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ChatWatsonx

Reference docs

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

langchain_ibm.chat_models.ChatWatsonx

Bases: BaseChatModel

IBM watsonx.ai chat models integration.

Setup

To use, you should have langchain_ibm python package installed, and the environment variable WATSONX_API_KEY set with your API key, or pass it as a named parameter api_key to the constructor.

pip install -U langchain-ibm

# or using uv
uv add langchain-ibm
export WATSONX_API_KEY="your-api-key"

Deprecated

apikey and WATSONX_APIKEY are deprecated and will be removed in version 2.0.0. Use api_key and WATSONX_API_KEY instead.

Instantiate

Create a model instance with desired params. For example:

from langchain_ibm import ChatWatsonx
from ibm_watsonx_ai.foundation_models.schema import TextChatParameters

parameters = TextChatParameters(
    top_p=1, temperature=0.5, max_completion_tokens=None
)

model = ChatWatsonx(
    model_id="meta-llama/llama-3-3-70b-instruct",
    url="https://us-south.ml.cloud.ibm.com",
    project_id="*****",
    params=parameters,
    # api_key="*****"
)
Invoke

Generate a response from the model:

messages = [
    (
        "system",
        "You are a helpful translator. Translate the user sentence to French.",
    ),
    ("human", "I love programming."),
]
model.invoke(messages)

Results in an AIMessage response:

AIMessage(
    content="J'adore programmer.",
    additional_kwargs={},
    response_metadata={
        "token_usage": {
            "completion_tokens": 7,
            "prompt_tokens": 30,
            "total_tokens": 37,
        },
        "model_name": "ibm/granite-3-3-8b-instruct",
        "system_fingerprint": "",
        "finish_reason": "stop",
    },
    id="chatcmpl-529352c4-93ba-4801-8f1d-a3b4e3935194---daed91fb74d0405f200db1e63da9a48a---7a3ef799-4413-47e4-b24c-85d267e37fa2",
    usage_metadata={"input_tokens": 30, "output_tokens": 7, "total_tokens": 37},
)
Stream

Stream a response from the model:

for chunk in model.stream(messages):
    print(chunk.text)

Results in a sequence of AIMessageChunk objects with partial content:

AIMessageChunk(content="", id="run--e48a38d3-1500-4b5e-870c-6313e8cff775")
AIMessageChunk(content="J", id="run--e48a38d3-1500-4b5e-870c-6313e8cff775")
AIMessageChunk(content="'", id="run--e48a38d3-1500-4b5e-870c-6313e8cff775")
AIMessageChunk(content="ad", id="run--e48a38d3-1500-4b5e-870c-6313e8cff775")
AIMessageChunk(content="or", id="run--e48a38d3-1500-4b5e-870c-6313e8cff775")
AIMessageChunk(
    content=" programmer", id="run--e48a38d3-1500-4b5e-870c-6313e8cff775"
)
AIMessageChunk(content=".", id="run--e48a38d3-1500-4b5e-870c-6313e8cff775")
AIMessageChunk(
    content="",
    response_metadata={
        "finish_reason": "stop",
        "model_name": "ibm/granite-3-3-8b-instruct",
    },
    id="run--e48a38d3-1500-4b5e-870c-6313e8cff775",
)
AIMessageChunk(
    content="",
    id="run--e48a38d3-1500-4b5e-870c-6313e8cff775",
    usage_metadata={"input_tokens": 30, "output_tokens": 7, "total_tokens": 37},
)

To collect the full message, you can concatenate the chunks:

stream = model.stream(messages)
full = next(stream)
for chunk in stream:
    full += chunk

full
AIMessageChunk(
    content="J'adore programmer.",
    response_metadata={
        "finish_reason": "stop",
        "model_name": "ibm/granite-3-3-8b-instruct",
    },
    id="chatcmpl-88a48b71-c149-4a0c-9c02-d6b97ca5dc6c---b7ba15879a8c5283b1e8a3b8db0229f0---0037ca4f-8a74-4f84-a46c-ab3fd1294f24",
    usage_metadata={"input_tokens": 30, "output_tokens": 7, "total_tokens": 37},
)
Async

Asynchronous equivalents of invoke, stream, and batch are also available:

# Invoke
await model.ainvoke(messages)

# Stream
async for chunk in model.astream(messages):
    print(chunk.text)

# Batch
await model.abatch([messages])

Results in an AIMessage response:

AIMessage(
    content="J'adore programmer.",
    additional_kwargs={},
    response_metadata={
        "token_usage": {
            "completion_tokens": 7,
            "prompt_tokens": 30,
            "total_tokens": 37,
        },
        "model_name": "ibm/granite-3-3-8b-instruct",
        "system_fingerprint": "",
        "finish_reason": "stop",
    },
    id="chatcmpl-5bef2d81-ef56-463b-a8fa-c2bcc2a3c348---821e7750d18925f2b36226db66667e26---6396c786-9da9-4468-883e-11ed90a05937",
    usage_metadata={"input_tokens": 30, "output_tokens": 7, "total_tokens": 37},
)

For batched calls, results in a list[AIMessage].

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]
    # strict = True  # Enforce tool args schema is respected
)
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": "chatcmpl-tool-59632abcee8f48a18a5f3a81422b917b",
        "type": "tool_call",
    },
    {
        "name": "GetWeather",
        "args": {"location": "New York, NY"},
        "id": "chatcmpl-tool-c6f3b033b4594918bb53f656525b0979",
        "type": "tool_call",
    },
    {
        "name": "GetPopulation",
        "args": {"location": "Los Angeles, CA"},
        "id": "chatcmpl-tool-175a23281e4747ea81cbe472b8e47012",
        "type": "tool_call",
    },
    {
        "name": "GetPopulation",
        "args": {"location": "New York, NY"},
        "id": "chatcmpl-tool-e1ccc534835945aebab708eb5e685bf7",
        "type": "tool_call",
    },
]
Reasoning output
from langchain_ibm import ChatWatsonx
from ibm_watsonx_ai.foundation_models.schema import TextChatParameters

parameters = TextChatParameters(
    include_reasoning=True, reasoning_effort="medium"
)

model = ChatWatsonx(
    model_id="openai/gpt-oss-120b",
    url="https://us-south.ml.cloud.ibm.com",
    project_id="*****",
    params=parameters,
    # api_key="*****"
)

response = model.invoke("What is 3^3?")

# Response text
print(f"Output: {response.content}")

# Reasoning summaries
print(f"Reasoning: {response.additional_kwargs['reasoning_content']}")
Output: 3^3 = 27
Reasoning: The user asks "What is 3^3?" That's 27. Provide answer.

Added in version 0.3.19: Updated AIMessage format

langchain-ibm >= 0.3.19 allows users to set Reasoning output parameters and will format output from reasoning summaries into additional_kwargs field.

Structured output
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, 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 with_structured_output for more info.

JSON mode
json_model = model.bind(response_format={"type": "json_object"})
ai_msg = json_model.invoke(
    Return JSON with 'random_ints': an array of 10 random integers from 0-99.
)
ai_msg.content
'{\n  "random_ints": [12, 34, 56, 78, 10, 22, 44, 66, 88, 99]\n}'
Image input
import base64
import httpx
from langchain.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 presents a clear, sunny day with good visibility
and no immediate signs of rain or strong winds. The vibrant blue sky with
scattered white clouds gives the impression of a tranquil, pleasant day
conducive to outdoor activities."
Token usage
ai_msg = model.invoke(messages)
ai_msg.usage_metadata
{'input_tokens': 30, 'output_tokens': 7, 'total_tokens': 37}
stream = model.stream(messages)
full = next(stream)
for chunk in stream:
    full += chunk
full.usage_metadata
{'input_tokens': 30, 'output_tokens': 7, 'total_tokens': 37}
Logprobs
logprobs_model = model.bind(logprobs=True)
ai_msg = logprobs_model.invoke(messages)
ai_msg.response_metadata["logprobs"]
{
    'content': [
        {
            'token': 'J',
            'logprob': -0.0017940393
        },
        {
            'token': "'",
            'logprob': -1.7523613e-05
        },
        {
            'token': 'ad',
            'logprob': -0.16112353
        },
        {
            'token': 'ore',
            'logprob': -0.0003091811
        },
        {
            'token': ' programmer',
            'logprob': -0.24849245
        },
        {
            'token': '.',
            'logprob': -2.5033638e-05
        },
        {
            'token': '<|end_of_text|>',
            'logprob': -7.080781e-05
        }
    ]
}
Response metadata
ai_msg = model.invoke(messages)
ai_msg.response_metadata
{
    'token_usage': {
        'completion_tokens': 7,
        'prompt_tokens': 30,
        'total_tokens': 37
    },
    'model_name': 'ibm/granite-3-3-8b-instruct',
    'system_fingerprint': '',
    'finish_reason': 'stop'
}
METHOD DESCRIPTION
is_lc_serializable

Is lc serializable.

validate_environment

Validate that credentials and python package exists in environment.

bind_tools

Bind tool-like objects to this chat model.

with_structured_output

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

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__
get_lc_namespace

Get the namespace of the LangChain object.

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

Return the ordered IDs of the tokens in a text.

get_num_tokens

Get the number of tokens present in the text.

get_num_tokens_from_messages

Get the number of tokens in the messages.

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.

model_id class-attribute instance-attribute

model_id: str | None = None

Type of model to use.

model class-attribute instance-attribute

model: str | None = None

Name or alias of the foundation model to use. When using IBM's watsonx.ai Model Gateway (public preview), you can specify any supported third-party model—OpenAI, Anthropic, NVIDIA, Cerebras, or IBM's own Granite series—via a single, OpenAI-compatible interface. Models must be explicitly provisioned (opt-in) through the Gateway to ensure secure, vendor-agnostic access and easy switch-over without reconfiguration.

For more details on configuration and usage, see IBM watsonx Model Gateway docs

deployment_id class-attribute instance-attribute

deployment_id: str | None = None

Type of deployed model to use.

project_id class-attribute instance-attribute

project_id: str | None = None

ID of the Watson Studio project.

space_id class-attribute instance-attribute

space_id: str | None = None

ID of the Watson Studio space.

url class-attribute instance-attribute

url: SecretStr = Field(
    alias="url", default_factory=secret_from_env("WATSONX_URL", default=None)
)

URL to the Watson Machine Learning or CPD instance.

api_key class-attribute instance-attribute

api_key: SecretStr | None = Field(
    default_factory=secret_from_env_multi(
        names_priority=["WATSONX_API_KEY", "WATSONX_APIKEY"],
        deprecated={"WATSONX_APIKEY"},
    ),
    serialization_alias="api_key",
    validation_alias=AliasChoices("api_key", "apikey"),
    description="API key to the Watson Machine Learning or CPD instance.",
)

API key to the Watson Machine Learning or CPD instance.

token class-attribute instance-attribute

token: SecretStr | None = Field(
    alias="token", default_factory=secret_from_env("WATSONX_TOKEN", default=None)
)

Token to the CPD instance.

password class-attribute instance-attribute

password: SecretStr | None = Field(
    alias="password", default_factory=secret_from_env("WATSONX_PASSWORD", default=None)
)

Password to the CPD instance.

username class-attribute instance-attribute

username: SecretStr | None = Field(
    alias="username", default_factory=secret_from_env("WATSONX_USERNAME", default=None)
)

Username to the CPD instance.

instance_id class-attribute instance-attribute

instance_id: SecretStr | None = Field(
    alias="instance_id",
    default_factory=secret_from_env("WATSONX_INSTANCE_ID", default=None),
)

Instance_id of the CPD instance.

version class-attribute instance-attribute

version: SecretStr | None = None

Version of the CPD instance.

params class-attribute instance-attribute

params: dict | TextChatParameters | None = None

Model parameters to use during request generation.

Note

ValueError is raised if the same Chat generation parameter is provided within the params attribute and as keyword argument.

frequency_penalty class-attribute instance-attribute

frequency_penalty: float | None = None

Positive values penalize new tokens based on their existing frequency in the text so far, decreasing the model's likelihood to repeat the same line verbatim.

logprobs class-attribute instance-attribute

logprobs: bool | None = None

Whether to return log probabilities of the output tokens or not. If true, returns the log probabilities of each output token returned in the content of message.

top_logprobs class-attribute instance-attribute

top_logprobs: int | None = None

An integer specifying the number of most likely tokens to return at each token position, each with an associated log probability. The option logprobs must be set to true if this parameter is used.

max_tokens class-attribute instance-attribute

max_tokens: int | None = None

The maximum number of tokens that can be generated in the chat completion. The total length of input tokens and generated tokens is limited by the model's context length. This value is now deprecated in favor of 'max_completion_tokens' parameter.

max_completion_tokens class-attribute instance-attribute

max_completion_tokens: int | None = None

The maximum number of tokens that can be generated in the chat completion. The total length of input tokens and generated tokens is limited by the model's context length.

n class-attribute instance-attribute

n: int | None = None

How many chat completion choices to generate for each input message. Note that you will be charged based on the number of generated tokens across all of the choices. Keep n as 1 to minimize costs.

presence_penalty class-attribute instance-attribute

presence_penalty: float | None = None

Positive values penalize new tokens based on whether they appear in the text so far, increasing the model's likelihood to talk about new topics.

temperature class-attribute instance-attribute

temperature: float | None = None

What sampling temperature to use. Higher values like 0.8 will make the output more random, while lower values like 0.2 will make it more focused and deterministic.

We generally recommend altering this or top_p but not both.

response_format class-attribute instance-attribute

response_format: dict | None = None

The chat response format parameters.

top_p class-attribute instance-attribute

top_p: float | None = None

An alternative to sampling with temperature, called nucleus sampling, where the model considers the results of the tokens with top_p probability mass. So 0.1 means only the tokens comprising the top 10% probability mass are considered.

We generally recommend altering this or temperature but not both.

time_limit class-attribute instance-attribute

time_limit: int | None = None

Time limit in milliseconds - if not completed within this time, generation will stop.

logit_bias class-attribute instance-attribute

logit_bias: dict | None = None

Increasing or decreasing probability of tokens being selected during generation.

seed class-attribute instance-attribute

seed: int | None = None

Random number generator seed to use in sampling mode for experimental repeatability.

stop class-attribute instance-attribute

stop: list[str] | None = None

Stop sequences are one or more strings which will cause the text generation to stop if/when they are produced as part of the output.

chat_template_kwargs class-attribute instance-attribute

chat_template_kwargs: dict | None = None

Additional chat template parameters.

verify class-attribute instance-attribute

verify: str | bool | None = None

You can pass one of following as verify: * the path to a CA_BUNDLE file * the path of directory with certificates of trusted CAs * True - default path to truststore will be taken * False - no verification will be made

validate_model class-attribute instance-attribute

validate_model: bool = True

Model ID validation.

streaming class-attribute instance-attribute

streaming: bool = False

Whether to stream the results or not.

lc_secrets property

lc_secrets: dict[str, str]

Mapping of secret environment variables.

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.

lc_attributes property

lc_attributes: dict

List of attribute names that should be included in the serialized kwargs.

These attributes must be accepted by the constructor.

Default is an empty dictionary.

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 store in message content.

AIMessage.content_blocks will lazily parse the contents of content into a standard format. This flag can be used to additionally store the standard format in message content, e.g., for serialization purposes.

Supported values:

  • 'v0': provider-specific format in content (can lazily-parse with content_blocks)
  • 'v1': standardized format in content (consistent with content_blocks)

Partner packages (e.g., langchain-openai) can also use this field to roll out new content formats in a backward-compatible way.

Added in langchain-core 1.0

profile property

profile: ModelProfile

Return profiling information for the model.

This property relies on the langchain-model-profiles package to retrieve chat model capabilities, such as context window sizes and supported features.

RAISES DESCRIPTION
ImportError

If langchain-model-profiles is not installed.

RETURNS DESCRIPTION
ModelProfile

A ModelProfile object containing profiling information for the model.

is_lc_serializable classmethod

is_lc_serializable() -> bool

Is lc serializable.

validate_environment

validate_environment() -> Self

Validate that credentials and python package exists in environment.

bind_tools

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

Bind tool-like objects to this chat model.

PARAMETER DESCRIPTION
tools

A list of tool definitions to bind to this chat model. Can be a dictionary, pydantic model, callable, or BaseTool. Pydantic models, callables, and BaseTools will be automatically converted to their schema dictionary representation.

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

kwargs

Any additional parameters are passed directly to bind.

TYPE: Any DEFAULT: {}

with_structured_output

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

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,
  • or a Pydantic class,

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.

TYPE: dict | type | None DEFAULT: None

method

The method for steering model generation, one of:

  • 'function_calling': uses tool-calling features.
  • 'json_schema': uses dedicated structured output features.
  • 'json_mode': uses JSON mode.

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

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.

TYPE: bool | None DEFAULT: None

kwargs

Additional keyword args

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
Runnable[LanguageModelInput, dict | BaseModel]

A Runnable that takes same inputs as a langchain_core.language_models.chat.BaseChatModel.

Runnable[LanguageModelInput, dict | BaseModel]

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

Runnable[LanguageModelInput, dict | BaseModel]
  • 'raw': BaseMessage
Runnable[LanguageModelInput, dict | BaseModel]
  • 'parsed': None if there was a parsing error, otherwise the type depends on the schema as described above.
Runnable[LanguageModelInput, dict | BaseModel]
  • 'parsing_error': Optional[BaseException]
Example: schema=Pydantic class, method='function_calling', include_raw=True
from langchain_ibm import ChatWatsonx
from pydantic import BaseModel


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

    answer: str
    justification: str


model = ChatWatsonx(...)
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=JSON schema, method='function_calling', include_raw=False
from langchain_ibm import ChatWatsonx
from pydantic import BaseModel
from langchain_core.utils.function_calling import convert_to_openai_tool


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

    answer: str
    justification: str


dict_schema = convert_to_openai_tool(AnswerWithJustification)
model = ChatWatsonx(...)
structured_model = model.with_structured_output(dict_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_schema', include_raw=True
from langchain_ibm import ChatWatsonx
from pydantic import BaseModel


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

    answer: str
    justification: str


model = ChatWatsonx(...)
structured_model = model.with_structured_output(
    AnswerWithJustification, method="json_schema", 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": "chatcmpl-tool-bfbd6f6dd33b438990c5ddf277485971",
                    "type": "function",
                    "function": {
                        "name": "AnswerWithJustification",
                        "arguments": '{"answer": "They weigh the same", "justification": "A pound is a unit of weight or mass, so both a pound of bricks and a pound of feathers weigh the same amount, one pound."}',
                    },
                }
            ]
        },
        response_metadata={
            "token_usage": {
                "completion_tokens": 45,
                "prompt_tokens": 275,
                "total_tokens": 320,
            },
            "model_name": "meta-llama/llama-3-3-70b-instruct",
            "system_fingerprint": "",
            "finish_reason": "stop",
        },
        id="chatcmpl-461ca5bd-1982-412c-b886-017c483bf481---8c18b06eead65ae4691364798787bda7---71896588-efa5-439f-a25f-d1abfe289f5a",
        tool_calls=[
            {
                "name": "AnswerWithJustification",
                "args": {
                    "answer": "They weigh the same",
                    "justification": "A pound is a unit of weight or mass, so both a pound of bricks and a pound of feathers weigh the same amount, one pound.",
                },
                "id": "chatcmpl-tool-bfbd6f6dd33b438990c5ddf277485971",
                "type": "tool_call",
            }
        ],
        usage_metadata={
            "input_tokens": 275,
            "output_tokens": 45,
            "total_tokens": 320,
        },
    ),
    "parsed": AnswerWithJustification(
        answer="They weigh the same",
        justification="A pound is a unit of weight or mass, so both a pound of bricks and a pound of feathers weigh the same amount, one pound.",
    ),
    "parsing_error": None,
}
Example: schema=function schema, method='json_schema', include_raw=False
from langchain_ibm import ChatWatsonx
from pydantic import BaseModel

function__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 = ChatWatsonx(...)
structured_model = model.with_structured_output(
    function_schema, method="json_schema", include_raw=False
)

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_ibm import ChatWatsonx
from pydantic import BaseModel


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


model = ChatWatsonx(...)
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
from langchain_ibm import ChatWatsonx

model = ChatWatsonx(...)
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,
}

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 langchain-core 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 langchain-core 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 langchain-core 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_core.language_models.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 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 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 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 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 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 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]})

str 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")

__init__

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

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

For example, if the class is langchain.llms.openai.OpenAI, then the namespace is ["langchain", "llms", "openai"]

RETURNS DESCRIPTION
list[str]

The namespace.

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-sonnet-4-5-20250929"
).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]

Return the ordered IDs of the tokens in a text.

PARAMETER DESCRIPTION
text

The string input to tokenize.

TYPE: str

RETURNS DESCRIPTION
list[int]

A list of IDs corresponding to the tokens in the text, in order they occur in the text.

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: list[BaseMessage], tools: Sequence | None = None
) -> int

Get the number of tokens in the messages.

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

Note

The base implementation of get_num_tokens_from_messages ignores tool schemas.

PARAMETER DESCRIPTION
messages

The message inputs to tokenize.

TYPE: list[BaseMessage]

tools

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

TYPE: Sequence | None DEFAULT: None

RETURNS DESCRIPTION
int

The sum of the number of tokens across the messages.

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.