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AzureChatOpenAI

Reference docs

This page contains reference documentation for AzureChatOpenAI. See the docs for conceptual guides, tutorials, and examples on using AzureChatOpenAI.

langchain_openai.chat_models.AzureChatOpenAI

Bases: BaseChatOpenAI

Azure OpenAI chat model integration.

Setup

Head to the Azure OpenAI quickstart guide to create your Azure OpenAI deployment.

Then install langchain-openai and set environment variables AZURE_OPENAI_API_KEY and AZURE_OPENAI_ENDPOINT:

pip install -U langchain-openai

export AZURE_OPENAI_API_KEY="your-api-key"
export AZURE_OPENAI_ENDPOINT="https://your-endpoint.openai.azure.com/"

Key init args — completion params: azure_deployment: Name of Azure OpenAI deployment to use. temperature: Sampling temperature. max_tokens: Max number of tokens to generate. logprobs: Whether to return logprobs.

Key init args — client params: api_version: Azure OpenAI REST API version to use (distinct from the version of the underlying model). See more on the different versions. timeout: Timeout for requests. max_retries: Max number of retries. organization: OpenAI organization ID. If not passed in will be read from env var OPENAI_ORG_ID. model: The name of the underlying OpenAI model. Used for tracing and token counting. Does not affect completion. E.g. 'gpt-4', 'gpt-35-turbo', etc. model_version: The version of the underlying OpenAI model. Used for tracing and token counting. Does not affect completion. E.g., '0125', '0125-preview', etc.

See full list of supported init args and their descriptions in the params section.

Instantiate
from langchain_openai import AzureChatOpenAI

model = AzureChatOpenAI(
    azure_deployment="your-deployment",
    api_version="2024-05-01-preview",
    temperature=0,
    max_tokens=None,
    timeout=None,
    max_retries=2,
    # organization="...",
    # model="gpt-35-turbo",
    # model_version="0125",
    # other params...
)

Note

Any param which is not explicitly supported will be passed directly to the openai.AzureOpenAI.chat.completions.create(...) API every time to the model is invoked.

For example:

from langchain_openai import AzureChatOpenAI
import openai

AzureChatOpenAI(..., logprobs=True).invoke(...)

# results in underlying API call of:

openai.AzureOpenAI(..).chat.completions.create(..., logprobs=True)

# which is also equivalent to:

AzureChatOpenAI(...).invoke(..., logprobs=True)
Invoke
messages = [
    (
        "system",
        "You are a helpful translator. Translate the user sentence to French.",
    ),
    ("human", "I love programming."),
]
model.invoke(messages)
AIMessage(
    content="J'adore programmer.",
    usage_metadata={
        "input_tokens": 28,
        "output_tokens": 6,
        "total_tokens": 34,
    },
    response_metadata={
        "token_usage": {
            "completion_tokens": 6,
            "prompt_tokens": 28,
            "total_tokens": 34,
        },
        "model_name": "gpt-4",
        "system_fingerprint": "fp_7ec89fabc6",
        "prompt_filter_results": [
            {
                "prompt_index": 0,
                "content_filter_results": {
                    "hate": {"filtered": False, "severity": "safe"},
                    "self_harm": {"filtered": False, "severity": "safe"},
                    "sexual": {"filtered": False, "severity": "safe"},
                    "violence": {"filtered": False, "severity": "safe"},
                },
            }
        ],
        "finish_reason": "stop",
        "logprobs": None,
        "content_filter_results": {
            "hate": {"filtered": False, "severity": "safe"},
            "self_harm": {"filtered": False, "severity": "safe"},
            "sexual": {"filtered": False, "severity": "safe"},
            "violence": {"filtered": False, "severity": "safe"},
        },
    },
    id="run-6d7a5282-0de0-4f27-9cc0-82a9db9a3ce9-0",
)
Stream
for chunk in model.stream(messages):
    print(chunk.text, end="")
AIMessageChunk(content="", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(content="J", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(content="'", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(content="ad", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(content="ore", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(content=" la", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(
    content=" programm", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f"
)
AIMessageChunk(content="ation", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(content=".", id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f")
AIMessageChunk(
    content="",
    response_metadata={
        "finish_reason": "stop",
        "model_name": "gpt-4",
        "system_fingerprint": "fp_811936bd4f",
    },
    id="run-a6f294d3-0700-4f6a-abc2-c6ef1178c37f",
)
stream = model.stream(messages)
full = next(stream)
for chunk in stream:
    full += chunk
full
AIMessageChunk(
    content="J'adore la programmation.",
    response_metadata={
        "finish_reason": "stop",
        "model_name": "gpt-4",
        "system_fingerprint": "fp_811936bd4f",
    },
    id="run-ba60e41c-9258-44b8-8f3a-2f10599643b3",
)
Async
await model.ainvoke(messages)

# stream:
# async for chunk in (await model.astream(messages))

# batch:
# await model.abatch([messages])
Tool calling
from pydantic import BaseModel, Field


class GetWeather(BaseModel):
    '''Get the current weather in a given location'''

    location: str = Field(
        ..., description="The city and state, e.g. San Francisco, CA"
    )


class GetPopulation(BaseModel):
    '''Get the current population in a given location'''

    location: str = Field(
        ..., description="The city and state, e.g. San Francisco, CA"
    )


model_with_tools = model.bind_tools([GetWeather, GetPopulation])
ai_msg = model_with_tools.invoke(
    "Which city is hotter today and which is bigger: LA or NY?"
)
ai_msg.tool_calls
[
    {
        "name": "GetWeather",
        "args": {"location": "Los Angeles, CA"},
        "id": "call_6XswGD5Pqk8Tt5atYr7tfenU",
    },
    {
        "name": "GetWeather",
        "args": {"location": "New York, NY"},
        "id": "call_ZVL15vA8Y7kXqOy3dtmQgeCi",
    },
    {
        "name": "GetPopulation",
        "args": {"location": "Los Angeles, CA"},
        "id": "call_49CFW8zqC9W7mh7hbMLSIrXw",
    },
    {
        "name": "GetPopulation",
        "args": {"location": "New York, NY"},
        "id": "call_6ghfKxV264jEfe1mRIkS3PE7",
    },
]
Structured output
from typing import Optional

from pydantic import BaseModel, Field


class Joke(BaseModel):
    '''Joke to tell user.'''

    setup: str = Field(description="The setup of the joke")
    punchline: str = Field(description="The punchline to the joke")
    rating: int | None = Field(
        description="How funny the joke is, from 1 to 10"
    )


structured_model = model.with_structured_output(Joke)
structured_model.invoke("Tell me a joke about cats")
Joke(
    setup="Why was the cat sitting on the computer?",
    punchline="To keep an eye on the mouse!",
    rating=None,
)

See AzureChatOpenAI.with_structured_output() for more.

JSON mode
json_model = model.bind(response_format={"type": "json_object"})
ai_msg = json_model.invoke(
    "Return a JSON object with key 'random_ints' and a value of 10 random ints in [0-99]"
)
ai_msg.content
'\\n{\\n  "random_ints": [23, 87, 45, 12, 78, 34, 56, 90, 11, 67]\\n}'
Image input
import base64
import httpx
from langchain_core.messages import HumanMessage

image_url = "https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Gfp-wisconsin-madison-the-nature-boardwalk.jpg/2560px-Gfp-wisconsin-madison-the-nature-boardwalk.jpg"
image_data = base64.b64encode(httpx.get(image_url).content).decode("utf-8")
message = HumanMessage(
    content=[
        {"type": "text", "text": "describe the weather in this image"},
        {
            "type": "image_url",
            "image_url": {"url": f"data:image/jpeg;base64,{image_data}"},
        },
    ]
)
ai_msg = model.invoke([message])
ai_msg.content
"The weather in the image appears to be quite pleasant. The sky is mostly clear"
Token usage
ai_msg = model.invoke(messages)
ai_msg.usage_metadata
{"input_tokens": 28, "output_tokens": 5, "total_tokens": 33}

Logprobs:

logprobs_model = model.bind(logprobs=True)
ai_msg = logprobs_model.invoke(messages)
ai_msg.response_metadata["logprobs"]

```python
{
    "content": [
        {
            "token": "J",
            "bytes": [74],
            "logprob": -4.9617593e-06,
            "top_logprobs": [],
        },
        {
            "token": "'adore",
            "bytes": [39, 97, 100, 111, 114, 101],
            "logprob": -0.25202933,
            "top_logprobs": [],
        },
        {
            "token": " la",
            "bytes": [32, 108, 97],
            "logprob": -0.20141791,
            "top_logprobs": [],
        },
        {
            "token": " programmation",
            "bytes": [
                32,
                112,
                114,
                111,
                103,
                114,
                97,
                109,
                109,
                97,
                116,
                105,
                111,
                110,
            ],
            "logprob": -1.9361265e-07,
            "top_logprobs": [],
        },
        {
            "token": ".",
            "bytes": [46],
            "logprob": -1.2233183e-05,
            "top_logprobs": [],
        },
    ]
}
```

Response metadata

ai_msg = model.invoke(messages)
ai_msg.response_metadata

```python
{
    "token_usage": {
        "completion_tokens": 6,
        "prompt_tokens": 28,
        "total_tokens": 34,
    },
    "model_name": "gpt-35-turbo",
    "system_fingerprint": None,
    "prompt_filter_results": [
        {
            "prompt_index": 0,
            "content_filter_results": {
                "hate": {"filtered": False, "severity": "safe"},
                "self_harm": {"filtered": False, "severity": "safe"},
                "sexual": {"filtered": False, "severity": "safe"},
                "violence": {"filtered": False, "severity": "safe"},
            },
        }
    ],
    "finish_reason": "stop",
    "logprobs": None,
    "content_filter_results": {
        "hate": {"filtered": False, "severity": "safe"},
        "self_harm": {"filtered": False, "severity": "safe"},
        "sexual": {"filtered": False, "severity": "safe"},
        "violence": {"filtered": False, "severity": "safe"},
    },
}
```
METHOD DESCRIPTION
get_name

Get the name of the Runnable.

get_input_schema

Get a Pydantic model that can be used to validate input to the Runnable.

get_input_jsonschema

Get a JSON schema that represents the input to the Runnable.

get_output_schema

Get a Pydantic model that can be used to validate output to the Runnable.

get_output_jsonschema

Get a JSON schema that represents the output of the Runnable.

config_schema

The type of config this Runnable accepts specified as a Pydantic model.

get_config_jsonschema

Get a JSON schema that represents the config of the Runnable.

get_graph

Return a graph representation of this Runnable.

get_prompts

Return a list of prompts used by this Runnable.

__or__

Runnable "or" operator.

__ror__

Runnable "reverse-or" operator.

pipe

Pipe Runnable objects.

pick

Pick keys from the output dict of this Runnable.

assign

Assigns new fields to the dict output of this Runnable.

invoke

Transform a single input into an output.

ainvoke

Transform a single input into an output.

batch

Default implementation runs invoke in parallel using a thread pool executor.

batch_as_completed

Run invoke in parallel on a list of inputs.

abatch

Default implementation runs ainvoke in parallel using asyncio.gather.

abatch_as_completed

Run ainvoke in parallel on a list of inputs.

stream

Default implementation of stream, which calls invoke.

astream

Default implementation of astream, which calls ainvoke.

astream_log

Stream all output from a Runnable, as reported to the callback system.

astream_events

Generate a stream of events.

transform

Transform inputs to outputs.

atransform

Transform inputs to outputs.

bind

Bind arguments to a Runnable, returning a new Runnable.

with_config

Bind config to a Runnable, returning a new Runnable.

with_listeners

Bind lifecycle listeners to a Runnable, returning a new Runnable.

with_alisteners

Bind async lifecycle listeners to a Runnable.

with_types

Bind input and output types to a Runnable, returning a new Runnable.

with_retry

Create a new Runnable that retries the original Runnable on exceptions.

map

Return a new Runnable that maps a list of inputs to a list of outputs.

with_fallbacks

Add fallbacks to a Runnable, returning a new Runnable.

as_tool

Create a BaseTool from a Runnable.

__init__
lc_id

Return a unique identifier for this class for serialization purposes.

to_json

Serialize the Runnable to JSON.

to_json_not_implemented

Serialize a "not implemented" object.

configurable_fields

Configure particular Runnable fields at runtime.

configurable_alternatives

Configure alternatives for Runnable objects that can be set at runtime.

set_verbose

If verbose is None, set it.

generate_prompt

Pass a sequence of prompts to the model and return model generations.

agenerate_prompt

Asynchronously pass a sequence of prompts and return model generations.

get_token_ids

Get the tokens present in the text with tiktoken package.

get_num_tokens

Get the number of tokens present in the text.

get_num_tokens_from_messages

Calculate num tokens for gpt-3.5-turbo and gpt-4 with tiktoken package.

generate

Pass a sequence of prompts to the model and return model generations.

agenerate

Asynchronously pass a sequence of prompts to a model and return generations.

dict

Return a dictionary of the LLM.

bind_tools

Bind tool-like objects to this chat model.

build_extra

Build extra kwargs from additional params that were passed in.

validate_temperature

Validate temperature parameter for different models.

get_lc_namespace

Get the namespace of the LangChain object.

is_lc_serializable

Check if the class is serializable in langchain.

validate_environment

Validate that api key and python package exists in environment.

with_structured_output

Model wrapper that returns outputs formatted to match the given schema.

name class-attribute instance-attribute

name: str | None = None

The name of the Runnable. Used for debugging and tracing.

InputType property

InputType: TypeAlias

Get the input type for this Runnable.

OutputType property

OutputType: Any

Get the output type for this Runnable.

input_schema property

input_schema: type[BaseModel]

The type of input this Runnable accepts specified as a Pydantic model.

output_schema property

output_schema: type[BaseModel]

Output schema.

The type of output this Runnable produces specified as a Pydantic model.

config_specs property

config_specs: list[ConfigurableFieldSpec]

List configurable fields for this Runnable.

cache class-attribute instance-attribute

cache: BaseCache | bool | None = Field(default=None, exclude=True)

Whether to cache the response.

  • If True, will use the global cache.
  • If False, will not use a cache
  • If None, will use the global cache if it's set, otherwise no cache.
  • If instance of BaseCache, will use the provided cache.

Caching is not currently supported for streaming methods of models.

verbose class-attribute instance-attribute

verbose: bool = Field(default_factory=_get_verbosity, exclude=True, repr=False)

Whether to print out response text.

callbacks class-attribute instance-attribute

callbacks: Callbacks = Field(default=None, exclude=True)

Callbacks to add to the run trace.

tags class-attribute instance-attribute

tags: list[str] | None = Field(default=None, exclude=True)

Tags to add to the run trace.

metadata class-attribute instance-attribute

metadata: dict[str, Any] | None = Field(default=None, exclude=True)

Metadata to add to the run trace.

custom_get_token_ids class-attribute instance-attribute

custom_get_token_ids: Callable[[str], list[int]] | None = Field(
    default=None, exclude=True
)

Optional encoder to use for counting tokens.

rate_limiter class-attribute instance-attribute

rate_limiter: BaseRateLimiter | None = Field(default=None, exclude=True)

An optional rate limiter to use for limiting the number of requests.

disable_streaming class-attribute instance-attribute

disable_streaming: bool | Literal['tool_calling'] = False

Whether to disable streaming for this model.

If streaming is bypassed, then stream/astream/astream_events will defer to invoke/ainvoke.

  • If True, will always bypass streaming case.
  • If 'tool_calling', will bypass streaming case only when the model is called with a tools keyword argument. In other words, LangChain will automatically switch to non-streaming behavior (invoke) only when the tools argument is provided. This offers the best of both worlds.
  • If False (Default), will always use streaming case if available.

The main reason for this flag is that code might be written using stream and a user may want to swap out a given model for another model whose the implementation does not properly support streaming.

output_version class-attribute instance-attribute

output_version: str | None = Field(
    default_factory=from_env("LC_OUTPUT_VERSION", default=None)
)

Version of AIMessage output format to use.

This field is used to roll-out new output formats for chat model AIMessage responses in a backwards-compatible way.

Supported values:

  • 'v0': AIMessage format as of langchain-openai 0.3.x.
  • 'responses/v1': Formats Responses API output items into AIMessage content blocks (Responses API only)
  • 'v1': v1 of LangChain cross-provider standard.

Behavior changed in 1.0.0

Default updated to "responses/v1".

temperature class-attribute instance-attribute

temperature: float | None = None

What sampling temperature to use.

model_kwargs class-attribute instance-attribute

model_kwargs: dict[str, Any] = Field(default_factory=dict)

Holds any model parameters valid for create call not explicitly specified.

openai_api_base class-attribute instance-attribute

openai_api_base: str | None = Field(default=None, alias='base_url')

Base URL path for API requests, leave blank if not using a proxy or service emulator.

openai_organization class-attribute instance-attribute

openai_organization: str | None = Field(default=None, alias='organization')

Automatically inferred from env var OPENAI_ORG_ID if not provided.

request_timeout class-attribute instance-attribute

request_timeout: float | tuple[float, float] | Any | None = Field(
    default=None, alias="timeout"
)

Timeout for requests to OpenAI completion API. Can be float, httpx.Timeout or None.

stream_usage class-attribute instance-attribute

stream_usage: bool | None = None

Whether to include usage metadata in streaming output. If enabled, an additional message chunk will be generated during the stream including usage metadata.

This parameter is enabled unless openai_api_base is set or the model is initialized with a custom client, as many chat completions APIs do not support streaming token usage.

Added in version 0.3.9

Behavior changed in 0.3.35

Enabled for default base URL and client.

max_retries class-attribute instance-attribute

max_retries: int | None = None

Maximum number of retries to make when generating.

presence_penalty class-attribute instance-attribute

presence_penalty: float | None = None

Penalizes repeated tokens.

frequency_penalty class-attribute instance-attribute

frequency_penalty: float | None = None

Penalizes repeated tokens according to frequency.

seed class-attribute instance-attribute

seed: int | None = None

Seed for generation

logprobs class-attribute instance-attribute

logprobs: bool | None = None

Whether to return logprobs.

top_logprobs class-attribute instance-attribute

top_logprobs: int | None = None

Number of most likely tokens to return at each token position, each with an associated log probability. logprobs must be set to true if this parameter is used.

logit_bias class-attribute instance-attribute

logit_bias: dict[int, int] | None = None

Modify the likelihood of specified tokens appearing in the completion.

streaming class-attribute instance-attribute

streaming: bool = False

Whether to stream the results or not.

n class-attribute instance-attribute

n: int | None = None

Number of chat completions to generate for each prompt.

top_p class-attribute instance-attribute

top_p: float | None = None

Total probability mass of tokens to consider at each step.

reasoning_effort class-attribute instance-attribute

reasoning_effort: str | None = None

Constrains effort on reasoning for reasoning models. For use with the Chat Completions API.

Reasoning models only.

Currently supported values are 'minimal', 'low', 'medium', and 'high'. Reducing reasoning effort can result in faster responses and fewer tokens used on reasoning in a response.

reasoning class-attribute instance-attribute

reasoning: dict[str, Any] | None = None

Reasoning parameters for reasoning models. For use with the Responses API.

reasoning={
    "effort": "medium",  # Can be "low", "medium", or "high"
    "summary": "auto",  # Can be "auto", "concise", or "detailed"
}

Added in version 0.3.24

verbosity class-attribute instance-attribute

verbosity: str | None = None

Controls the verbosity level of responses for reasoning models. For use with the Responses API.

Currently supported values are 'low', 'medium', and 'high'.

Added in version 0.3.28

tiktoken_model_name class-attribute instance-attribute

tiktoken_model_name: str | None = None

The model name to pass to tiktoken when using this class. Tiktoken is used to count the number of tokens in documents to constrain them to be under a certain limit. By default, when set to None, this will be the same as the embedding model name. However, there are some cases where you may want to use this Embedding class with a model name not supported by tiktoken. This can include when using Azure embeddings or when using one of the many model providers that expose an OpenAI-like API but with different models. In those cases, in order to avoid erroring when tiktoken is called, you can specify a model name to use here.

http_client class-attribute instance-attribute

http_client: Any | None = Field(default=None, exclude=True)

Optional httpx.Client. Only used for sync invocations. Must specify http_async_client as well if you'd like a custom client for async invocations.

http_async_client class-attribute instance-attribute

http_async_client: Any | None = Field(default=None, exclude=True)

Optional httpx.AsyncClient. Only used for async invocations. Must specify http_client as well if you'd like a custom client for sync invocations.

stop class-attribute instance-attribute

stop: list[str] | str | None = Field(default=None, alias='stop_sequences')

Default stop sequences.

extra_body class-attribute instance-attribute

extra_body: Mapping[str, Any] | None = None

Optional additional JSON properties to include in the request parameters when making requests to OpenAI compatible APIs, such as vLLM, LM Studio, or other providers.

This is the recommended way to pass custom parameters that are specific to your OpenAI-compatible API provider but not part of the standard OpenAI API.

Examples:

  • LM Studio TTL parameter: extra_body={"ttl": 300}
  • vLLM custom parameters: extra_body={"use_beam_search": True}
  • Any other provider-specific parameters

Warning

Do not use model_kwargs for custom parameters that are not part of the standard OpenAI API, as this will cause errors when making API calls. Use extra_body instead.

include_response_headers class-attribute instance-attribute

include_response_headers: bool = False

Whether to include response headers in the output message response_metadata.

include class-attribute instance-attribute

include: list[str] | None = None

Additional fields to include in generations from Responses API.

Supported values:

  • 'file_search_call.results'
  • 'message.input_image.image_url'
  • 'computer_call_output.output.image_url'
  • 'reasoning.encrypted_content'
  • 'code_interpreter_call.outputs'

Added in version 0.3.24

service_tier class-attribute instance-attribute

service_tier: str | None = None

Latency tier for request. Options are 'auto', 'default', or 'flex'. Relevant for users of OpenAI's scale tier service.

store class-attribute instance-attribute

store: bool | None = None

If True, OpenAI may store response data for future use.

Defaults to True for the Responses API and False for the Chat Completions API.

Added in version 0.3.24

truncation class-attribute instance-attribute

truncation: str | None = None

Truncation strategy (Responses API). Can be 'auto' or 'disabled' (default). If 'auto', model may drop input items from the middle of the message sequence to fit the context window.

Added in version 0.3.24

use_previous_response_id class-attribute instance-attribute

use_previous_response_id: bool = False

If True, always pass previous_response_id using the ID of the most recent response. Responses API only.

Input messages up to the most recent response will be dropped from request payloads.

For example, the following two are equivalent:

model = ChatOpenAI(
    model="...",
    use_previous_response_id=True,
)
model.invoke(
    [
        HumanMessage("Hello"),
        AIMessage("Hi there!", response_metadata={"id": "resp_123"}),
        HumanMessage("How are you?"),
    ]
)
model = ChatOpenAI(model="...", use_responses_api=True)
model.invoke([HumanMessage("How are you?")], previous_response_id="resp_123")

Added in version 0.3.26

use_responses_api class-attribute instance-attribute

use_responses_api: bool | None = None

Whether to use the Responses API instead of the Chat API.

If not specified then will be inferred based on invocation params.

Added in version 0.3.9

azure_endpoint class-attribute instance-attribute

azure_endpoint: str | None = Field(
    default_factory=from_env("AZURE_OPENAI_ENDPOINT", default=None)
)

Your Azure endpoint, including the resource.

Automatically inferred from env var AZURE_OPENAI_ENDPOINT if not provided.

Example: https://example-resource.azure.openai.com/

deployment_name class-attribute instance-attribute

deployment_name: str | None = Field(default=None, alias='azure_deployment')

A model deployment.

If given sets the base client URL to include /deployments/{azure_deployment}

Note

This means you won't be able to use non-deployment endpoints.

openai_api_version class-attribute instance-attribute

openai_api_version: str | None = Field(
    alias="api_version", default_factory=from_env("OPENAI_API_VERSION", default=None)
)

Automatically inferred from env var OPENAI_API_VERSION if not provided.

openai_api_key class-attribute instance-attribute

openai_api_key: SecretStr | None = Field(
    alias="api_key",
    default_factory=secret_from_env(
        ["AZURE_OPENAI_API_KEY", "OPENAI_API_KEY"], default=None
    ),
)

Automatically inferred from env var AZURE_OPENAI_API_KEY if not provided.

azure_ad_token class-attribute instance-attribute

azure_ad_token: SecretStr | None = Field(
    default_factory=secret_from_env("AZURE_OPENAI_AD_TOKEN", default=None)
)

Your Azure Active Directory token.

Automatically inferred from env var AZURE_OPENAI_AD_TOKEN if not provided.

For more, see this page.

azure_ad_token_provider class-attribute instance-attribute

azure_ad_token_provider: Callable[[], str] | None = None

A function that returns an Azure Active Directory token.

Will be invoked on every sync request. For async requests, will be invoked if azure_ad_async_token_provider is not provided.

azure_ad_async_token_provider class-attribute instance-attribute

azure_ad_async_token_provider: Callable[[], Awaitable[str]] | None = None

A function that returns an Azure Active Directory token.

Will be invoked on every async request.

model_version class-attribute instance-attribute

model_version: str = ''

The version of the model (e.g. '0125' for 'gpt-3.5-0125').

Azure OpenAI doesn't return model version with the response by default so it must be manually specified if you want to use this information downstream, e.g. when calculating costs.

When you specify the version, it will be appended to the model name in the response. Setting correct version will help you to calculate the cost properly. Model version is not validated, so make sure you set it correctly to get the correct cost.

openai_api_type class-attribute instance-attribute

openai_api_type: str | None = Field(
    default_factory=from_env("OPENAI_API_TYPE", default="azure")
)

Legacy, for openai<1.0.0 support.

validate_base_url class-attribute instance-attribute

validate_base_url: bool = True

If legacy arg openai_api_base is passed in, try to infer if it is a base_url or azure_endpoint and update client params accordingly.

model_name class-attribute instance-attribute

model_name: str | None = Field(default=None, alias='model')

Name of the deployed OpenAI model, e.g. 'gpt-4o', 'gpt-35-turbo', etc.

Distinct from the Azure deployment name, which is set by the Azure user. Used for tracing and token counting.

Warning

Does NOT affect completion.

disabled_params class-attribute instance-attribute

disabled_params: dict[str, Any] | None = Field(default=None)

Parameters of the OpenAI client or chat.completions endpoint that should be disabled for the given model.

Should be specified as {"param": None | ['val1', 'val2']} where the key is the parameter and the value is either None, meaning that parameter should never be used, or it's a list of disabled values for the parameter.

For example, older models may not support the 'parallel_tool_calls' parameter at all, in which case disabled_params={"parallel_tool_calls: None} can ben passed in.

If a parameter is disabled then it will not be used by default in any methods, e.g. in langchain_openai.chat_models.azure.AzureChatOpenAI.with_structured_output. However this does not prevent a user from directly passed in the parameter during invocation.

By default, unless model_name="gpt-4o" is specified, then 'parallel_tools_calls' will be disabled.

max_tokens class-attribute instance-attribute

max_tokens: int | None = Field(default=None, alias='max_completion_tokens')

Maximum number of tokens to generate.

lc_secrets property

lc_secrets: dict[str, str]

Get the mapping of secret environment variables.

lc_attributes property

lc_attributes: dict[str, Any]

Get the attributes relevant to tracing.

get_name

get_name(suffix: str | None = None, *, name: str | None = None) -> str

Get the name of the Runnable.

PARAMETER DESCRIPTION
suffix

An optional suffix to append to the name.

TYPE: str | None DEFAULT: None

name

An optional name to use instead of the Runnable's name.

TYPE: str | None DEFAULT: None

RETURNS DESCRIPTION
str

The name of the Runnable.

get_input_schema

get_input_schema(config: RunnableConfig | None = None) -> type[BaseModel]

Get a Pydantic model that can be used to validate input to the Runnable.

Runnable objects that leverage the configurable_fields and configurable_alternatives methods will have a dynamic input schema that depends on which configuration the Runnable is invoked with.

This method allows to get an input schema for a specific configuration.

PARAMETER DESCRIPTION
config

A config to use when generating the schema.

TYPE: RunnableConfig | None DEFAULT: None

RETURNS DESCRIPTION
type[BaseModel]

A Pydantic model that can be used to validate input.

get_input_jsonschema

get_input_jsonschema(config: RunnableConfig | None = None) -> dict[str, Any]

Get a JSON schema that represents the input to the Runnable.

PARAMETER DESCRIPTION
config

A config to use when generating the schema.

TYPE: RunnableConfig | None DEFAULT: None

RETURNS DESCRIPTION
dict[str, Any]

A JSON schema that represents the input to the Runnable.

Example
from langchain_core.runnables import RunnableLambda


def add_one(x: int) -> int:
    return x + 1


runnable = RunnableLambda(add_one)

print(runnable.get_input_jsonschema())

Added in version 0.3.0

get_output_schema

get_output_schema(config: RunnableConfig | None = None) -> type[BaseModel]

Get a Pydantic model that can be used to validate output to the Runnable.

Runnable objects that leverage the configurable_fields and configurable_alternatives methods will have a dynamic output schema that depends on which configuration the Runnable is invoked with.

This method allows to get an output schema for a specific configuration.

PARAMETER DESCRIPTION
config

A config to use when generating the schema.

TYPE: RunnableConfig | None DEFAULT: None

RETURNS DESCRIPTION
type[BaseModel]

A Pydantic model that can be used to validate output.

get_output_jsonschema

get_output_jsonschema(config: RunnableConfig | None = None) -> dict[str, Any]

Get a JSON schema that represents the output of the Runnable.

PARAMETER DESCRIPTION
config

A config to use when generating the schema.

TYPE: RunnableConfig | None DEFAULT: None

RETURNS DESCRIPTION
dict[str, Any]

A JSON schema that represents the output of the Runnable.

Example
from langchain_core.runnables import RunnableLambda


def add_one(x: int) -> int:
    return x + 1


runnable = RunnableLambda(add_one)

print(runnable.get_output_jsonschema())

Added in version 0.3.0

config_schema

config_schema(*, include: Sequence[str] | None = None) -> type[BaseModel]

The type of config this Runnable accepts specified as a Pydantic model.

To mark a field as configurable, see the configurable_fields and configurable_alternatives methods.

PARAMETER DESCRIPTION
include

A list of fields to include in the config schema.

TYPE: Sequence[str] | None DEFAULT: None

RETURNS DESCRIPTION
type[BaseModel]

A Pydantic model that can be used to validate config.

get_config_jsonschema

get_config_jsonschema(*, include: Sequence[str] | None = None) -> dict[str, Any]

Get a JSON schema that represents the config of the Runnable.

PARAMETER DESCRIPTION
include

A list of fields to include in the config schema.

TYPE: Sequence[str] | None DEFAULT: None

RETURNS DESCRIPTION
dict[str, Any]

A JSON schema that represents the config of the Runnable.

Added in version 0.3.0

get_graph

get_graph(config: RunnableConfig | None = None) -> Graph

Return a graph representation of this Runnable.

get_prompts

get_prompts(config: RunnableConfig | None = None) -> list[BasePromptTemplate]

Return a list of prompts used by this Runnable.

__or__

__or__(
    other: Runnable[Any, Other]
    | Callable[[Iterator[Any]], Iterator[Other]]
    | Callable[[AsyncIterator[Any]], AsyncIterator[Other]]
    | Callable[[Any], Other]
    | Mapping[str, Runnable[Any, Other] | Callable[[Any], Other] | Any],
) -> RunnableSerializable[Input, Other]

Runnable "or" operator.

Compose this Runnable with another object to create a RunnableSequence.

PARAMETER DESCRIPTION
other

Another Runnable or a Runnable-like object.

TYPE: Runnable[Any, Other] | Callable[[Iterator[Any]], Iterator[Other]] | Callable[[AsyncIterator[Any]], AsyncIterator[Other]] | Callable[[Any], Other] | Mapping[str, Runnable[Any, Other] | Callable[[Any], Other] | Any]

RETURNS DESCRIPTION
RunnableSerializable[Input, Other]

A new Runnable.

__ror__

__ror__(
    other: Runnable[Other, Any]
    | Callable[[Iterator[Other]], Iterator[Any]]
    | Callable[[AsyncIterator[Other]], AsyncIterator[Any]]
    | Callable[[Other], Any]
    | Mapping[str, Runnable[Other, Any] | Callable[[Other], Any] | Any],
) -> RunnableSerializable[Other, Output]

Runnable "reverse-or" operator.

Compose this Runnable with another object to create a RunnableSequence.

PARAMETER DESCRIPTION
other

Another Runnable or a Runnable-like object.

TYPE: Runnable[Other, Any] | Callable[[Iterator[Other]], Iterator[Any]] | Callable[[AsyncIterator[Other]], AsyncIterator[Any]] | Callable[[Other], Any] | Mapping[str, Runnable[Other, Any] | Callable[[Other], Any] | Any]

RETURNS DESCRIPTION
RunnableSerializable[Other, Output]

A new Runnable.

pipe

pipe(
    *others: Runnable[Any, Other] | Callable[[Any], Other], name: str | None = None
) -> RunnableSerializable[Input, Other]

Pipe Runnable objects.

Compose this Runnable with Runnable-like objects to make a RunnableSequence.

Equivalent to RunnableSequence(self, *others) or self | others[0] | ...

Example
from langchain_core.runnables import RunnableLambda


def add_one(x: int) -> int:
    return x + 1


def mul_two(x: int) -> int:
    return x * 2


runnable_1 = RunnableLambda(add_one)
runnable_2 = RunnableLambda(mul_two)
sequence = runnable_1.pipe(runnable_2)
# Or equivalently:
# sequence = runnable_1 | runnable_2
# sequence = RunnableSequence(first=runnable_1, last=runnable_2)
sequence.invoke(1)
await sequence.ainvoke(1)
# -> 4

sequence.batch([1, 2, 3])
await sequence.abatch([1, 2, 3])
# -> [4, 6, 8]
PARAMETER DESCRIPTION
*others

Other Runnable or Runnable-like objects to compose

TYPE: Runnable[Any, Other] | Callable[[Any], Other] DEFAULT: ()

name

An optional name for the resulting RunnableSequence.

TYPE: str | None DEFAULT: None

RETURNS DESCRIPTION
RunnableSerializable[Input, Other]

A new Runnable.

pick

pick(keys: str | list[str]) -> RunnableSerializable[Any, Any]

Pick keys from the output dict of this Runnable.

Pick a single key:

import json

from langchain_core.runnables import RunnableLambda, RunnableMap

as_str = RunnableLambda(str)
as_json = RunnableLambda(json.loads)
chain = RunnableMap(str=as_str, json=as_json)

chain.invoke("[1, 2, 3]")
# -> {"str": "[1, 2, 3]", "json": [1, 2, 3]}

json_only_chain = chain.pick("json")
json_only_chain.invoke("[1, 2, 3]")
# -> [1, 2, 3]

Pick a list of keys:

from typing import Any

import json

from langchain_core.runnables import RunnableLambda, RunnableMap

as_str = RunnableLambda(str)
as_json = RunnableLambda(json.loads)


def as_bytes(x: Any) -> bytes:
    return bytes(x, "utf-8")


chain = RunnableMap(str=as_str, json=as_json, bytes=RunnableLambda(as_bytes))

chain.invoke("[1, 2, 3]")
# -> {"str": "[1, 2, 3]", "json": [1, 2, 3], "bytes": b"[1, 2, 3]"}

json_and_bytes_chain = chain.pick(["json", "bytes"])
json_and_bytes_chain.invoke("[1, 2, 3]")
# -> {"json": [1, 2, 3], "bytes": b"[1, 2, 3]"}
PARAMETER DESCRIPTION
keys

A key or list of keys to pick from the output dict.

TYPE: str | list[str]

RETURNS DESCRIPTION
RunnableSerializable[Any, Any]

a new Runnable.

assign

Assigns new fields to the dict output of this Runnable.

from langchain_community.llms.fake import FakeStreamingListLLM
from langchain_core.output_parsers import StrOutputParser
from langchain_core.prompts import SystemMessagePromptTemplate
from langchain_core.runnables import Runnable
from operator import itemgetter

prompt = (
    SystemMessagePromptTemplate.from_template("You are a nice assistant.")
    + "{question}"
)
model = FakeStreamingListLLM(responses=["foo-lish"])

chain: Runnable = prompt | model | {"str": StrOutputParser()}

chain_with_assign = chain.assign(hello=itemgetter("str") | model)

print(chain_with_assign.input_schema.model_json_schema())
# {'title': 'PromptInput', 'type': 'object', 'properties':
{'question': {'title': 'Question', 'type': 'string'}}}
print(chain_with_assign.output_schema.model_json_schema())
# {'title': 'RunnableSequenceOutput', 'type': 'object', 'properties':
{'str': {'title': 'Str',
'type': 'string'}, 'hello': {'title': 'Hello', 'type': 'string'}}}
PARAMETER DESCRIPTION
**kwargs

A mapping of keys to Runnable or Runnable-like objects that will be invoked with the entire output dict of this Runnable.

TYPE: Runnable[dict[str, Any], Any] | Callable[[dict[str, Any]], Any] | Mapping[str, Runnable[dict[str, Any], Any] | Callable[[dict[str, Any]], Any]] DEFAULT: {}

RETURNS DESCRIPTION
RunnableSerializable[Any, Any]

A new Runnable.

invoke

invoke(
    input: LanguageModelInput,
    config: RunnableConfig | None = None,
    *,
    stop: list[str] | None = None,
    **kwargs: Any,
) -> AIMessage

Transform a single input into an output.

PARAMETER DESCRIPTION
input

The input to the Runnable.

TYPE: Input

config

A config to use when invoking the Runnable. The config supports standard keys like 'tags', 'metadata' for tracing purposes, 'max_concurrency' for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details.

TYPE: RunnableConfig | None DEFAULT: None

RETURNS DESCRIPTION
Output

The output of the Runnable.

ainvoke async

ainvoke(
    input: LanguageModelInput,
    config: RunnableConfig | None = None,
    *,
    stop: list[str] | None = None,
    **kwargs: Any,
) -> AIMessage

Transform a single input into an output.

PARAMETER DESCRIPTION
input

The input to the Runnable.

TYPE: Input

config

A config to use when invoking the Runnable. The config supports standard keys like 'tags', 'metadata' for tracing purposes, 'max_concurrency' for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details.

TYPE: RunnableConfig | None DEFAULT: None

RETURNS DESCRIPTION
Output

The output of the Runnable.

batch

batch(
    inputs: list[Input],
    config: RunnableConfig | list[RunnableConfig] | None = None,
    *,
    return_exceptions: bool = False,
    **kwargs: Any | None,
) -> list[Output]

Default implementation runs invoke in parallel using a thread pool executor.

The default implementation of batch works well for IO bound runnables.

Subclasses must override this method if they can batch more efficiently; e.g., if the underlying Runnable uses an API which supports a batch mode.

PARAMETER DESCRIPTION
inputs

A list of inputs to the Runnable.

TYPE: list[Input]

config

A config to use when invoking the Runnable. The config supports standard keys like 'tags', 'metadata' for tracing purposes, 'max_concurrency' for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details.

TYPE: RunnableConfig | list[RunnableConfig] | None DEFAULT: None

return_exceptions

Whether to return exceptions instead of raising them.

TYPE: bool DEFAULT: False

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

RETURNS DESCRIPTION
list[Output]

A list of outputs from the Runnable.

batch_as_completed

batch_as_completed(
    inputs: Sequence[Input],
    config: RunnableConfig | Sequence[RunnableConfig] | None = None,
    *,
    return_exceptions: bool = False,
    **kwargs: Any | None,
) -> Iterator[tuple[int, Output | Exception]]

Run invoke in parallel on a list of inputs.

Yields results as they complete.

PARAMETER DESCRIPTION
inputs

A list of inputs to the Runnable.

TYPE: Sequence[Input]

config

A config to use when invoking the Runnable. The config supports standard keys like 'tags', 'metadata' for tracing purposes, 'max_concurrency' for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details.

TYPE: RunnableConfig | Sequence[RunnableConfig] | None DEFAULT: None

return_exceptions

Whether to return exceptions instead of raising them.

TYPE: bool DEFAULT: False

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

YIELDS DESCRIPTION
tuple[int, Output | Exception]

Tuples of the index of the input and the output from the Runnable.

abatch async

abatch(
    inputs: list[Input],
    config: RunnableConfig | list[RunnableConfig] | None = None,
    *,
    return_exceptions: bool = False,
    **kwargs: Any | None,
) -> list[Output]

Default implementation runs ainvoke in parallel using asyncio.gather.

The default implementation of batch works well for IO bound runnables.

Subclasses must override this method if they can batch more efficiently; e.g., if the underlying Runnable uses an API which supports a batch mode.

PARAMETER DESCRIPTION
inputs

A list of inputs to the Runnable.

TYPE: list[Input]

config

A config to use when invoking the Runnable. The config supports standard keys like 'tags', 'metadata' for tracing purposes, 'max_concurrency' for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details.

TYPE: RunnableConfig | list[RunnableConfig] | None DEFAULT: None

return_exceptions

Whether to return exceptions instead of raising them.

TYPE: bool DEFAULT: False

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

RETURNS DESCRIPTION
list[Output]

A list of outputs from the Runnable.

abatch_as_completed async

abatch_as_completed(
    inputs: Sequence[Input],
    config: RunnableConfig | Sequence[RunnableConfig] | None = None,
    *,
    return_exceptions: bool = False,
    **kwargs: Any | None,
) -> AsyncIterator[tuple[int, Output | Exception]]

Run ainvoke in parallel on a list of inputs.

Yields results as they complete.

PARAMETER DESCRIPTION
inputs

A list of inputs to the Runnable.

TYPE: Sequence[Input]

config

A config to use when invoking the Runnable. The config supports standard keys like 'tags', 'metadata' for tracing purposes, 'max_concurrency' for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details.

TYPE: RunnableConfig | Sequence[RunnableConfig] | None DEFAULT: None

return_exceptions

Whether to return exceptions instead of raising them.

TYPE: bool DEFAULT: False

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

YIELDS DESCRIPTION
AsyncIterator[tuple[int, Output | Exception]]

A tuple of the index of the input and the output from the Runnable.

stream

stream(
    input: LanguageModelInput,
    config: RunnableConfig | None = None,
    *,
    stop: list[str] | None = None,
    **kwargs: Any,
) -> Iterator[AIMessageChunk]

Default implementation of stream, which calls invoke.

Subclasses must override this method if they support streaming output.

PARAMETER DESCRIPTION
input

The input to the Runnable.

TYPE: Input

config

The config to use for the Runnable.

TYPE: RunnableConfig | None DEFAULT: None

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

YIELDS DESCRIPTION
Output

The output of the Runnable.

astream async

astream(
    input: LanguageModelInput,
    config: RunnableConfig | None = None,
    *,
    stop: list[str] | None = None,
    **kwargs: Any,
) -> AsyncIterator[AIMessageChunk]

Default implementation of astream, which calls ainvoke.

Subclasses must override this method if they support streaming output.

PARAMETER DESCRIPTION
input

The input to the Runnable.

TYPE: Input

config

The config to use for the Runnable.

TYPE: RunnableConfig | None DEFAULT: None

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

YIELDS DESCRIPTION
AsyncIterator[Output]

The output of the Runnable.

astream_log async

astream_log(
    input: Any,
    config: RunnableConfig | None = None,
    *,
    diff: bool = True,
    with_streamed_output_list: bool = True,
    include_names: Sequence[str] | None = None,
    include_types: Sequence[str] | None = None,
    include_tags: Sequence[str] | None = None,
    exclude_names: Sequence[str] | None = None,
    exclude_types: Sequence[str] | None = None,
    exclude_tags: Sequence[str] | None = None,
    **kwargs: Any,
) -> AsyncIterator[RunLogPatch] | AsyncIterator[RunLog]

Stream all output from a Runnable, as reported to the callback system.

This includes all inner runs of LLMs, Retrievers, Tools, etc.

Output is streamed as Log objects, which include a list of Jsonpatch ops that describe how the state of the run has changed in each step, and the final state of the run.

The Jsonpatch ops can be applied in order to construct state.

PARAMETER DESCRIPTION
input

The input to the Runnable.

TYPE: Any

config

The config to use for the Runnable.

TYPE: RunnableConfig | None DEFAULT: None

diff

Whether to yield diffs between each step or the current state.

TYPE: bool DEFAULT: True

with_streamed_output_list

Whether to yield the streamed_output list.

TYPE: bool DEFAULT: True

include_names

Only include logs with these names.

TYPE: Sequence[str] | None DEFAULT: None

include_types

Only include logs with these types.

TYPE: Sequence[str] | None DEFAULT: None

include_tags

Only include logs with these tags.

TYPE: Sequence[str] | None DEFAULT: None

exclude_names

Exclude logs with these names.

TYPE: Sequence[str] | None DEFAULT: None

exclude_types

Exclude logs with these types.

TYPE: Sequence[str] | None DEFAULT: None

exclude_tags

Exclude logs with these tags.

TYPE: Sequence[str] | None DEFAULT: None

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any DEFAULT: {}

YIELDS DESCRIPTION
AsyncIterator[RunLogPatch] | AsyncIterator[RunLog]

A RunLogPatch or RunLog object.

astream_events async

astream_events(
    input: Any,
    config: RunnableConfig | None = None,
    *,
    version: Literal["v1", "v2"] = "v2",
    include_names: Sequence[str] | None = None,
    include_types: Sequence[str] | None = None,
    include_tags: Sequence[str] | None = None,
    exclude_names: Sequence[str] | None = None,
    exclude_types: Sequence[str] | None = None,
    exclude_tags: Sequence[str] | None = None,
    **kwargs: Any,
) -> AsyncIterator[StreamEvent]

Generate a stream of events.

Use to create an iterator over StreamEvent that provide real-time information about the progress of the Runnable, including StreamEvent from intermediate results.

A StreamEvent is a dictionary with the following schema:

  • event: Event names are of the format: on_[runnable_type]_(start|stream|end).
  • name: The name of the Runnable that generated the event.
  • run_id: Randomly generated ID associated with the given execution of the Runnable that emitted the event. A child Runnable that gets invoked as part of the execution of a parent Runnable is assigned its own unique ID.
  • parent_ids: The IDs of the parent runnables that generated the event. The root Runnable will have an empty list. The order of the parent IDs is from the root to the immediate parent. Only available for v2 version of the API. The v1 version of the API will return an empty list.
  • tags: The tags of the Runnable that generated the event.
  • metadata: The metadata of the Runnable that generated the event.
  • data: The data associated with the event. The contents of this field depend on the type of event. See the table below for more details.

Below is a table that illustrates some events that might be emitted by various chains. Metadata fields have been omitted from the table for brevity. Chain definitions have been included after the table.

Note

This reference table is for the v2 version of the schema.

event name chunk input output
on_chat_model_start '[model name]' {"messages": [[SystemMessage, HumanMessage]]}
on_chat_model_stream '[model name]' AIMessageChunk(content="hello")
on_chat_model_end '[model name]' {"messages": [[SystemMessage, HumanMessage]]} AIMessageChunk(content="hello world")
on_llm_start '[model name]' {'input': 'hello'}
on_llm_stream '[model name]' 'Hello'
on_llm_end '[model name]' 'Hello human!'
on_chain_start 'format_docs'
on_chain_stream 'format_docs' 'hello world!, goodbye world!'
on_chain_end 'format_docs' [Document(...)] 'hello world!, goodbye world!'
on_tool_start 'some_tool' {"x": 1, "y": "2"}
on_tool_end 'some_tool' {"x": 1, "y": "2"}
on_retriever_start '[retriever name]' {"query": "hello"}
on_retriever_end '[retriever name]' {"query": "hello"} [Document(...), ..]
on_prompt_start '[template_name]' {"question": "hello"}
on_prompt_end '[template_name]' {"question": "hello"} ChatPromptValue(messages: [SystemMessage, ...])

In addition to the standard events, users can also dispatch custom events (see example below).

Custom events will be only be surfaced with in the v2 version of the API!

A custom event has following format:

Attribute Type Description
name str A user defined name for the event.
data Any The data associated with the event. This can be anything, though we suggest making it JSON serializable.

Here are declarations associated with the standard events shown above:

format_docs:

def format_docs(docs: list[Document]) -> str:
    '''Format the docs.'''
    return ", ".join([doc.page_content for doc in docs])


format_docs = RunnableLambda(format_docs)

some_tool:

@tool
def some_tool(x: int, y: str) -> dict:
    '''Some_tool.'''
    return {"x": x, "y": y}

prompt:

template = ChatPromptTemplate.from_messages(
    [
        ("system", "You are Cat Agent 007"),
        ("human", "{question}"),
    ]
).with_config({"run_name": "my_template", "tags": ["my_template"]})

For instance:

from langchain_core.runnables import RunnableLambda


async def reverse(s: str) -> str:
    return s[::-1]


chain = RunnableLambda(func=reverse)

events = [event async for event in chain.astream_events("hello", version="v2")]

# Will produce the following events
# (run_id, and parent_ids has been omitted for brevity):
[
    {
        "data": {"input": "hello"},
        "event": "on_chain_start",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
    {
        "data": {"chunk": "olleh"},
        "event": "on_chain_stream",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
    {
        "data": {"output": "olleh"},
        "event": "on_chain_end",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
]
Example: Dispatch Custom Event
from langchain_core.callbacks.manager import (
    adispatch_custom_event,
)
from langchain_core.runnables import RunnableLambda, RunnableConfig
import asyncio


async def slow_thing(some_input: str, config: RunnableConfig) -> str:
    """Do something that takes a long time."""
    await asyncio.sleep(1) # Placeholder for some slow operation
    await adispatch_custom_event(
        "progress_event",
        {"message": "Finished step 1 of 3"},
        config=config # Must be included for python < 3.10
    )
    await asyncio.sleep(1) # Placeholder for some slow operation
    await adispatch_custom_event(
        "progress_event",
        {"message": "Finished step 2 of 3"},
        config=config # Must be included for python < 3.10
    )
    await asyncio.sleep(1) # Placeholder for some slow operation
    return "Done"

slow_thing = RunnableLambda(slow_thing)

async for event in slow_thing.astream_events("some_input", version="v2"):
    print(event)
PARAMETER DESCRIPTION
input

The input to the Runnable.

TYPE: Any

config

The config to use for the Runnable.

TYPE: RunnableConfig | None DEFAULT: None

version

The version of the schema to use either 'v2' or 'v1'. Users should use 'v2'. 'v1' is for backwards compatibility and will be deprecated in 0.4.0. No default will be assigned until the API is stabilized. custom events will only be surfaced in 'v2'.

TYPE: Literal['v1', 'v2'] DEFAULT: 'v2'

include_names

Only include events from Runnable objects with matching names.

TYPE: Sequence[str] | None DEFAULT: None

include_types

Only include events from Runnable objects with matching types.

TYPE: Sequence[str] | None DEFAULT: None

include_tags

Only include events from Runnable objects with matching tags.

TYPE: Sequence[str] | None DEFAULT: None

exclude_names

Exclude events from Runnable objects with matching names.

TYPE: Sequence[str] | None DEFAULT: None

exclude_types

Exclude events from Runnable objects with matching types.

TYPE: Sequence[str] | None DEFAULT: None

exclude_tags

Exclude events from Runnable objects with matching tags.

TYPE: Sequence[str] | None DEFAULT: None

**kwargs

Additional keyword arguments to pass to the Runnable. These will be passed to astream_log as this implementation of astream_events is built on top of astream_log.

TYPE: Any DEFAULT: {}

YIELDS DESCRIPTION
AsyncIterator[StreamEvent]

An async stream of StreamEvent.

RAISES DESCRIPTION
NotImplementedError

If the version is not 'v1' or 'v2'.

transform

transform(
    input: Iterator[Input], config: RunnableConfig | None = None, **kwargs: Any | None
) -> Iterator[Output]

Transform inputs to outputs.

Default implementation of transform, which buffers input and calls astream.

Subclasses must override this method if they can start producing output while input is still being generated.

PARAMETER DESCRIPTION
input

An iterator of inputs to the Runnable.

TYPE: Iterator[Input]

config

The config to use for the Runnable.

TYPE: RunnableConfig | None DEFAULT: None

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

YIELDS DESCRIPTION
Output

The output of the Runnable.

atransform async

atransform(
    input: AsyncIterator[Input],
    config: RunnableConfig | None = None,
    **kwargs: Any | None,
) -> AsyncIterator[Output]

Transform inputs to outputs.

Default implementation of atransform, which buffers input and calls astream.

Subclasses must override this method if they can start producing output while input is still being generated.

PARAMETER DESCRIPTION
input

An async iterator of inputs to the Runnable.

TYPE: AsyncIterator[Input]

config

The config to use for the Runnable.

TYPE: RunnableConfig | None DEFAULT: None

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any | None DEFAULT: {}

YIELDS DESCRIPTION
AsyncIterator[Output]

The output of the Runnable.

bind

bind(**kwargs: Any) -> Runnable[Input, Output]

Bind arguments to a Runnable, returning a new Runnable.

Useful when a Runnable in a chain requires an argument that is not in the output of the previous Runnable or included in the user input.

PARAMETER DESCRIPTION
**kwargs

The arguments to bind to the Runnable.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
Runnable[Input, Output]

A new Runnable with the arguments bound.

Example
from langchain_ollama import ChatOllama
from langchain_core.output_parsers import StrOutputParser

model = ChatOllama(model="llama3.1")

# Without bind
chain = model | StrOutputParser()

chain.invoke("Repeat quoted words exactly: 'One two three four five.'")
# Output is 'One two three four five.'

# With bind
chain = model.bind(stop=["three"]) | StrOutputParser()

chain.invoke("Repeat quoted words exactly: 'One two three four five.'")
# Output is 'One two'

with_config

with_config(
    config: RunnableConfig | None = None, **kwargs: Any
) -> Runnable[Input, Output]

Bind config to a Runnable, returning a new Runnable.

PARAMETER DESCRIPTION
config

The config to bind to the Runnable.

TYPE: RunnableConfig | None DEFAULT: None

**kwargs

Additional keyword arguments to pass to the Runnable.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
Runnable[Input, Output]

A new Runnable with the config bound.

with_listeners

with_listeners(
    *,
    on_start: Callable[[Run], None]
    | Callable[[Run, RunnableConfig], None]
    | None = None,
    on_end: Callable[[Run], None] | Callable[[Run, RunnableConfig], None] | None = None,
    on_error: Callable[[Run], None]
    | Callable[[Run, RunnableConfig], None]
    | None = None,
) -> Runnable[Input, Output]

Bind lifecycle listeners to a Runnable, returning a new Runnable.

The Run object contains information about the run, including its id, type, input, output, error, start_time, end_time, and any tags or metadata added to the run.

PARAMETER DESCRIPTION
on_start

Called before the Runnable starts running, with the Run object.

TYPE: Callable[[Run], None] | Callable[[Run, RunnableConfig], None] | None DEFAULT: None

on_end

Called after the Runnable finishes running, with the Run object.

TYPE: Callable[[Run], None] | Callable[[Run, RunnableConfig], None] | None DEFAULT: None

on_error

Called if the Runnable throws an error, with the Run object.

TYPE: Callable[[Run], None] | Callable[[Run, RunnableConfig], None] | None DEFAULT: None

RETURNS DESCRIPTION
Runnable[Input, Output]

A new Runnable with the listeners bound.

Example
from langchain_core.runnables import RunnableLambda
from langchain_core.tracers.schemas import Run

import time


def test_runnable(time_to_sleep: int):
    time.sleep(time_to_sleep)


def fn_start(run_obj: Run):
    print("start_time:", run_obj.start_time)


def fn_end(run_obj: Run):
    print("end_time:", run_obj.end_time)


chain = RunnableLambda(test_runnable).with_listeners(
    on_start=fn_start, on_end=fn_end
)
chain.invoke(2)

with_alisteners

with_alisteners(
    *,
    on_start: AsyncListener | None = None,
    on_end: AsyncListener | None = None,
    on_error: AsyncListener | None = None,
) -> Runnable[Input, Output]

Bind async lifecycle listeners to a Runnable.

Returns a new Runnable.

The Run object contains information about the run, including its id, type, input, output, error, start_time, end_time, and any tags or metadata added to the run.

PARAMETER DESCRIPTION
on_start

Called asynchronously before the Runnable starts running, with the Run object.

TYPE: AsyncListener | None DEFAULT: None

on_end

Called asynchronously after the Runnable finishes running, with the Run object.

TYPE: AsyncListener | None DEFAULT: None

on_error

Called asynchronously if the Runnable throws an error, with the Run object.

TYPE: AsyncListener | None DEFAULT: None

RETURNS DESCRIPTION
Runnable[Input, Output]

A new Runnable with the listeners bound.

Example
from langchain_core.runnables import RunnableLambda, Runnable
from datetime import datetime, timezone
import time
import asyncio

def format_t(timestamp: float) -> str:
    return datetime.fromtimestamp(timestamp, tz=timezone.utc).isoformat()

async def test_runnable(time_to_sleep: int):
    print(f"Runnable[{time_to_sleep}s]: starts at {format_t(time.time())}")
    await asyncio.sleep(time_to_sleep)
    print(f"Runnable[{time_to_sleep}s]: ends at {format_t(time.time())}")

async def fn_start(run_obj: Runnable):
    print(f"on start callback starts at {format_t(time.time())}")
    await asyncio.sleep(3)
    print(f"on start callback ends at {format_t(time.time())}")

async def fn_end(run_obj: Runnable):
    print(f"on end callback starts at {format_t(time.time())}")
    await asyncio.sleep(2)
    print(f"on end callback ends at {format_t(time.time())}")

runnable = RunnableLambda(test_runnable).with_alisteners(
    on_start=fn_start,
    on_end=fn_end
)
async def concurrent_runs():
    await asyncio.gather(runnable.ainvoke(2), runnable.ainvoke(3))

asyncio.run(concurrent_runs())
Result:
on start callback starts at 2025-03-01T07:05:22.875378+00:00
on start callback starts at 2025-03-01T07:05:22.875495+00:00
on start callback ends at 2025-03-01T07:05:25.878862+00:00
on start callback ends at 2025-03-01T07:05:25.878947+00:00
Runnable[2s]: starts at 2025-03-01T07:05:25.879392+00:00
Runnable[3s]: starts at 2025-03-01T07:05:25.879804+00:00
Runnable[2s]: ends at 2025-03-01T07:05:27.881998+00:00
on end callback starts at 2025-03-01T07:05:27.882360+00:00
Runnable[3s]: ends at 2025-03-01T07:05:28.881737+00:00
on end callback starts at 2025-03-01T07:05:28.882428+00:00
on end callback ends at 2025-03-01T07:05:29.883893+00:00
on end callback ends at 2025-03-01T07:05:30.884831+00:00

with_types

with_types(
    *, input_type: type[Input] | None = None, output_type: type[Output] | None = None
) -> Runnable[Input, Output]

Bind input and output types to a Runnable, returning a new Runnable.

PARAMETER DESCRIPTION
input_type

The input type to bind to the Runnable.

TYPE: type[Input] | None DEFAULT: None

output_type

The output type to bind to the Runnable.

TYPE: type[Output] | None DEFAULT: None

RETURNS DESCRIPTION
Runnable[Input, Output]

A new Runnable with the types bound.

with_retry

with_retry(
    *,
    retry_if_exception_type: tuple[type[BaseException], ...] = (Exception,),
    wait_exponential_jitter: bool = True,
    exponential_jitter_params: ExponentialJitterParams | None = None,
    stop_after_attempt: int = 3,
) -> Runnable[Input, Output]

Create a new Runnable that retries the original Runnable on exceptions.

PARAMETER DESCRIPTION
retry_if_exception_type

A tuple of exception types to retry on.

TYPE: tuple[type[BaseException], ...] DEFAULT: (Exception,)

wait_exponential_jitter

Whether to add jitter to the wait time between retries.

TYPE: bool DEFAULT: True

stop_after_attempt

The maximum number of attempts to make before giving up.

TYPE: int DEFAULT: 3

exponential_jitter_params

Parameters for tenacity.wait_exponential_jitter. Namely: initial, max, exp_base, and jitter (all float values).

TYPE: ExponentialJitterParams | None DEFAULT: None

RETURNS DESCRIPTION
Runnable[Input, Output]

A new Runnable that retries the original Runnable on exceptions.

Example
from langchain_core.runnables import RunnableLambda

count = 0


def _lambda(x: int) -> None:
    global count
    count = count + 1
    if x == 1:
        raise ValueError("x is 1")
    else:
        pass


runnable = RunnableLambda(_lambda)
try:
    runnable.with_retry(
        stop_after_attempt=2,
        retry_if_exception_type=(ValueError,),
    ).invoke(1)
except ValueError:
    pass

assert count == 2

map

map() -> Runnable[list[Input], list[Output]]

Return a new Runnable that maps a list of inputs to a list of outputs.

Calls invoke with each input.

RETURNS DESCRIPTION
Runnable[list[Input], list[Output]]

A new Runnable that maps a list of inputs to a list of outputs.

Example
from langchain_core.runnables import RunnableLambda


def _lambda(x: int) -> int:
    return x + 1


runnable = RunnableLambda(_lambda)
print(runnable.map().invoke([1, 2, 3]))  # [2, 3, 4]

with_fallbacks

with_fallbacks(
    fallbacks: Sequence[Runnable[Input, Output]],
    *,
    exceptions_to_handle: tuple[type[BaseException], ...] = (Exception,),
    exception_key: str | None = None,
) -> RunnableWithFallbacks[Input, Output]

Add fallbacks to a Runnable, returning a new Runnable.

The new Runnable will try the original Runnable, and then each fallback in order, upon failures.

PARAMETER DESCRIPTION
fallbacks

A sequence of runnables to try if the original Runnable fails.

TYPE: Sequence[Runnable[Input, Output]]

exceptions_to_handle

A tuple of exception types to handle.

TYPE: tuple[type[BaseException], ...] DEFAULT: (Exception,)

exception_key

If string is specified then handled exceptions will be passed to fallbacks as part of the input under the specified key. If None, exceptions will not be passed to fallbacks. If used, the base Runnable and its fallbacks must accept a dictionary as input.

TYPE: str | None DEFAULT: None

RETURNS DESCRIPTION
RunnableWithFallbacks[Input, Output]

A new Runnable that will try the original Runnable, and then each Fallback in order, upon failures.

Example
from typing import Iterator

from langchain_core.runnables import RunnableGenerator


def _generate_immediate_error(input: Iterator) -> Iterator[str]:
    raise ValueError()
    yield ""


def _generate(input: Iterator) -> Iterator[str]:
    yield from "foo bar"


runnable = RunnableGenerator(_generate_immediate_error).with_fallbacks(
    [RunnableGenerator(_generate)]
)
print("".join(runnable.stream({})))  # foo bar
PARAMETER DESCRIPTION
fallbacks

A sequence of runnables to try if the original Runnable fails.

TYPE: Sequence[Runnable[Input, Output]]

exceptions_to_handle

A tuple of exception types to handle.

TYPE: tuple[type[BaseException], ...] DEFAULT: (Exception,)

exception_key

If string is specified then handled exceptions will be passed to fallbacks as part of the input under the specified key. If None, exceptions will not be passed to fallbacks. If used, the base Runnable and its fallbacks must accept a dictionary as input.

TYPE: str | None DEFAULT: None

RETURNS DESCRIPTION
RunnableWithFallbacks[Input, Output]

A new Runnable that will try the original Runnable, and then each Fallback in order, upon failures.

as_tool

as_tool(
    args_schema: type[BaseModel] | None = None,
    *,
    name: str | None = None,
    description: str | None = None,
    arg_types: dict[str, type] | None = None,
) -> BaseTool

Create a BaseTool from a Runnable.

as_tool will instantiate a BaseTool with a name, description, and args_schema from a Runnable. Where possible, schemas are inferred from runnable.get_input_schema. Alternatively (e.g., if the Runnable takes a dict as input and the specific dict keys are not typed), the schema can be specified directly with args_schema. You can also pass arg_types to just specify the required arguments and their types.

PARAMETER DESCRIPTION
args_schema

The schema for the tool.

TYPE: type[BaseModel] | None DEFAULT: None

name

The name of the tool.

TYPE: str | None DEFAULT: None

description

The description of the tool.

TYPE: str | None DEFAULT: None

arg_types

A dictionary of argument names to types.

TYPE: dict[str, type] | None DEFAULT: None

RETURNS DESCRIPTION
BaseTool

A BaseTool instance.

Typed dict input:

from typing_extensions import TypedDict
from langchain_core.runnables import RunnableLambda


class Args(TypedDict):
    a: int
    b: list[int]


def f(x: Args) -> str:
    return str(x["a"] * max(x["b"]))


runnable = RunnableLambda(f)
as_tool = runnable.as_tool()
as_tool.invoke({"a": 3, "b": [1, 2]})

dict input, specifying schema via args_schema:

from typing import Any
from pydantic import BaseModel, Field
from langchain_core.runnables import RunnableLambda

def f(x: dict[str, Any]) -> str:
    return str(x["a"] * max(x["b"]))

class FSchema(BaseModel):
    """Apply a function to an integer and list of integers."""

    a: int = Field(..., description="Integer")
    b: list[int] = Field(..., description="List of ints")

runnable = RunnableLambda(f)
as_tool = runnable.as_tool(FSchema)
as_tool.invoke({"a": 3, "b": [1, 2]})

dict input, specifying schema via arg_types:

from typing import Any
from langchain_core.runnables import RunnableLambda


def f(x: dict[str, Any]) -> str:
    return str(x["a"] * max(x["b"]))


runnable = RunnableLambda(f)
as_tool = runnable.as_tool(arg_types={"a": int, "b": list[int]})
as_tool.invoke({"a": 3, "b": [1, 2]})

String input:

from langchain_core.runnables import RunnableLambda


def f(x: str) -> str:
    return x + "a"


def g(x: str) -> str:
    return x + "z"


runnable = RunnableLambda(f) | g
as_tool = runnable.as_tool()
as_tool.invoke("b")

Added in version 0.2.14

__init__

__init__(*args: Any, **kwargs: Any) -> None

lc_id classmethod

lc_id() -> list[str]

Return a unique identifier for this class for serialization purposes.

The unique identifier is a list of strings that describes the path to the object.

For example, for the class langchain.llms.openai.OpenAI, the id is ["langchain", "llms", "openai", "OpenAI"].

to_json

to_json() -> SerializedConstructor | SerializedNotImplemented

Serialize the Runnable to JSON.

RETURNS DESCRIPTION
SerializedConstructor | SerializedNotImplemented

A JSON-serializable representation of the Runnable.

to_json_not_implemented

to_json_not_implemented() -> SerializedNotImplemented

Serialize a "not implemented" object.

RETURNS DESCRIPTION
SerializedNotImplemented

SerializedNotImplemented.

configurable_fields

configurable_fields(
    **kwargs: AnyConfigurableField,
) -> RunnableSerializable[Input, Output]

Configure particular Runnable fields at runtime.

PARAMETER DESCRIPTION
**kwargs

A dictionary of ConfigurableField instances to configure.

TYPE: AnyConfigurableField DEFAULT: {}

RAISES DESCRIPTION
ValueError

If a configuration key is not found in the Runnable.

RETURNS DESCRIPTION
RunnableSerializable[Input, Output]

A new Runnable with the fields configured.

from langchain_core.runnables import ConfigurableField
from langchain_openai import ChatOpenAI

model = ChatOpenAI(max_tokens=20).configurable_fields(
    max_tokens=ConfigurableField(
        id="output_token_number",
        name="Max tokens in the output",
        description="The maximum number of tokens in the output",
    )
)

# max_tokens = 20
print("max_tokens_20: ", model.invoke("tell me something about chess").content)

# max_tokens = 200
print(
    "max_tokens_200: ",
    model.with_config(configurable={"output_token_number": 200})
    .invoke("tell me something about chess")
    .content,
)

configurable_alternatives

configurable_alternatives(
    which: ConfigurableField,
    *,
    default_key: str = "default",
    prefix_keys: bool = False,
    **kwargs: Runnable[Input, Output] | Callable[[], Runnable[Input, Output]],
) -> RunnableSerializable[Input, Output]

Configure alternatives for Runnable objects that can be set at runtime.

PARAMETER DESCRIPTION
which

The ConfigurableField instance that will be used to select the alternative.

TYPE: ConfigurableField

default_key

The default key to use if no alternative is selected.

TYPE: str DEFAULT: 'default'

prefix_keys

Whether to prefix the keys with the ConfigurableField id.

TYPE: bool DEFAULT: False

**kwargs

A dictionary of keys to Runnable instances or callables that return Runnable instances.

TYPE: Runnable[Input, Output] | Callable[[], Runnable[Input, Output]] DEFAULT: {}

RETURNS DESCRIPTION
RunnableSerializable[Input, Output]

A new Runnable with the alternatives configured.

from langchain_anthropic import ChatAnthropic
from langchain_core.runnables.utils import ConfigurableField
from langchain_openai import ChatOpenAI

model = ChatAnthropic(
    model_name="claude-3-7-sonnet-20250219"
).configurable_alternatives(
    ConfigurableField(id="llm"),
    default_key="anthropic",
    openai=ChatOpenAI(),
)

# uses the default model ChatAnthropic
print(model.invoke("which organization created you?").content)

# uses ChatOpenAI
print(
    model.with_config(configurable={"llm": "openai"})
    .invoke("which organization created you?")
    .content
)

set_verbose

set_verbose(verbose: bool | None) -> bool

If verbose is None, set it.

This allows users to pass in None as verbose to access the global setting.

PARAMETER DESCRIPTION
verbose

The verbosity setting to use.

TYPE: bool | None

RETURNS DESCRIPTION
bool

The verbosity setting to use.

generate_prompt

generate_prompt(
    prompts: list[PromptValue],
    stop: list[str] | None = None,
    callbacks: Callbacks = None,
    **kwargs: Any,
) -> LLMResult

Pass a sequence of prompts to the model and return model generations.

This method should make use of batched calls for models that expose a batched API.

Use this method when you want to:

  1. Take advantage of batched calls,
  2. Need more output from the model than just the top generated value,
  3. Are building chains that are agnostic to the underlying language model type (e.g., pure text completion models vs chat models).
PARAMETER DESCRIPTION
prompts

List of PromptValue objects. A PromptValue is an object that can be converted to match the format of any language model (string for pure text generation models and BaseMessage objects for chat models).

TYPE: list[PromptValue]

stop

Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.

TYPE: list[str] | None DEFAULT: None

callbacks

Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.

TYPE: Callbacks DEFAULT: None

**kwargs

Arbitrary additional keyword arguments. These are usually passed to the model provider API call.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
LLMResult

An LLMResult, which contains a list of candidate Generation objects for each input prompt and additional model provider-specific output.

agenerate_prompt async

agenerate_prompt(
    prompts: list[PromptValue],
    stop: list[str] | None = None,
    callbacks: Callbacks = None,
    **kwargs: Any,
) -> LLMResult

Asynchronously pass a sequence of prompts and return model generations.

This method should make use of batched calls for models that expose a batched API.

Use this method when you want to:

  1. Take advantage of batched calls,
  2. Need more output from the model than just the top generated value,
  3. Are building chains that are agnostic to the underlying language model type (e.g., pure text completion models vs chat models).
PARAMETER DESCRIPTION
prompts

List of PromptValue objects. A PromptValue is an object that can be converted to match the format of any language model (string for pure text generation models and BaseMessage objects for chat models).

TYPE: list[PromptValue]

stop

Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.

TYPE: list[str] | None DEFAULT: None

callbacks

Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.

TYPE: Callbacks DEFAULT: None

**kwargs

Arbitrary additional keyword arguments. These are usually passed to the model provider API call.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
LLMResult

An LLMResult, which contains a list of candidate Generation objects for each input prompt and additional model provider-specific output.

get_token_ids

get_token_ids(text: str) -> list[int]

Get the tokens present in the text with tiktoken package.

get_num_tokens

get_num_tokens(text: str) -> int

Get the number of tokens present in the text.

Useful for checking if an input fits in a model's context window.

PARAMETER DESCRIPTION
text

The string input to tokenize.

TYPE: str

RETURNS DESCRIPTION
int

The integer number of tokens in the text.

get_num_tokens_from_messages

get_num_tokens_from_messages(
    messages: Sequence[BaseMessage],
    tools: Sequence[dict[str, Any] | type | Callable | BaseTool] | None = None,
) -> int

Calculate num tokens for gpt-3.5-turbo and gpt-4 with tiktoken package.

Warning

You must have the pillow installed if you want to count image tokens if you are specifying the image as a base64 string, and you must have both pillow and httpx installed if you are specifying the image as a URL. If these aren't installed image inputs will be ignored in token counting.

OpenAI reference.

PARAMETER DESCRIPTION
messages

The message inputs to tokenize.

TYPE: Sequence[BaseMessage]

tools

If provided, sequence of dict, BaseModel, function, or BaseTool to be converted to tool schemas.

TYPE: Sequence[dict[str, Any] | type | Callable | BaseTool] | None DEFAULT: None

generate

generate(
    messages: list[list[BaseMessage]],
    stop: list[str] | None = None,
    callbacks: Callbacks = None,
    *,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    run_name: str | None = None,
    run_id: UUID | None = None,
    **kwargs: Any,
) -> LLMResult

Pass a sequence of prompts to the model and return model generations.

This method should make use of batched calls for models that expose a batched API.

Use this method when you want to:

  1. Take advantage of batched calls,
  2. Need more output from the model than just the top generated value,
  3. Are building chains that are agnostic to the underlying language model type (e.g., pure text completion models vs chat models).
PARAMETER DESCRIPTION
messages

List of list of messages.

TYPE: list[list[BaseMessage]]

stop

Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.

TYPE: list[str] | None DEFAULT: None

callbacks

Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.

TYPE: Callbacks DEFAULT: None

tags

The tags to apply.

TYPE: list[str] | None DEFAULT: None

metadata

The metadata to apply.

TYPE: dict[str, Any] | None DEFAULT: None

run_name

The name of the run.

TYPE: str | None DEFAULT: None

run_id

The ID of the run.

TYPE: UUID | None DEFAULT: None

**kwargs

Arbitrary additional keyword arguments. These are usually passed to the model provider API call.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
LLMResult

An LLMResult, which contains a list of candidate Generations for each input prompt and additional model provider-specific output.

agenerate async

agenerate(
    messages: list[list[BaseMessage]],
    stop: list[str] | None = None,
    callbacks: Callbacks = None,
    *,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    run_name: str | None = None,
    run_id: UUID | None = None,
    **kwargs: Any,
) -> LLMResult

Asynchronously pass a sequence of prompts to a model and return generations.

This method should make use of batched calls for models that expose a batched API.

Use this method when you want to:

  1. Take advantage of batched calls,
  2. Need more output from the model than just the top generated value,
  3. Are building chains that are agnostic to the underlying language model type (e.g., pure text completion models vs chat models).
PARAMETER DESCRIPTION
messages

List of list of messages.

TYPE: list[list[BaseMessage]]

stop

Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.

TYPE: list[str] | None DEFAULT: None

callbacks

Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.

TYPE: Callbacks DEFAULT: None

tags

The tags to apply.

TYPE: list[str] | None DEFAULT: None

metadata

The metadata to apply.

TYPE: dict[str, Any] | None DEFAULT: None

run_name

The name of the run.

TYPE: str | None DEFAULT: None

run_id

The ID of the run.

TYPE: UUID | None DEFAULT: None

**kwargs

Arbitrary additional keyword arguments. These are usually passed to the model provider API call.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
LLMResult

An LLMResult, which contains a list of candidate Generations for each input prompt and additional model provider-specific output.

dict

dict(**kwargs: Any) -> dict

Return a dictionary of the LLM.

bind_tools

bind_tools(
    tools: Sequence[dict[str, Any] | type | Callable | BaseTool],
    *,
    tool_choice: dict | str | bool | None = None,
    strict: bool | None = None,
    parallel_tool_calls: bool | None = None,
    **kwargs: Any,
) -> Runnable[LanguageModelInput, AIMessage]

Bind tool-like objects to this chat model.

Assumes model is compatible with OpenAI tool-calling API.

PARAMETER DESCRIPTION
tools

A list of tool definitions to bind to this chat model. Supports any tool definition handled by langchain_core.utils.function_calling.convert_to_openai_tool.

TYPE: Sequence[dict[str, Any] | type | Callable | BaseTool]

tool_choice

Which tool to require the model to call. Options are:

  • str of the form '<<tool_name>>': calls <<tool_name>> tool.
  • 'auto': automatically selects a tool (including no tool).
  • 'none': does not call a tool.
  • 'any' or 'required' or True: force at least one tool to be called.
  • dict of the form {"type": "function", "function": {"name": <<tool_name>>}}: calls <<tool_name>> tool.
  • False or None: no effect, default OpenAI behavior.

TYPE: dict | str | bool | None DEFAULT: None

strict

If True, model output is guaranteed to exactly match the JSON Schema provided in the tool definition. The input schema will also be validated according to the supported schemas. If False, input schema will not be validated and model output will not be validated. If None, strict argument will not be passed to the model.

TYPE: bool | None DEFAULT: None

parallel_tool_calls

Set to False to disable parallel tool use. Defaults to None (no specification, which allows parallel tool use).

TYPE: bool | None DEFAULT: None

kwargs

Any additional parameters are passed directly to bind.

TYPE: Any DEFAULT: {}

build_extra classmethod

build_extra(values: dict[str, Any]) -> Any

Build extra kwargs from additional params that were passed in.

validate_temperature classmethod

validate_temperature(values: dict[str, Any]) -> Any

Validate temperature parameter for different models.

  • gpt-5 models (excluding gpt-5-chat) only allow temperature=1 or unset (Defaults to 1)

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

is_lc_serializable classmethod

is_lc_serializable() -> bool

Check if the class is serializable in langchain.

validate_environment

validate_environment() -> Self

Validate that api key and python package exists in environment.

with_structured_output

with_structured_output(
    schema: _DictOrPydanticClass | None = None,
    *,
    method: Literal["function_calling", "json_mode", "json_schema"] = "json_schema",
    include_raw: bool = False,
    strict: bool | None = None,
    **kwargs: Any,
) -> Runnable[LanguageModelInput, _DictOrPydantic]

Model wrapper that returns outputs formatted to match the given schema.

PARAMETER DESCRIPTION
schema

The output schema. Can be passed in as:

  • a JSON Schema,
  • a TypedDict class,
  • a Pydantic class,
  • or an OpenAI function/tool schema.

If schema is a Pydantic class then the model output will be a Pydantic instance of that class, and the model-generated fields will be validated by the Pydantic class. Otherwise the model output will be a dict and will not be validated.

See langchain_core.utils.function_calling.convert_to_openai_tool for more on how to properly specify types and descriptions of schema fields when specifying a Pydantic or TypedDict class.

TYPE: _DictOrPydanticClass | None DEFAULT: None

method

The method for steering model generation, one of:

  • 'json_schema': Uses OpenAI's Structured Output API. Supported for 'gpt-4o-mini', 'gpt-4o-2024-08-06', 'o1', and later models.
  • 'function_calling': Uses OpenAI's tool-calling (formerly called function calling) API
  • 'json_mode': Uses OpenAI's JSON mode. Note that if using JSON mode then you must include instructions for formatting the output into the desired schema into the model call

Learn more about the differences between the methods and which models support which methods here.

TYPE: Literal['function_calling', 'json_mode', 'json_schema'] DEFAULT: 'json_schema'

include_raw

If False then only the parsed structured output is returned. If an error occurs during model output parsing it will be raised. If True then both the raw model response (a BaseMessage) and the parsed model response will be returned. If an error occurs during output parsing it will be caught and returned as well.

The final output is always a dict with keys 'raw', 'parsed', and 'parsing_error'.

TYPE: bool DEFAULT: False

strict
  • True: Model output is guaranteed to exactly match the schema. The input schema will also be validated according to the supported schemas.
  • False: Input schema will not be validated and model output will not be validated.
  • None: strict argument will not be passed to the model.

If schema is specified via TypedDict or JSON schema, strict is not enabled by default. Pass strict=True to enable it.

Note

strict can only be non-null if method is 'json_schema' or 'function_calling'.

TYPE: bool | None DEFAULT: None

tools

A list of tool-like objects to bind to the chat model. Requires that:

  • method is 'json_schema' (default).
  • strict=True
  • include_raw=True

If a model elects to call a tool, the resulting AIMessage in 'raw' will include tool calls.

Example
from langchain.chat_models import init_chat_model
from pydantic import BaseModel


class ResponseSchema(BaseModel):
    response: str


def get_weather(location: str) -> str:
    \"\"\"Get weather at a location.\"\"\"
    pass

model = init_chat_model("openai:gpt-4o-mini")

structured_model = model.with_structured_output(
    ResponseSchema,
    tools=[get_weather],
    strict=True,
    include_raw=True,
)

structured_model.invoke("What's the weather in Boston?")
{
    "raw": AIMessage(content="", tool_calls=[...], ...),
    "parsing_error": None,
    "parsed": None,
}

kwargs

Additional keyword args are passed through to the model.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
Runnable[LanguageModelInput, _DictOrPydantic]

A Runnable that takes same inputs as a langchain_core.language_models.chat.BaseChatModel. If include_raw is False and schema is a Pydantic class, Runnable outputs an instance of schema (i.e., a Pydantic object). Otherwise, if include_raw is False then Runnable outputs a dict.

If include_raw is True, then Runnable outputs a dict with keys:

  • 'raw': BaseMessage
  • 'parsed': None if there was a parsing error, otherwise the type depends on the schema as described above.
  • 'parsing_error': BaseException | None

Behavior changed in 0.3.0

method default changed from "function_calling" to "json_schema".

Behavior changed in 0.3.12

Support for tools added.

Behavior changed in 0.3.21

Pass kwargs through to the model.

Example: schema=Pydantic class, method='json_schema', include_raw=False, strict=True

Note, OpenAI has a number of restrictions on what types of schemas can be provided if strict = True. When using Pydantic, our model cannot specify any Field metadata (like min/max constraints) and fields cannot have default values.

See all constraints here.

from typing import Optional

from langchain_openai import AzureChatOpenAI
from pydantic import BaseModel, Field


class AnswerWithJustification(BaseModel):
    '''An answer to the user question along with justification for the answer.'''

    answer: str
    justification: str | None = Field(
        default=..., description="A justification for the answer."
    )


model = AzureChatOpenAI(
    azure_deployment="...", model="gpt-4o", temperature=0
)
structured_model = model.with_structured_output(AnswerWithJustification)

structured_model.invoke(
    "What weighs more a pound of bricks or a pound of feathers"
)

# -> AnswerWithJustification(
#     answer='They weigh the same',
#     justification='Both a pound of bricks and a pound of feathers weigh one pound. The weight is the same, but the volume or density of the objects may differ.'
# )
Example: schema=Pydantic class, method='function_calling', include_raw=False, strict=False
from typing import Optional

from langchain_openai import AzureChatOpenAI
from pydantic import BaseModel, Field


class AnswerWithJustification(BaseModel):
    '''An answer to the user question along with justification for the answer.'''

    answer: str
    justification: str | None = Field(
        default=..., description="A justification for the answer."
    )


model = AzureChatOpenAI(
    azure_deployment="...", model="gpt-4o", temperature=0
)
structured_model = model.with_structured_output(
    AnswerWithJustification, method="function_calling"
)

structured_model.invoke(
    "What weighs more a pound of bricks or a pound of feathers"
)

# -> AnswerWithJustification(
#     answer='They weigh the same',
#     justification='Both a pound of bricks and a pound of feathers weigh one pound. The weight is the same, but the volume or density of the objects may differ.'
# )
Example: schema=Pydantic class, method='json_schema', include_raw=True
from langchain_openai import AzureChatOpenAI
from pydantic import BaseModel


class AnswerWithJustification(BaseModel):
    '''An answer to the user question along with justification for the answer.'''

    answer: str
    justification: str


model = AzureChatOpenAI(
    azure_deployment="...", model="gpt-4o", temperature=0
)
structured_model = model.with_structured_output(
    AnswerWithJustification, include_raw=True
)

structured_model.invoke(
    "What weighs more a pound of bricks or a pound of feathers"
)
# -> {
#     'raw': AIMessage(content='', additional_kwargs={'tool_calls': [{'id': 'call_Ao02pnFYXD6GN1yzc0uXPsvF', 'function': {'arguments': '{"answer":"They weigh the same.","justification":"Both a pound of bricks and a pound of feathers weigh one pound. The weight is the same, but the volume or density of the objects may differ."}', 'name': 'AnswerWithJustification'}, 'type': 'function'}]}),
#     'parsed': AnswerWithJustification(answer='They weigh the same.', justification='Both a pound of bricks and a pound of feathers weigh one pound. The weight is the same, but the volume or density of the objects may differ.'),
#     'parsing_error': None
# }
Example: schema=TypedDict class, method='json_schema', include_raw=False, strict=False
from typing_extensions import Annotated, TypedDict

from langchain_openai import AzureChatOpenAI


class AnswerWithJustification(TypedDict):
    '''An answer to the user question along with justification for the answer.'''

    answer: str
    justification: Annotated[
        str | None, None, "A justification for the answer."
    ]


model = AzureChatOpenAI(
    azure_deployment="...", model="gpt-4o", temperature=0
)
structured_model = model.with_structured_output(AnswerWithJustification)

structured_model.invoke(
    "What weighs more a pound of bricks or a pound of feathers"
)
# -> {
#     'answer': 'They weigh the same',
#     'justification': 'Both a pound of bricks and a pound of feathers weigh one pound. The weight is the same, but the volume and density of the two substances differ.'
# }
Example: schema=OpenAI function schema, method='json_schema', include_raw=False
from langchain_openai import AzureChatOpenAI

oai_schema = {
    'name': 'AnswerWithJustification',
    'description': 'An answer to the user question along with justification for the answer.',
    'parameters': {
        'type': 'object',
        'properties': {
            'answer': {'type': 'string'},
            'justification': {'description': 'A justification for the answer.', 'type': 'string'}
        },
        'required': ['answer']
    }

    model = AzureChatOpenAI(
        azure_deployment="...",
        model="gpt-4o",
        temperature=0,
    )
    structured_model = model.with_structured_output(oai_schema)

    structured_model.invoke(
        "What weighs more a pound of bricks or a pound of feathers"
    )
    # -> {
    #     'answer': 'They weigh the same',
    #     'justification': 'Both a pound of bricks and a pound of feathers weigh one pound. The weight is the same, but the volume and density of the two substances differ.'
    # }
Example: schema=Pydantic class, method='json_mode', include_raw=True
from langchain_openai import AzureChatOpenAI
from pydantic import BaseModel


class AnswerWithJustification(BaseModel):
    answer: str
    justification: str


model = AzureChatOpenAI(
    azure_deployment="...",
    model="gpt-4o",
    temperature=0,
)
structured_model = model.with_structured_output(
    AnswerWithJustification, method="json_mode", include_raw=True
)

structured_model.invoke(
    "Answer the following question. "
    "Make sure to return a JSON blob with keys 'answer' and 'justification'.\\n\\n"
    "What's heavier a pound of bricks or a pound of feathers?"
)
# -> {
#     'raw': AIMessage(content='{\\n    "answer": "They are both the same weight.",\\n    "justification": "Both a pound of bricks and a pound of feathers weigh one pound. The difference lies in the volume and density of the materials, not the weight." \\n}'),
#     'parsed': AnswerWithJustification(answer='They are both the same weight.', justification='Both a pound of bricks and a pound of feathers weigh one pound. The difference lies in the volume and density of the materials, not the weight.'),
#     'parsing_error': None
# }
Example: schema=None, method='json_mode', include_raw=True
structured_model = model.with_structured_output(
    method="json_mode", include_raw=True
)

structured_model.invoke(
    "Answer the following question. "
    "Make sure to return a JSON blob with keys 'answer' and 'justification'.\\n\\n"
    "What's heavier a pound of bricks or a pound of feathers?"
)
# -> {
#     'raw': AIMessage(content='{\\n    "answer": "They are both the same weight.",\\n    "justification": "Both a pound of bricks and a pound of feathers weigh one pound. The difference lies in the volume and density of the materials, not the weight." \\n}'),
#     'parsed': {
#         'answer': 'They are both the same weight.',
#         'justification': 'Both a pound of bricks and a pound of feathers weigh one pound. The difference lies in the volume and density of the materials, not the weight.'
#     },
#     'parsing_error': None
# }