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DevTools

Built-in developer tools — console logs, network requests, JS errors, performance, cookies, and viewport control. No second tool needed.

get_console_logs

Get browser console logs (errors, warnings, info, log).

get_console_logs(clear: bool = False) -> str

Parameters

Name Type Default Description
clear bool False If True, clears the captured logs after returning them.

Returns

Console Logs:
[ERROR] Uncaught TypeError: Cannot read property 'map' of undefined (app.js:42)
[WARNING] React: Each child in a list should have a unique "key" prop. (bundle.js:1042)
[INFO] WebSocket connected to ws://localhost:3001 (socket.js:18)

Behavior

  • Returns the last 50 captured messages.
  • Includes level, text, and source location.
  • Logs are accumulated across the session unless clear=True.

get_network_requests

Get captured network requests (API calls, images, scripts, etc.).

get_network_requests(num_requests: int | None = None, clear: bool = False) -> str

Parameters

Name Type Default Description
num_requests int \| None None (→ 30) How many of the most recent requests to return.
clear bool False If True, clears the captured requests after returning them.

Returns

Network Requests:
GET https://api.example.com/users -> 200 (142ms)
POST https://api.example.com/login -> 200 (89ms)
GET https://api.example.com/avatar/me.jpg -> 404 (12ms)

Why this is good

Requests are paired by request identity, not URL string. You won't see "phantom 404s" caused by deduplication bugs that lose the timing data.

get_page_errors

Get uncaught JavaScript errors with stack traces.

get_page_errors() -> str

Returns

Page Errors:
 Uncaught TypeError: Cannot read property 'map' of undefined
   at renderList (app.js:42:15)
   at HTMLButtonElement.onClick (app.js:88:5)

run_in_console

Eval JavaScript with structured error handling. Returns the result plus a fresh annotated screenshot.

run_in_console(code: str) -> tuple[str, Image]

Parameters

Name Type Description
code str JavaScript code to eval in the page context.

Returns

Console Result:
{"id": 7, "tag": "button", "text": "Sign in"}

Found 5 interactive elements:
  [1] input - Search…
  ...

When to use

  • Inspect a variable without typing a full run_javascript extraction.
  • Trigger a UI change and then immediately see the new state in the screenshot.
  • Test if a piece of code throws.

inspect_element

Inspect an element to get its computed styles, dimensions, attributes, and properties.

inspect_element(element_id: int) -> str

Parameters

Name Type Description
element_id int The number label of the element to inspect.

Returns

Element 5 Inspection:
  Tag: <button>
  ID: #submit
  Classes: .btn.btn-primary
  Text: Sign in
  Size: 96x40px
  Position: (832, 412)
  Styles:
    color: rgb(255, 255, 255)
    background: rgb(13, 110, 253)
    font: 16px Inter, sans-serif

Why this is good

  • Computed styles — what the browser actually rendered, not what's in the stylesheet.
  • Bounding box — useful for figuring out why a click landed in the wrong place.
  • Attributes — first 10 attributes shown.

get_page_performance

Get page performance metrics: TTFB, First Contentful Paint, load time, resource count, JS heap.

get_page_performance() -> str

Returns

Page Performance:
  Time to First Byte: 87ms
  First Contentful Paint: 412ms
  DOM Content Loaded: 678ms
  Load Complete: 1230ms
  Resources Loaded: 47
  JS Heap: 28MB / 128MB

get_cookies

Get all cookies in the current browser context.

get_cookies() -> str

Returns

Cookies:
  session=eyJhbGciOiJIUzI1N... (domain=.example.com)
  csrf_token=abc123def456... (domain=example.com)

Set a cookie.

set_cookie(name: str, value: str, domain: str | None = None, path: str = "/") -> str

Parameters

Name Type Default Description
name str — Cookie name.
value str — Cookie value.
domain str \| None None Cookie domain. Auto-inferred from the current page URL when omitted.
path str "/" Cookie path.

Examples

→ set_cookie("session", "abc123")                        # domain inferred from current page
→ set_cookie("auth", "xyz789", domain=".example.com")    # explicit domain

Delete cookies by name across all domains in the current context.

delete_cookie(name: str) -> str

clear_cookies

Wipe all cookies in the current context.

clear_cookies() -> str

set_viewport

Resize the browser viewport on the fly. Great for responsive testing.

set_viewport(width: int, height: int) -> tuple[str, Image]

Parameters

Name Type Description
width int Width in pixels.
height int Height in pixels.

Examples

→ set_viewport(1920, 1080)        # desktop full-HD
→ set_viewport(390, 844)          # iPhone 14
→ set_viewport(768, 1024)         # iPad portrait

Common device presets

Device Width × Height
iPhone SE 375 × 667
iPhone 14 390 × 844
iPhone 14 Pro Max 430 × 932
Pixel 7 412 × 915
iPad 768 × 1024
iPad Pro 1024 × 1366
Desktop HD 1920 × 1080

About:blank first

If you get an error, navigate to about:blank first, then resize, then navigate to your target.

See also