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Examples:
  • deterministic clicks
  • file handling
  • calling APIs
  • human-in-the-loop
  • browser interactions
  • calling LLMs
  • get 2fa codes
  • send emails
  • Playwright integration (see GitHub example)
Simply add @tools.action(...) to your function.
  • description (required) - What the tool does, the LLM uses this to decide when to call it.
  • allowed_domains - List of domains where tool can run (e.g. ['*.example.com']), defaults to all domains
The Agent fills your function parameters based on their names, type hints, & defaults.
Common Pitfall: Parameter names must match exactly! Use browser_session: BrowserSession (not browser: Browser). The agent injects special parameters by name matching, so using incorrect names will cause your tool to fail silently. See Available Objects below for the correct parameter names.

Available Objects

Your function has access to these objects:
  • browser_session: BrowserSession - Current browser session for CDP access
  • cdp_client - Direct Chrome DevTools Protocol client
  • page_extraction_llm: BaseChatModel - The LLM you pass into agent. This can be used to do a custom llm call here.
  • file_system: FileSystem - File system access
  • available_file_paths: list[str] - Available files for upload/processing
  • has_sensitive_data: bool - Whether action contains sensitive data

Browser Interaction Examples

You can use browser_session to directly interact with page elements using CSS selectors:
Available methods on Page:
  • get_elements_by_css_selector(selector: str) - Returns list of matching elements
  • get_element_by_prompt(prompt: str, llm) - Returns element or None using LLM
  • must_get_element_by_prompt(prompt: str, llm) - Returns element or raises error
Available methods on Element:
  • click() - Click the element
  • type(text: str) - Type text into the element
  • get_text() - Get element text content
  • See browser_use/actor/element.py for more methods

Pydantic Input

You can use Pydantic for the tool parameters:

Domain Restrictions

Limit tools to specific domains:

Advanced Example

For a comprehensive example of custom tools with Playwright integration, see: Playwright Integration Example This shows how to create custom actions that use Playwright’s precise browser automation alongside Browser-Use.

Common Pitfalls

The agent injects special parameters by name, not by type. Using incorrect parameter names is the most common cause of tools failing silently.

❌ Wrong: Using browser: Browser

✅ Correct: Using browser_session: BrowserSession

Key Points

  1. Use browser_session: BrowserSession - not browser: Browser
  2. Use async functions - recommended for consistency with browser operations
  3. Return ActionResult - not plain strings (though strings work, ActionResult provides more control)
  4. Parameter names must match exactly - see Available Objects for the full list of injectable parameters