Fix Playwright Tools bug with Pydantic schemas

libs/community/langchain_community/tools/playwright/base.py

@@ -4,7 +4,7 @@
 
 from langchain_core.tools import BaseTool
 from langchain_core.utils import guard_import
-from pydantic import model_validator
+from pydantic import model_validator, BaseModel
 
 if TYPE_CHECKING:
     from playwright.async_api import Browser as AsyncBrowser
@@ -31,10 +31,14 @@ def lazy_import_playwright_browsers() -> Tuple[Type[AsyncBrowser], Type[SyncBrow
         guard_import(module_name="playwright.sync_api").Browser,
     )
 
+class BaseBrowserToolInput(BaseModel):
+    """Base class for browser tool input when tool has no arguments."""
 
 class BaseBrowserTool(BaseTool):
     """Base class for browser tools."""
 
+    args_schema: Type[BaseModel] = BaseBrowserToolInput
+
     sync_browser: Optional["SyncBrowser"] = None
     async_browser: Optional["AsyncBrowser"] = None
 

libs/community/langchain_community/tools/playwright/current_page.py

@@ -1,12 +1,11 @@
 from __future__ import annotations
 
-from typing import Optional, Type
+from typing import Optional
 
 from langchain_core.callbacks import (
     AsyncCallbackManagerForToolRun,
     CallbackManagerForToolRun,
 )
-from pydantic import BaseModel
 
 from langchain_community.tools.playwright.base import BaseBrowserTool
 from langchain_community.tools.playwright.utils import (
@@ -20,7 +19,6 @@ class CurrentWebPageTool(BaseBrowserTool):
 
     name: str = "current_webpage"
     description: str = "Returns the URL of the current page"
-    args_schema: Type[BaseModel] = BaseModel
 
     def _run(
         self,

libs/community/langchain_community/tools/playwright/extract_text.py

@@ -1,26 +1,24 @@
 from __future__ import annotations
 
-from typing import Any, Optional, Type
+from typing import Any, Optional
 
 from langchain_core.callbacks import (
     AsyncCallbackManagerForToolRun,
     CallbackManagerForToolRun,
 )
-from pydantic import BaseModel, model_validator
+from pydantic import model_validator
 
 from langchain_community.tools.playwright.base import BaseBrowserTool
 from langchain_community.tools.playwright.utils import (
     aget_current_page,
     get_current_page,
 )
 
-
 class ExtractTextTool(BaseBrowserTool):
     """Tool for extracting all the text on the current webpage."""
 
     name: str = "extract_text"
     description: str = "Extract all the text on the current webpage"
-    args_schema: Type[BaseModel] = BaseModel
 
     @model_validator(mode="before")
     @classmethod

libs/community/langchain_community/tools/playwright/navigate_back.py

@@ -1,12 +1,11 @@
 from __future__ import annotations
 
-from typing import Optional, Type
+from typing import Optional
 
 from langchain_core.callbacks import (
     AsyncCallbackManagerForToolRun,
     CallbackManagerForToolRun,
 )
-from pydantic import BaseModel
 
 from langchain_community.tools.playwright.base import BaseBrowserTool
 from langchain_community.tools.playwright.utils import (
@@ -20,7 +19,6 @@ class NavigateBackTool(BaseBrowserTool):
 
     name: str = "previous_webpage"
     description: str = "Navigate back to the previous page in the browser history"
-    args_schema: Type[BaseModel] = BaseModel
 
     def _run(self, run_manager: Optional[CallbackManagerForToolRun] = None) -> str:
         """Use the tool."""

libs/community/tests/unit_tests/tools/playwright/test_all.py

@@ -0,0 +1,18 @@
+"""Test Playwright's Tools."""
+
+from langchain_community.agent_toolkits import PlayWrightBrowserToolkit
+
+from langchain_community.tools.playwright.utils import create_sync_playwright_browser
+
+
+def test_playwright_tools_schemas() -> None:
+    """Test calling 'tool_call_schema' for every tool to check to serialization issues."""
+
+    sync_browser = create_sync_playwright_browser()
+    tools = PlayWrightBrowserToolkit.from_browser(sync_browser=sync_browser).get_tools()
+
+    for tool in tools:
+        try:
+            tool.tool_call_schema
+        except Exception as e:
+            raise AssertionError(f"Error for '{tool.name}' tool: {type(e).__name__}: {e}") from e