Update playwright documentation (#11949)

Add security note to playwright tool

libs/langchain/langchain/agents/agent_toolkits/playwright/toolkit.py

@@ -31,7 +31,32 @@ else:
 
 
 class PlayWrightBrowserToolkit(BaseToolkit):
-    """Toolkit for PlayWright browser tools."""
+    """Toolkit for PlayWright browser tools.
+
+    **Security Note**: This toolkit provides code to control a web-browser.
+
+        Careful if exposing this toolkit to end-users. The tools in the toolkit
+        are capable of navigating to arbitrary webpages, clicking on arbitrary
+        elements, and extracting arbitrary text and hyperlinks from webpages.
+
+        Specifically, by default this toolkit allows navigating to:
+
+        - Any URL (including any internal network URLs)
+        - And local files
+
+        If exposing to end-users, consider limiting network access to the
+        server that hosts the agent; in addition, consider it is advised
+        to create a custom NavigationTool wht an args_schema that limits the URLs
+        that can be navigated to (e.g., only allow navigating to URLs that
+        start with a particular prefix).
+
+        Remember to scope permissions to the minimal permissions necessary for
+        the application. If the default tool selection is not appropriate for
+        the application, consider creating a custom toolkit with the appropriate
+        tools.
+
+        See https://python.langchain.com/docs/security for more information.
+    """
 
     sync_browser: Optional["SyncBrowser"] = None
     async_browser: Optional["AsyncBrowser"] = None

libs/langchain/langchain/tools/playwright/navigate.py

@@ -1,12 +1,13 @@
 from __future__ import annotations
 
 from typing import Optional, Type
+from urllib.parse import urlparse
 
 from langchain.callbacks.manager import (
     AsyncCallbackManagerForToolRun,
     CallbackManagerForToolRun,
 )
-from langchain.pydantic_v1 import BaseModel, Field
+from langchain.pydantic_v1 import BaseModel, Field, validator
 from langchain.tools.playwright.base import BaseBrowserTool
 from langchain.tools.playwright.utils import (
     aget_current_page,
@@ -19,9 +20,34 @@ class NavigateToolInput(BaseModel):
 
     url: str = Field(..., description="url to navigate to")
 
+    @validator("url")
+    def validate_url_scheme(cls, url: str) -> str:
+        """Check that the URL scheme is valid."""
+        parsed_url = urlparse(url)
+        if parsed_url.scheme not in ("http", "https"):
+            raise ValueError("URL scheme must be 'http' or 'https'")
+        return url
+
 
 class NavigateTool(BaseBrowserTool):
-    """Tool for navigating a browser to a URL."""
+    """Tool for navigating a browser to a URL.
+
+    **Security Note**: This tool provides code to control web-browser navigation.
+
+        This tool can navigate to any URL, including internal network URLs, and
+        URLs exposed on the server itself.
+
+        However, if exposing this tool to end-users, consider limiting network
+        access to the server that hosts the agent.
+
+        By default, the URL scheme has been limited to 'http' and 'https' to
+        prevent navigation to local file system URLs (or other schemes).
+
+        If access to the local file system is required, consider creating a custom
+        tool or providing a custom args_schema that allows the desired URL schemes.
+
+        See https://python.langchain.com/docs/security for more information.
+    """
 
     name: str = "navigate_browser"
     description: str = "Navigate a browser to the specified URL"