Add LangChainToolset

Author: DouweM

pydantic_ai_slim/pydantic_ai/ext/langchain.py

@@ -3,6 +3,7 @@
 from pydantic.json_schema import JsonSchemaValue
 
 from pydantic_ai.tools import Tool
+from pydantic_ai.toolset import FunctionToolset
 
 
 class LangChainTool(Protocol):
@@ -23,7 +24,7 @@ def description(self) -> str: ...
     def run(self, *args: Any, **kwargs: Any) -> str: ...
 
 
-__all__ = ('tool_from_langchain',)
+__all__ = ('tool_from_langchain', 'LangChainToolset')
 
 
 def tool_from_langchain(langchain_tool: LangChainTool) -> Tool:
@@ -59,3 +60,10 @@ def proxy(*args: Any, **kwargs: Any) -> str:
         description=function_description,
         json_schema=schema,
     )
+
+
+class LangChainToolset(FunctionToolset):
+    """A toolset that wraps LangChain tools."""
+
+    def __init__(self, tools: list[LangChainTool]):
+        super().__init__([tool_from_langchain(tool) for tool in tools])

pydantic_ai_slim/pydantic_ai/toolset.py

@@ -46,7 +46,7 @@ class AbstractToolset(ABC, Generic[AgentDepsT]):
 
     @property
     def name(self) -> str:
-        return self.__class__.__name__
+        return self.__class__.__name__.replace('Toolset', ' toolset')
 
     @property
     def name_conflict_hint(self) -> str:
@@ -110,10 +110,6 @@ class FunctionToolset(AbstractToolset[AgentDepsT]):
     max_retries: int = field(default=1)
     tools: dict[str, Tool[Any]] = field(default_factory=dict)
 
-    @property
-    def name(self) -> str:
-        return 'FunctionToolset'
-
     def __init__(self, tools: Sequence[Tool[AgentDepsT] | ToolFuncEither[AgentDepsT, ...]] = [], max_retries: int = 1):
         self.max_retries = max_retries
         self.tools = {}

tests/ext/test_langchain.py

@@ -6,7 +6,7 @@
 from pydantic.json_schema import JsonSchemaValue
 
 from pydantic_ai import Agent
-from pydantic_ai.ext.langchain import tool_from_langchain
+from pydantic_ai.ext.langchain import LangChainToolset, tool_from_langchain
 
 
 @dataclass
@@ -49,31 +49,40 @@ def get_input_jsonschema(self) -> JsonSchemaValue:
         }
 
 
-def test_langchain_tool_conversion():
-    langchain_tool = SimulatedLangChainTool(
-        name='file_search',
-        description='Recursively search for files in a subdirectory that match the regex pattern',
-        args={
-            'dir_path': {
-                'default': '.',
-                'description': 'Subdirectory to search in.',
-                'title': 'Dir Path',
-                'type': 'string',
-            },
-            'pattern': {
-                'description': 'Unix shell regex, where * matches everything.',
-                'title': 'Pattern',
-                'type': 'string',
-            },
+langchain_tool = SimulatedLangChainTool(
+    name='file_search',
+    description='Recursively search for files in a subdirectory that match the regex pattern',
+    args={
+        'dir_path': {
+            'default': '.',
+            'description': 'Subdirectory to search in.',
+            'title': 'Dir Path',
+            'type': 'string',
         },
-    )
+        'pattern': {
+            'description': 'Unix shell regex, where * matches everything.',
+            'title': 'Pattern',
+            'type': 'string',
+        },
+    },
+)
+
+
+def test_langchain_tool_conversion():
     pydantic_tool = tool_from_langchain(langchain_tool)
 
     agent = Agent('test', tools=[pydantic_tool], retries=7)
     result = agent.run_sync('foobar')
     assert result.output == snapshot("{\"file_search\":\"I was called with {'dir_path': '.', 'pattern': 'a'}\"}")
 
 
+def test_langchain_toolset():
+    toolset = LangChainToolset([langchain_tool])
+    agent = Agent('test', toolsets=[toolset], retries=7)
+    result = agent.run_sync('foobar')
+    assert result.output == snapshot("{\"file_search\":\"I was called with {'dir_path': '.', 'pattern': 'a'}\"}")
+
+
 def test_langchain_tool_no_additional_properties():
     langchain_tool = SimulatedLangChainTool(
         name='file_search',

tests/test_tools.py

@@ -589,7 +589,7 @@ def test_tool_return_conflict():
     # this raises an error
     with pytest.raises(
         UserError,
-        match="FunctionToolset defines a tool whose name conflicts with existing tool from OutputToolset: 'ctx_tool'. Consider renaming the tool or wrapping the toolset in a `PrefixedToolset` to avoid name conflicts.",
+        match="Function toolset defines a tool whose name conflicts with existing tool from OutputToolset: 'ctx_tool'. Consider renaming the tool or wrapping the toolset in a `PrefixedToolset` to avoid name conflicts.",
     ):
         Agent('test', tools=[ctx_tool], deps_type=int, output_type=ToolOutput(int, name='ctx_tool'))