langgraph[patch]: ToolNode support for tools outputting msg (#977)

ToolNode passes ToolCall to tools directly and outputs the generated ToolMessages directly

libs/langgraph/langgraph/prebuilt/tool_node.py

@@ -1,5 +1,4 @@
 import asyncio
-import json
 from typing import Any, Callable, Dict, Literal, Optional, Sequence, Union
 
 from langchain_core.messages import AIMessage, AnyMessage, ToolCall, ToolMessage
@@ -11,20 +10,11 @@ from langchain_core.tools import tool as create_tool
 from langgraph.utils import RunnableCallable
 
 
-def str_output(output: Any) -> str:
-    if isinstance(output, str):
-        return output
-    else:
-        try:
-            return json.dumps(output)
-        except Exception:
-            return str(output)
-
-
 class ToolNode(RunnableCallable):
-    """A node that runs the tools requested in the last AIMessage. It can be used
-    either in StateGraph with a "messages" key or in MessageGraph. If multiple
-    tool calls are requested, they will be run in parallel. The output will be
+    """A node that runs the tools called in the last AIMessage.
+
+    It can be used either in StateGraph with a "messages" key or in MessageGraph. If
+    multiple tool calls are requested, they will be run in parallel. The output will be
     a list of ToolMessages, one for each tool call.
 
     The `ToolNode` is roughly analogous to:
@@ -79,14 +69,13 @@ class ToolNode(RunnableCallable):
 
         def run_one(call: ToolCall):
             try:
-                output = self.tools_by_name[call["name"]].invoke(call["args"], config)
+                input = {**call, **{"type": "tool_call"}}
+                return self.tools_by_name[call["name"]].invoke(input, config)
             except Exception as e:
                 if not self.handle_tool_errors:
                     raise e
-                output = f"Error: {repr(e)}\n Please fix your mistakes."
-            return ToolMessage(
-                content=str_output(output), name=call["name"], tool_call_id=call["id"]
-            )
+                content = f"Error: {repr(e)}\n Please fix your mistakes."
+                return ToolMessage(content, name=call["name"], tool_call_id=call["id"])
 
         with get_executor_for_config(config) as executor:
             outputs = [*executor.map(run_one, message.tool_calls)]
@@ -112,16 +101,13 @@ class ToolNode(RunnableCallable):
 
         async def run_one(call: ToolCall):
             try:
-                output = await self.tools_by_name[call["name"]].ainvoke(
-                    call["args"], config
-                )
+                input = {**call, **{"type": "tool_call"}}
+                return await self.tools_by_name[call["name"]].ainvoke(input, config)
             except Exception as e:
                 if not self.handle_tool_errors:
                     raise e
-                output = f"Error: {repr(e)}\n Please fix your mistakes."
-            return ToolMessage(
-                content=str_output(output), name=call["name"], tool_call_id=call["id"]
-            )
+                content = f"Error: {repr(e)}\n Please fix your mistakes."
+                return ToolMessage(content, name=call["name"], tool_call_id=call["id"])
 
         outputs = await asyncio.gather(*(run_one(call) for call in message.tool_calls))
         if output_type == "list":

libs/langgraph/poetry.lock

@@ -1746,13 +1746,13 @@ langchain-core = ">=0.2.2rc1,<0.3"
 
 [[package]]
 name = "langchain-core"
-version = "0.2.16"
+version = "0.2.19"
 description = "Building applications with LLMs through composability"
 optional = false
 python-versions = "<4.0,>=3.8.1"
 files = [
-    {file = "langchain_core-0.2.16-py3-none-any.whl", hash = "sha256:68dd6fbdd8d704e124ee14c39d0b0dcf38a47bb32234328b63ad2e98385b1c80"},
-    {file = "langchain_core-0.2.16.tar.gz", hash = "sha256:cc03083e059bff86ca3e6ba60097f91d7765a929edd04eb226bb20c208447caf"},
+    {file = "langchain_core-0.2.19-py3-none-any.whl", hash = "sha256:5b3cd34395be274c89e822c84f0e03c4da14168c177a83921c5b9414ac7a0651"},
+    {file = "langchain_core-0.2.19.tar.gz", hash = "sha256:13043a83e5c9ab58b9f5ce2a56896e7e88b752e8891b2958960a98e71801471e"},
 ]
 
 [package.dependencies]
@@ -4130,4 +4130,4 @@ test = ["big-O", "importlib-resources", "jaraco.functools", "jaraco.itertools",
 [metadata]
 lock-version = "2.0"
 python-versions = ">=3.9.0,<4.0"
-content-hash = "19250230952cb11ee6b5c820ae0a2b589ce520a59e0723204dcee0c46c3b739e"
+content-hash = "170eaa0e542a02d5f2fb0d42d1f04c5d010bd3735a44b927b28e6b742c689eb0"

libs/langgraph/pyproject.toml

@@ -9,7 +9,7 @@ repository = "https://www.github.com/langchain-ai/langgraph"
 
 [tool.poetry.dependencies]
 python = ">=3.9.0,<4.0"
-langchain-core = ">=0.2.15,<0.3"
+langchain-core = ">=0.2.19,<0.3"
 
 
 [tool.poetry.group.dev.dependencies]
@@ -61,7 +61,7 @@ omit = ["tests/*"]
 [tool.pytest-watcher]
 now = true
 delay = 0.1
-runner_args = ["-x", "--ff", "-vv", "--snapshot-update"]
+runner_args = ["--ff", "-vv", "--snapshot-update"]
 patterns = ["*.py"]
 
 [build-system]

libs/langgraph/tests/test_pregel.py

@@ -3143,6 +3143,7 @@ Some examples of past conversations:
                         "name": "search_api",
                         "args": {"query": "query"},
                         "id": "tool_call123",
+                        "type": "tool_call",
                     }
                 ],
             ),
@@ -3154,7 +3155,7 @@ Some examples of past conversations:
             ),
             AIMessage(content="answer", id=AnyStr()),
         ]
-        assert app.invoke(
+        actual = app.invoke(
             {"messages": "what is weather in sf"},
             {
                 "configurable": {
@@ -3162,7 +3163,9 @@ Some examples of past conversations:
                     "expected_examples": [],
                 },
             },
-        ) == {"messages": first_messages}
+        )
+        expected = {"messages": first_messages}
+        assert actual == expected
 
         # get first checkpoint
         chkpnt_tuple_1 = saver.get_tuple({"configurable": {"thread_id": "1"}})
@@ -3193,6 +3196,7 @@ Some examples of past conversations:
                         "name": "search_api",
                         "args": {"query": "query"},
                         "id": "tool_call123",
+                        "type": "tool_call",
                     }
                 ],
             ),
@@ -3252,6 +3256,7 @@ Some examples of past conversations:
                             "name": "search_api",
                             "args": {"query": "query"},
                             "id": "tool_call123",
+                            "type": "tool_call",
                         }
                     ],
                 ),