core: `ToolMessage.status` is not preserved by `core.messages.utils.convert_to_messages`

[Drew-Wagner]

Checked other resources

• This is a bug, not a usage question. For questions, please use the LangChain Forum (https://forum.langchain.com/).
• 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).
• 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

We expect that convert_to_messages should reverse the model_dump operation on a ToolMessage:

from langchain_core.messages import convert_to_messages, ToolMessage

tool_message = ToolMessage(content="Error: please fix your mistakes", tool_call_id="foobar", status="error")
tool_message_json = tool_message.model_dump()
tool_message_recovered = convert_to_messages([tool_message_json])[0]

# AssertionError: received "success", expected "error"
assert tool_message.status == tool_message_recovered.status, 'received "%s", expected "%s"' % (tool_message_recovered.status, tool_message.status)

Error Message and Stack Trace (if applicable)

No response

Description

• I'm storing langchain messages as JSONB in a postgres database, using message.model_dump()
• I expect that convert_to_messages should recover the original message
• Instead, the ToolMessage.status receives the default value of "success" rather than the value in the database.

System Info

System Information

OS: Linux
OS Version: #1 SMP PREEMPT_DYNAMIC Sun Mar 30 16:01:29 UTC 2025
Python Version: 3.12.11 (main, Jun 4 2025, 08:56:18) [GCC 11.4.0]

Package Information

langchain_core: 0.3.75
langchain: 0.3.27
langsmith: 0.4.23
langchain_text_splitters: 0.3.11

Optional packages not installed

langserve

Other Dependencies

async-timeout<5.0.0,>=4.0.0;: Installed. No version info available.
httpx<1,>=0.23.0: Installed. No version info available.
jsonpatch<2.0,>=1.33: Installed. No version info available.
langchain-anthropic;: Installed. No version info available.
langchain-aws;: Installed. No version info available.
langchain-azure-ai;: Installed. No version info available.
langchain-cohere;: Installed. No version info available.
langchain-community;: Installed. No version info available.
langchain-core<1.0.0,>=0.3.72: Installed. No version info available.
langchain-core<2.0.0,>=0.3.75: 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-text-splitters<1.0.0,>=0.3.9: Installed. No version info available.
langchain-together;: Installed. No version info available.
langchain-xai;: Installed. No version info available.
langsmith-pyo3>=0.1.0rc2;: Installed. No version info available.
langsmith>=0.1.17: Installed. No version info available.
langsmith>=0.3.45: Installed. No version info available.
openai-agents>=0.0.3;: Installed. No version info available.
opentelemetry-api>=1.30.0;: Installed. No version info available.
opentelemetry-exporter-otlp-proto-http>=1.30.0;: Installed. No version info available.
opentelemetry-sdk>=1.30.0;: Installed. No version info available.
orjson>=3.9.14;: Installed. No version info available.
packaging>=23.2: Installed. No version info available.
pydantic<3,>=1: Installed. No version info available.
pydantic<3.0.0,>=2.7.4: Installed. No version info available.
pydantic>=2.7.4: Installed. No version info available.
pytest>=7.0.0;: Installed. No version info available.
PyYAML>=5.3: Installed. No version info available.
requests-toolbelt>=1.0.0: Installed. No version info available.
requests<3,>=2: Installed. No version info available.
requests>=2.0.0: Installed. No version info available.
rich>=13.9.4;: Installed. No version info available.
SQLAlchemy<3,>=1.4: Installed. No version info available.
tenacity!=8.4.0,<10.0.0,>=8.1.0: Installed. No version info available.
typing-extensions>=4.7: Installed. No version info available.
vcrpy>=7.0.0;: Installed. No version info available.
zstandard>=0.23.0: Installed. No version info available.

[keenborder786]

Use the following message_to_dict and messages_from_dict:

from langchain_core.messages import message_to_dict, messages_from_dict
from langchain import hub

from langchain_core.messages import convert_to_messages, ToolMessage

tool_message = ToolMessage(content="Error: please fix your mistakes", tool_call_id="foobar", status="error")
tool_message_json = message_to_dict(tool_message)
tool_message_recovered = messages_from_dict([tool_message_json])[0]

# AssertionError: received "success", expected "error"
assert tool_message.status == tool_message_recovered.status, 'received "%s", expected "%s"' % (tool_message_recovered.status, tool_message.status)

[rishu685]

The Probable Fix
The fix would likely involve a modification to the convert_to_messages function in the LangChain library. This function needs to be updated to explicitly look for and use the status field from the input dictionary when creating a ToolMessage.

Here is a conceptual example of how the code might be adjusted.

Current (simplified) logic might look something like this:

Python

def convert_to_messages(messages_data: list[dict]) -> list:
# ... other message type handling
for message_data in messages_data:
if message_data.get("type") == "tool":
# The 'status' field is likely not being passed here
return ToolMessage(
content=message_data.get("content"),
tool_call_id=message_data.get("tool_call_id")
)
# ...
The corrected logic should be:

Python

def convert_to_messages(messages_data: list[dict]) -> list:
# ... other message type handling
for message_data in messages_data:
if message_data.get("type") == "tool":
return ToolMessage(
content=message_data.get("content"),
tool_call_id=message_data.get("tool_call_id"),
# Explicitly pass the 'status' field if it exists
status=message_data.get("status", "success")
)
# ...
By explicitly passing message_data.get("status", "success") to the ToolMessage constructor, the status from the original message will be preserve