Description:
Added the content= keyword when creating SystemMessage and HumanMessage
in the messages list, making it consistent with the API reference.
### Summary
This PR updates the sentence on the "How-to guides" landing page to
replace smart (curly) quotes with straight quotes in the phrase:
> "How do I...?"
### Why This Change?
- Ensures formatting consistency across documentation
- Avoids encoding or rendering issues with smart quotes
- Matches standard Markdown and inline code formatting
This is a small change, but improves clarity and polish on a key landing
page.
Change "Linkedin" to "LinkedIn" to be consistent with LinkedIn's
spelling.
Thank you for contributing to LangChain! Follow these steps to mark your
pull request as ready for review. **If any of these steps are not
completed, your PR will not be considered for review.**
- [x] **Add tests and docs**: If you're adding a new integration, you
must include:
1. A test for the integration, preferably unit tests that do not rely on
network access,
2. An example notebook showing its use. It lives in
`docs/docs/integrations` directory.
- [x] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. **We will not consider
a PR unless these three are passing in CI.** See [contribution
guidelines](https://python.langchain.com/docs/contributing/) for more.
Additional guidelines:
- Make sure optional dependencies are imported within a function.
- Please do not add dependencies to `pyproject.toml` files (even
optional ones) unless they are **required** for unit tests.
- Most PRs should not touch more than one package.
- Changes should be backwards compatible.
Adding `create_react_agent` and introducing `langchain.agents`!
## Enhanced Structured Output
`create_react_agent` supports coercion of outputs to structured data
types like `pydantic` models, dataclasses, typed dicts, or JSON schemas
specifications.
### Structural Changes
In langgraph < 1.0, `create_react_agent` implemented support for
structured output via an additional LLM call to the model after the
standard model / tool calling loop finished. This introduced extra
expense and was unnecessary.
This new version implements structured output support in the main loop,
allowing a model to choose between calling tools or generating
structured output (or both).
The same basic pattern for structured output generation works:
```py
from langchain.agents import create_react_agent
from langchain_core.messages import HumanMessage
from pydantic import BaseModel
class Weather(BaseModel):
temperature: float
condition: str
def weather_tool(city: str) -> str:
"""Get the weather for a city."""
return f"it's sunny and 70 degrees in {city}"
agent = create_react_agent("openai:gpt-4o-mini", tools=[weather_tool], response_format=Weather)
print(repr(result["structured_response"]))
#> Weather(temperature=70.0, condition='sunny')
```
### Advanced Configuration
The new API exposes two ways to configure how structured output is
generated. Under the hood, LangChain will attempt to pick the best
approach if not explicitly specified. That is, if provider native
support is available for a given model, that takes priority over
artificial tool calling.
1. Artificial tool calling (the default for most models)
LangChain generates a tool (or tools) under the hood that match the
schema of your response format. When the model calls those tools,
LangChain coerces the args to the desired format. Note, LangChain does
not validate outputs adhering to JSON schema specifications.
<details>
<summary>Extended example</summary>
```py
from langchain.agents import create_react_agent
from langchain_core.messages import HumanMessage
from langchain.agents.structured_output import ToolStrategy
from pydantic import BaseModel
class Weather(BaseModel):
temperature: float
condition: str
def weather_tool(city: str) -> str:
"""Get the weather for a city."""
return f"it's sunny and 70 degrees in {city}"
agent = create_react_agent(
"openai:gpt-4o-mini",
tools=[weather_tool],
response_format=ToolStrategy(
schema=Weather, tool_message_content="Final Weather result generated"
),
)
result = agent.invoke({"messages": [HumanMessage("What's the weather in Tokyo?")]})
for message in result["messages"]:
message.pretty_print()
"""
================================ Human Message =================================
What's the weather in Tokyo?
================================== Ai Message ==================================
Tool Calls:
weather_tool (call_Gg933BMHMwck50Q39dtBjXm7)
Call ID: call_Gg933BMHMwck50Q39dtBjXm7
Args:
city: Tokyo
================================= Tool Message =================================
Name: weather_tool
it's sunny and 70 degrees in Tokyo
================================== Ai Message ==================================
Tool Calls:
Weather (call_9xOkYUM7PuEXl9DQq9sWGv5l)
Call ID: call_9xOkYUM7PuEXl9DQq9sWGv5l
Args:
temperature: 70
condition: sunny
================================= Tool Message =================================
Name: Weather
Final Weather result generated
"""
print(repr(result["structured_response"]))
#> Weather(temperature=70.0, condition='sunny')
```
</details>
2. Provider implementations (limited to OpenAI, Groq)
Some providers support structured output generating directly. For those
cases, we offer the `ProviderStrategy` hint:
<details>
<summary>Extended example</summary>
```py
from langchain.agents import create_react_agent
from langchain_core.messages import HumanMessage
from langchain.agents.structured_output import ProviderStrategy
from pydantic import BaseModel
class Weather(BaseModel):
temperature: float
condition: str
def weather_tool(city: str) -> str:
"""Get the weather for a city."""
return f"it's sunny and 70 degrees in {city}"
agent = create_react_agent(
"openai:gpt-4o-mini",
tools=[weather_tool],
response_format=ProviderStrategy(Weather),
)
result = agent.invoke({"messages": [HumanMessage("What's the weather in Tokyo?")]})
for message in result["messages"]:
message.pretty_print()
"""
================================ Human Message =================================
What's the weather in Tokyo?
================================== Ai Message ==================================
Tool Calls:
weather_tool (call_OFJq1FngIXS6cvjWv5nfSFZp)
Call ID: call_OFJq1FngIXS6cvjWv5nfSFZp
Args:
city: Tokyo
================================= Tool Message =================================
Name: weather_tool
it's sunny and 70 degrees in Tokyo
================================== Ai Message ==================================
{"temperature":70,"condition":"sunny"}
Weather(temperature=70.0, condition='sunny')
"""
print(repr(result["structured_response"]))
#> Weather(temperature=70.0, condition='sunny')
```
Note! The final tool message has the custom content provided by the dev.
</details>
Prompted output was previously supported and is no longer supported via
the `response_format` argument to `create_react_agent`. If there's
significant demand for this, we'd be happy to engineer a solution.
## Error Handling
`create_react_agent` now exposes an API for managing errors associated
with structured output generation. There are two common problems with
structured output generation (w/ artificial tool calling):
1. **Parsing error** -- the model generates data that doesn't match the
desired structure for the output
2. **Multiple tool calls error** -- the model generates 2 or more tool
calls associated with structured output schemas
A developer can control the desired behavior for this via the
`handle_errors` arg to `ToolStrategy`.
<details>
<summary>Extended example</summary>
```py
from langchain_core.messages import HumanMessage
from pydantic import BaseModel
from langchain.agents import create_react_agent
from langchain.agents.structured_output import StructuredOutputValidationError, ToolStrategy
class Weather(BaseModel):
temperature: float
condition: str
def weather_tool(city: str) -> str:
"""Get the weather for a city."""
return f"it's sunny and 70 degrees in {city}"
def handle_validation_error(error: Exception) -> str:
if isinstance(error, StructuredOutputValidationError):
return (
f"Please call the {error.tool_name} call again with the correct arguments. "
f"Your mistake was: {error.source}"
)
raise error
agent = create_react_agent(
"openai:gpt-5",
tools=[weather_tool],
response_format=ToolStrategy(
schema=Weather,
handle_errors=handle_validation_error,
),
)
```
</details>
## Error Handling for Tool Calling
Tools fail for two main reasons:
1. **Invocation failure** -- the args generated by the model for the
tool are incorrect (missing, incompatible data types, etc)
2. **Execution failure** -- the tool execution itself fails due to a
developer error, network error, or some other exception.
By default, when tool **invocation** fails, the react agent will return
an artificial `ToolMessage` to the model asking it to correct its
mistakes and retry.
Now, when tool **execution** fails, the react agent raises the
`ToolException` by default instead of asking the model to retry. This
helps to avoid looping that should be avoided due to the aforementioned
issues.
Developers can configure their desired behavior for retries / error
handling via the `handle_tool_errors` arg to `ToolNode`.
## Pre-Bound Models
`create_react_agent` no longer supports inputs to `model` that have been
pre-bound w/ tools or other configuration. To properly support
structured output generation, the agent itself needs the power to bind
tools + structured output kwargs.
This also makes the devx cleaner - it's always expected that `model` is
an instance of `BaseChatModel` (or `str` that we coerce into a chat
model instance).
Dynamic model functions can return a pre-bound model **IF** structured
output is not also used. Dynamic model functions can then bind tools /
structured output logic.
## Import Changes
Users should now use `create_react_agent` from `langchain.agents`
instead of `langgraph.prebuilts`.
Other imports have a similar migration path, `ToolNode` and `AgentState`
for example.
* `chat_agent_executor.py` -> `react_agent.py`
Some notes:
1. Disabled blockbuster + some linting in `langchain/agents` -- beyond
ideal, but necessary to get this across the line for the alpha. We
should re-enable before official release.
- **Description:** Updated Docker command to use ClickHouse 25.7 (has
`vector_similarity` index support). Added `CLICKHOUSE_SKIP_USER_SETUP=1`
env param to [bypass default user
setup](https://clickhouse.com/docs/install/docker#managing-default-user)
and allow external network access. There was also a bug where if you try
to access results using `similarity_search_with_relevance_scores`, they
need to unpacked first.
- **Issue:** Fixes#32094 if someone following tutorial with default
Clickhouse configurations.
# Description
Updated documentation to reflect Microsoft’s rebranding of Azure AI
Studio to Azure AI Foundry. This ensures consistency with current Azure
terminology across the docs.
# Issue
N/A
# Dependencies
None
The async version of the test should use the `ayield_keys` method
instead of `yield_keys`.
Otherwise tools such as `blockbuster` may trigger on a blocking call.
**Description:**
Fixed corrupted text in the code cell output of the documentation
notebook. The code cell itself was correct, but the saved output
contained garbage text.
**Issue:**
The saved output in the documentation notebook contained garbage/typo
text in the table name.
**Dependencies:**
None
Having vercel attempt to deploy on each commit (even if unrelated to
docs) was getting annoying. Options:
- `[skip-preview]`
- `[no-preview]`
- `[skip-deploy]`
Full example: `fix(core): resolve memory leak [no-preview]`
* Create usage metadata on
[`message_delta`](https://docs.anthropic.com/en/docs/build-with-claude/streaming#event-types)
instead of at the beginning. Consequently, token counts are not included
during streaming but instead at the end. This allows for accurate
reporting of server-side tool usage (important for billing)
* Add some clarifying comments
* Fix some outstanding Pylance warnings
* Remove unnecessary `text` popping in thinking blocks
* Also now correctly reports `input_cache_read`/`input_cache_creation`
as a result
When citations are returned from streaming, they include a `file_id:
null` field in their `content_block_location` structure.
When these citations are passed back to the API in subsequent messages,
the API rejects them with "Extra inputs are not permitted" for the
`file_id` field.
**Description:**
Corrected LangGraph documentation link (changed to “guides”), and added
a link to LangGraph JS how-to guides for clarity.
**Issue:**
N/A
**Dependencies:**
None
---------
Co-authored-by: Mason Daugherty <mason@langchain.dev>
The appropriate `ToolNode` attribute for error handling is called
`handle_tool_errors` instead of `handle_tool_error`.
For further info see [ToolNode source code in
LangGraph](https://github.com/langchain-ai/langgraph/blob/main/libs/prebuilt/langgraph/prebuilt/tool_node.py#L255)
**Twitter handle:** gitaroktato
- [x] **Add tests and docs**: If you're adding a new integration, you
must include:
1. A test for the integration, preferably unit tests that do not rely on
network access,
2. An example notebook showing its use. It lives in
`docs/docs/integrations` directory.
- [x] **Lint and test**: Run `make format`, `make lint` and `make test`
from the root of the package(s) you've modified. **We will not consider
a PR unless these three are passing in CI.** See [contribution
guidelines](https://python.langchain.com/docs/contributing/) for more.
Additional guidelines:
- Make sure optional dependencies are imported within a function.
- Please do not add dependencies to `pyproject.toml` files (even
optional ones) unless they are **required** for unit tests.
- Most PRs should not touch more than one package.
- Changes should be backwards compatible.
