Checked other resources

• This is a bug, not a usage question.
• I added a clear and descriptive title that summarizes this issue.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangChain rather than my code.
• The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).
• This is not related to the langchain-community package.
• I read what a minimal reproducible example is (https://stackoverflow.com/help/minimal-reproducible-example).
• I posted a self-contained, minimal, reproducible example. A maintainer can copy it and run it AS IS.

Example Code

Failed code:

from pydantic import BaseModel
from langchain.tools import tool, ToolRuntime
class InputModel(BaseModel):
 query: str
@tool(args_schema=InputModel)
def demo_tool(query: str, runtime: ToolRuntime):
 """Demo tool that just echoes the query."""
 return f"{query=} {runtime=}"
if __name__ == "__main__":
 from langchain.tools.tool_node import ToolRuntime as TR
 runtime = TR(
 state={},
 context=None,
 config={},
 tool_call_id="1",
 store=None,
 stream_writer=None,
 )
 print(demo_tool.invoke({"query": "hello", "runtime": runtime}))

Success:

from langchain.tools import tool, ToolRuntime
from pydantic import Field
from typing import Annotated
@tool
def demo_tool(
 query: Annotated[str, Field(description="The query to process")],
 runtime: ToolRuntime,
):
 """Demo tool that just echoes the query."""
 return f"{query=} {runtime=}"
if __name__ == "__main__":
 from langchain.tools.tool_node import ToolRuntime as TR
 runtime = TR(
 state={},
 context=None,
 config={},
 tool_call_id="1",
 store=None,
 stream_writer=None,
 )
 print(demo_tool.invoke({"query": "hello", "runtime": runtime}))

Error Message and Stack Trace (if applicable)

Traceback (most recent call last):
File "/Users/leopham/Documents/sapia/tia/fail.py", line 26, in
print(demo_tool.invoke({"query": "hello", "runtime": runtime}))
~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/leopham/Documents/sapia/tia/.venv/lib/python3.13/site-packages/langchain_core/tools/base.py", line 591, in invoke
return self.run(tool_input, **kwargs)
~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
File "/Users/leopham/Documents/sapia/tia/.venv/lib/python3.13/site-packages/langchain_core/tools/base.py", line 856, in run
raise error_to_raise
File "/Users/leopham/Documents/sapia/tia/.venv/lib/python3.13/site-packages/langchain_core/tools/base.py", line 825, in run
response = context.run(self._run, *tool_args, **tool_kwargs)
File "/Users/leopham/Documents/sapia/tia/.venv/lib/python3.13/site-packages/langchain_core/tools/structured.py", line 90, in _run
return self.func(*args, **kwargs)
~~~~~~~~~^^^^^^^^^^^^^^^^^
TypeError: demo_tool() missing 1 required positional argument: 'runtime'

Description

I am trying to set up the args_schema to tool function with Pydantic BaseModel

System Info

sys_info.print_sys_info()

633;Bsys_info.print_sys_info()

System Information

OS: Darwin
OS Version: Darwin Kernel Version 24.6.0: Mon Aug 11 21:16:34 PDT 2025; root:xnu-11417.140.69.701.11~1/RELEASE_ARM64_T6020
Python Version: 3.13.1 (main, Dec 3 2024, 17:59:52) [Clang 16.0.0 (clang-1600026.4)]

Package Information

langchain_core: 1.0.0
langchain: 1.0.0
langchain_community: 1.0.0a1
langsmith: 0.4.37
langchain_aws: 1.0.0
langchain_classic: 1.0.0
langchain_text_splitters: 1.0.0
langgraph_sdk: 0.2.9

Optional packages not installed

langserve

Other Dependencies

aiohttp: 3.13.1
async-timeout: Installed. No version info available.
beautifulsoup4: Installed. No version info available.
bedrock-agentcore: Installed. No version info available.
boto3: 1.40.19
claude-agent-sdk: Installed. No version info available.
dataclasses-json: 0.6.7
httpx: 0.27.0
httpx-sse: 0.4.3
jsonpatch: 1.33
langchain-anthropic: Installed. No version info available.
langchain-deepseek: Installed. No version info available.
langchain-fireworks: Installed. No version info available.
langchain-google-genai: Installed. No version info available.
langchain-google-vertexai: Installed. No version info available.
langchain-groq: Installed. No version info available.
langchain-huggingface: Installed. No version info available.
langchain-mistralai: Installed. No version info available.
langchain-ollama: Installed. No version info available.
langchain-openai: Installed. No version info available.
langchain-perplexity: Installed. No version info available.
langchain-together: Installed. No version info available.
langchain-xai: Installed. No version info available.
langgraph: 1.0.0
langsmith-pyo3: Installed. No version info available.
numpy: 2.3.4
openai-agents: Installed. No version info available.
opentelemetry-api: 1.38.0
opentelemetry-exporter-otlp-proto-http: 1.38.0
opentelemetry-sdk: 1.38.0
orjson: 3.11.3
packaging: 25.0
playwright: Installed. No version info available.
pydantic: 2.10.6
pydantic-settings: 2.10.1
pytest: 8.4.2
pyyaml: 6.0.3
PyYAML: 6.0.3
requests: 2.32.5
requests-toolbelt: 1.0.0
rich: Installed. No version info available.
sqlalchemy: 2.0.44
SQLAlchemy: 2.0.44
tenacity: 9.1.2
typing-extensions: 4.15.0
vcrpy: Installed. No version info available.
zstandard: 0.25.0