessibility, SEO, best practices, and agentic browsing. This excludes performance. For performance audits, run performance_start_trace

List all console messages for the target page since the last navigation.

Lists the most recent requests for the target page since the last navigation.

Get a list of pages open in the browser.

Go to a URL, or back, forward, or reload. Use project URL if not specified otherwise.

Open a new tab and load a URL. Use project URL if not specified otherwise.

Provides more detailed information on a specific Performance Insight of an insight set that was highlighted in the results of a trace recording.

Start a performance trace on the target webpage. Use to find frontend performance issues, Core Web Vitals (LCP, INP, CLS), and improve page load speed.

Stop the active performance trace recording on the target webpage.

Press a key or key combination. Use this when other input methods like fill() cannot be used (e.g., keyboard shortcuts, navigation keys, or special key combinations).

Resizes the page's window so that the page has specified dimension

Select a page as a context for future tool calls.

Capture a heap snapshot of the target page. Use to analyze the memory distribution of JavaScript objects and debug memory leaks.

Take a screenshot of the page or element.

Take a text snapshot of the target page based on the a11y tree. The snapshot lists page elements along with a unique identifier (uid). Always use the latest snapshot. Prefer taking a snapshot over taking a screenshot. The snapshot indicates the element selected in the DevTools Elements panel (if any).

Type text using keyboard into a previously focused input

Upload a file through a provided element.

Wait for the specified text to appear on the selected page.