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ChatAnthropic

Reference docs

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

langchain_anthropic.chat_models.ChatAnthropic

Bases: BaseChatModel

Anthropic chat models.

See Anthropic's docs for a list of the latest models.

Setup

Install langchain-anthropic and set environment variable ANTHROPIC_API_KEY.

pip install -U langchain-anthropic
export ANTHROPIC_API_KEY="your-api-key"

Key init args — completion params: model: Name of Anthropic model to use. e.g. 'claude-3-7-sonnet-20250219'. temperature: Sampling temperature. Ranges from 0.0 to 1.0. max_tokens: Max number of tokens to generate.

Key init args — client params: timeout: Timeout for requests. anthropic_proxy: Proxy to use for the Anthropic clients, will be used for every API call. If not passed in will be read from env var ANTHROPIC_PROXY. max_retries: Max number of retries if a request fails. api_key: Anthropic API key. If not passed in will be read from env var ANTHROPIC_API_KEY. base_url: Base URL for API requests. Only specify if using a proxy or service emulator.

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

Instantiate
from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(
    model="claude-3-7-sonnet-20250219",
    temperature=0,
    max_tokens=1024,
    timeout=None,
    max_retries=2,
    # api_key="...",
    # base_url="...",
    # other params...
)

Note

Any param which is not explicitly supported will be passed directly to the anthropic.Anthropic.messages.create(...) API every time to the model is invoked. For example:

from langchain_anthropic import ChatAnthropic
import anthropic

ChatAnthropic(..., extra_headers={}).invoke(...)

# results in underlying API call of:

anthropic.Anthropic(..).messages.create(..., extra_headers={})

# which is also equivalent to:

ChatAnthropic(...).invoke(..., extra_headers={})
Invoke
messages = [
    (
        "system",
        "You are a helpful translator. Translate the user sentence to French.",
    ),
    ("human", "I love programming."),
]
model.invoke(messages)
AIMessage(
    content="J'aime la programmation.",
    response_metadata={
        "id": "msg_01Trik66aiQ9Z1higrD5XFx3",
        "model": "claude-3-7-sonnet-20250219",
        "stop_reason": "end_turn",
        "stop_sequence": None,
        "usage": {"input_tokens": 25, "output_tokens": 11},
    },
    id="run-5886ac5f-3c2e-49f5-8a44-b1e92808c929-0",
    usage_metadata={
        "input_tokens": 25,
        "output_tokens": 11,
        "total_tokens": 36,
    },
)
Stream
for chunk in model.stream(messages):
    print(chunk.text, end="")
AIMessageChunk(content="J", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
AIMessageChunk(content="'", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
AIMessageChunk(content="a", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
AIMessageChunk(content="ime", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
AIMessageChunk(content=" la", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
AIMessageChunk(content=" programm", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
AIMessageChunk(content="ation", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
AIMessageChunk(content=".", id="run-272ff5f9-8485-402c-b90d-eac8babc5b25")
stream = model.stream(messages)
full = next(stream)
for chunk in stream:
    full += chunk
full
AIMessageChunk(content="J'aime la programmation.", id="run-b34faef0-882f-4869-a19c-ed2b856e6361")
Async
await model.ainvoke(messages)

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

# batch:
# await model.abatch([messages])
AIMessage(
    content="J'aime la programmation.",
    response_metadata={
        "id": "msg_01Trik66aiQ9Z1higrD5XFx3",
        "model": "claude-3-7-sonnet-20250219",
        "stop_reason": "end_turn",
        "stop_sequence": None,
        "usage": {"input_tokens": 25, "output_tokens": 11},
    },
    id="run-5886ac5f-3c2e-49f5-8a44-b1e92808c929-0",
    usage_metadata={
        "input_tokens": 25,
        "output_tokens": 11,
        "total_tokens": 36,
    },
)
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": "toolu_01KzpPEAgzura7hpBqwHbWdo",
    },
    {
        "name": "GetWeather",
        "args": {"location": "New York, NY"},
        "id": "toolu_01JtgbVGVJbiSwtZk3Uycezx",
    },
    {
        "name": "GetPopulation",
        "args": {"location": "Los Angeles, CA"},
        "id": "toolu_01429aygngesudV9nTbCKGuw",
    },
    {
        "name": "GetPopulation",
        "args": {"location": "New York, NY"},
        "id": "toolu_01JPktyd44tVMeBcPPnFSEJG",
    },
]

See ChatAnthropic.bind_tools() method for more.

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 ChatAnthropic.with_structured_output() for more.

Image input

See multimodal guides for more detail.

import base64

import httpx
from langchain_anthropic import ChatAnthropic
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")

model = ChatAnthropic(model="claude-3-5-sonnet-latest")
message = HumanMessage(
    content=[
        {
            "type": "text",
            "text": "Can you highlight the differences between these two images?",
        },
        {
            "type": "image",
            "base64": image_data,
            "mime_type": "image/jpeg",
        },
        {
            "type": "image",
            "url": image_url,
        },
    ],
)
ai_msg = model.invoke([message])
ai_msg.content
"After examining both images carefully, I can see that they are actually identical."
Files API

You can also pass in files that are managed through Anthropic's Files API:

from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(
    model="claude-sonnet-4-20250514",
    betas=["files-api-2025-04-14"],
)
input_message = {
    "role": "user",
    "content": [
        {
            "type": "text",
            "text": "Describe this document.",
        },
        {
            "type": "image",
            "id": "file_abc123...",
        },
    ],
}
model.invoke([input_message])
PDF input

See multimodal guides for more detail.

from base64 import b64encode
from langchain_anthropic import ChatAnthropic
from langchain_core.messages import HumanMessage
import requests

url = "https://www.w3.org/WAI/ER/tests/xhtml/testfiles/resources/pdf/dummy.pdf"
data = b64encode(requests.get(url).content).decode()

model = ChatAnthropic(model="claude-3-5-sonnet-latest")
ai_msg = model.invoke(
    [
        HumanMessage(
            [
                "Summarize this document.",
                {
                    "type": "file",
                    "mime_type": "application/pdf",
                    "base64": data,
                },
            ]
        )
    ]
)
ai_msg.content
"This appears to be a simple document..."
Files API

You can also pass in files that are managed through Anthropic's Files API:

from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(
    model="claude-sonnet-4-20250514",
    betas=["files-api-2025-04-14"],
)
input_message = {
    "role": "user",
    "content": [
        {
            "type": "text",
            "text": "Describe this document.",
        },
        {
            "type": "file",
            "id": "file_abc123...",
        },
    ],
}
model.invoke([input_message])
Extended thinking

Certain Claude models support an extended thinking feature, which will output the step-by-step reasoning process that led to its final answer.

To use it, specify the thinking parameter when initializing ChatAnthropic.

It can also be passed in as a kwarg during invocation.

You will need to specify a token budget to use this feature. See usage example:

from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(
    model="claude-3-7-sonnet-latest",
    max_tokens=5000,
    thinking={"type": "enabled", "budget_tokens": 2000},
)

response = model.invoke("What is the cube root of 50.653?")
response.content
[
    {
        "signature": "...",
        "thinking": "To find the cube root of 50.653...",
        "type": "thinking",
    },
    {"text": "The cube root of 50.653 is ...", "type": "text"},
]

Differences in thinking across model versions

The Claude Messages API handles thinking differently across Claude Sonnet 3.7 and Claude 4 models. Refer to their docs for more info.

Citations

Anthropic supports a citations feature that lets Claude attach context to its answers based on source documents supplied by the user. When document content blocks with "citations": {"enabled": True} are included in a query, Claude may generate citations in its response.

from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(model="claude-3-5-haiku-latest")

messages = [
    {
        "role": "user",
        "content": [
            {
                "type": "document",
                "source": {
                    "type": "text",
                    "media_type": "text/plain",
                    "data": "The grass is green. The sky is blue.",
                },
                "title": "My Document",
                "context": "This is a trustworthy document.",
                "citations": {"enabled": True},
            },
            {"type": "text", "text": "What color is the grass and sky?"},
        ],
    }
]
response = model.invoke(messages)
response.content
[
    {"text": "Based on the document, ", "type": "text"},
    {
        "text": "the grass is green",
        "type": "text",
        "citations": [
            {
                "type": "char_location",
                "cited_text": "The grass is green. ",
                "document_index": 0,
                "document_title": "My Document",
                "start_char_index": 0,
                "end_char_index": 20,
            }
        ],
    },
    {"text": ", and ", "type": "text"},
    {
        "text": "the sky is blue",
        "type": "text",
        "citations": [
            {
                "type": "char_location",
                "cited_text": "The sky is blue.",
                "document_index": 0,
                "document_title": "My Document",
                "start_char_index": 20,
                "end_char_index": 36,
            }
        ],
    },
    {"text": ".", "type": "text"},
]
Token usage
ai_msg = model.invoke(messages)
ai_msg.usage_metadata
{"input_tokens": 25, "output_tokens": 11, "total_tokens": 36}

Message chunks containing token usage will be included during streaming by default:

stream = model.stream(messages)
full = next(stream)
for chunk in stream:
    full += chunk
full.usage_metadata
{"input_tokens": 25, "output_tokens": 11, "total_tokens": 36}

These can be disabled by setting stream_usage=False in the stream method, or by setting stream_usage=False when initializing ChatAnthropic.

Prompt caching

Prompt caching reduces processing time and costs for repetitive tasks or prompts with consistent elements

Note

Only certain models support prompt caching. See the Claude documentation for a full list.

from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(model="claude-3-7-sonnet-20250219")

messages = [
    {
        "role": "system",
        "content": [
            {
                "type": "text",
                "text": "Below is some long context:",
            },
            {
                "type": "text",
                "text": f"{long_text}",
                "cache_control": {"type": "ephemeral"},
            },
        ],
    },
    {
        "role": "user",
        "content": "What's that about?",
    },
]

response = model.invoke(messages)
response.usage_metadata["input_token_details"]
{"cache_read": 0, "cache_creation": 1458}

Alternatively, you may enable prompt caching at invocation time. You may want to conditionally cache based on runtime conditions, such as the length of the context. Alternatively, this is useful for app-level decisions about what to cache.

response = model.invoke(
    messages,
    cache_control={"type": "ephemeral"},
)
Extended caching

The cache lifetime is 5 minutes by default. If this is too short, you can apply one hour caching by setting ttl to '1h'.

model = ChatAnthropic(
    model="claude-3-7-sonnet-20250219",
)

messages = [
    {
        "role": "user",
        "content": [
            {
                "type": "text",
                "text": f"{long_text}",
                "cache_control": {"type": "ephemeral", "ttl": "1h"},
            },
        ],
    }
]

response = model.invoke(messages)

Details of cached token counts will be included on the InputTokenDetails of response's usage_metadata:

response = model.invoke(messages)
response.usage_metadata
{
    "input_tokens": 1500,
    "output_tokens": 200,
    "total_tokens": 1700,
    "input_token_details": {
        "cache_read": 0,
        "cache_creation": 1000,
        "ephemeral_1h_input_tokens": 750,
        "ephemeral_5m_input_tokens": 250,
    },
}

See Claude documentation for detail.

!!! note title="Extended context windows (beta)"

Claude Sonnet 4 supports a 1-million token context window, available in beta for
organizations in usage tier 4 and organizations with custom rate limits.

```python
from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(
    model="claude-sonnet-4-20250514",
    betas=["context-1m-2025-08-07"],  # Enable 1M context beta
)

long_document = """
This is a very long document that would benefit from the extended 1M
context window...
[imagine this continues for hundreds of thousands of tokens]
"""

messages = [
    HumanMessage(f"""
Please analyze this document and provide a summary:

{long_document}

What are the key themes and main conclusions?
""")
]

response = model.invoke(messages)
```

See [Claude documentation](https://docs.claude.com/en/docs/build-with-claude/context-windows#1m-token-context-window)
for detail.

!!! note title="Token-efficient tool use (beta)"

See LangChain [docs](https://python.langchain.com/docs/integrations/chat/anthropic/)
for more detail.

```python
from langchain_anthropic import ChatAnthropic
from langchain_core.tools import tool

model = ChatAnthropic(
    model="claude-3-7-sonnet-20250219",
    temperature=0,
    model_kwargs={
        "extra_headers": {
            "anthropic-beta": "token-efficient-tools-2025-02-19"
        }
    }
)

@tool
def get_weather(location: str) -> str:
    """Get the weather at a location."""
    return "It's sunny."

model_with_tools = model.bind_tools([get_weather])
response = model_with_tools.invoke(
    "What's the weather in San Francisco?"
)
print(response.tool_calls)
print(f'Total tokens: {response.usage_metadata["total_tokens"]}')
```

```txt
[{'name': 'get_weather', 'args': {'location': 'San Francisco'}, 'id': 'toolu_01HLjQMSb1nWmgevQUtEyz17', 'type': 'tool_call'}]
Total tokens: 408
```

!!! note title="Context management"

Anthropic supports a context editing feature that will automatically manage the
model's context window (e.g., by clearing tool results).

See [Anthropic documentation](https://docs.claude.com/en/docs/build-with-claude/context-editing)
for details and configuration options.

```python
from langchain_anthropic import ChatAnthropic

model = ChatAnthropic(
    model="claude-sonnet-4-5",
    betas=["context-management-2025-06-27"],
    context_management={"edits": [{"type": "clear_tool_uses_20250919"}]},
)
model_with_tools = model.bind_tools([{"type": "web_search_20250305", "name": "web_search"}])
response = model_with_tools.invoke("Search for recent developments in AI")
```

!!! note title="Built-in tools"

See LangChain [docs](https://python.langchain.com/docs/integrations/chat/anthropic/#built-in-tools)
for more detail.

??? note "Web search"

    ```python
    from langchain_anthropic import ChatAnthropic

    model = ChatAnthropic(model="claude-3-5-haiku-latest")

    tool = {
        "type": "web_search_20250305",
        "name": "web_search",
        "max_uses": 3,
    }
    model_with_tools = model.bind_tools([tool])

    response = model_with_tools.invoke("How do I update a web app to TypeScript 5.5?")
    ```

??? note "Web fetch (beta)"

    ```python
    from langchain_anthropic import ChatAnthropic

    model = ChatAnthropic(
        model="claude-3-5-haiku-latest",
        betas=["web-fetch-2025-09-10"],  # Enable web fetch beta
    )

    tool = {
        "type": "web_fetch_20250910",
        "name": "web_fetch",
        "max_uses": 3,
    }
    model_with_tools = model.bind_tools([tool])

    response = model_with_tools.invoke("Please analyze the content at https://example.com/article")
    ```

??? note "Code execution"

    ```python
    model = ChatAnthropic(
        model="claude-sonnet-4-20250514",
        betas=["code-execution-2025-05-22"],
    )

    tool = {"type": "code_execution_20250522", "name": "code_execution"}
    model_with_tools = model.bind_tools([tool])

    response = model_with_tools.invoke(
        "Calculate the mean and standard deviation of [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]"
    )
    ```

??? note "Remote MCP"

    ```python
    from langchain_anthropic import ChatAnthropic

    mcp_servers = [
        {
            "type": "url",
            "url": "https://mcp.deepwiki.com/mcp",
            "name": "deepwiki",
            "tool_configuration": {  # optional configuration
                "enabled": True,
                "allowed_tools": ["ask_question"],
            },
            "authorization_token": "PLACEHOLDER",  # optional authorization
        }
    ]

    model = ChatAnthropic(
        model="claude-sonnet-4-20250514",
        betas=["mcp-client-2025-04-04"],
        mcp_servers=mcp_servers,
    )

    response = model.invoke(
        "What transport protocols does the 2025-03-26 version of the MCP "
        "spec (modelcontextprotocol/modelcontextprotocol) support?"
    )
    ```

??? note "Text editor"

    ```python
    from langchain_anthropic import ChatAnthropic

    model = ChatAnthropic(model="claude-3-7-sonnet-20250219")

    tool = {"type": "text_editor_20250124", "name": "str_replace_editor"}
    model_with_tools = model.bind_tools([tool])

    response = model_with_tools.invoke(
        "There's a syntax error in my primes.py file. Can you help me fix it?"
    )
    print(response.text)
    response.tool_calls
    ```

    ```txt
    I'd be happy to help you fix the syntax error in your primes.py file. First, let's look at the current content of the file to identify the error.

    [{'name': 'str_replace_editor',
    'args': {'command': 'view', 'path': '/repo/primes.py'},
    'id': 'toolu_01VdNgt1YV7kGfj9LFLm6HyQ',
    'type': 'tool_call'}]
    ```

??? note "Memory tool"

    ```python
    from langchain_anthropic import ChatAnthropic

    model = ChatAnthropic(
        model="claude-sonnet-4-5",
        betas=["context-management-2025-06-27"],
    )
    model_with_tools = model.bind_tools([{"type": "memory_20250818", "name": "memory"}])
    response = model_with_tools.invoke("What are my interests?")
    ```

!!! note title="Response metadata"

```python
ai_msg = model.invoke(messages)
ai_msg.response_metadata
```

```python
{
    "id": "msg_013xU6FHEGEq76aP4RgFerVT",
    "model": "claude-3-7-sonnet-20250219",
    "stop_reason": "end_turn",
    "stop_sequence": None,
    "usage": {"input_tokens": 25, "output_tokens": 11},
}
```
METHOD DESCRIPTION
is_lc_serializable

Whether the class is serializable in langchain.

get_lc_namespace

Get the namespace of the LangChain object.

set_default_max_tokens

Set default max_tokens.

build_extra

Build model kwargs.

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_num_tokens_from_messages

Count tokens in a sequence of input messages.

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

Return the ordered ids of the tokens in a text.

get_num_tokens

Get the number of tokens present in the text.

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 class-attribute instance-attribute

model: str = Field(alias='model_name')

Model name to use.

max_tokens class-attribute instance-attribute

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

Denotes the number of tokens to predict per generation.

temperature class-attribute instance-attribute

temperature: float | None = None

A non-negative float that tunes the degree of randomness in generation.

top_k class-attribute instance-attribute

top_k: int | None = None

Number of most likely tokens to consider at each step.

top_p class-attribute instance-attribute

top_p: float | None = None

Total probability mass of tokens to consider at each step.

default_request_timeout class-attribute instance-attribute

default_request_timeout: float | None = Field(None, alias='timeout')

Timeout for requests to Anthropic Completion API.

max_retries class-attribute instance-attribute

max_retries: int = 2

Number of retries allowed for requests sent to the Anthropic Completion API.

stop_sequences class-attribute instance-attribute

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

Default stop sequences.

anthropic_api_url class-attribute instance-attribute

anthropic_api_url: str | None = Field(
    alias="base_url",
    default_factory=from_env(
        ["ANTHROPIC_API_URL", "ANTHROPIC_BASE_URL"], default="https://api.anthropic.com"
    ),
)

Base URL for API requests. Only specify if using a proxy or service emulator.

If a value isn't passed in, will attempt to read the value first from ANTHROPIC_API_URL and if that is not set, ANTHROPIC_BASE_URL. If neither are set, the default value of https://api.anthropic.com will be used.

anthropic_api_key class-attribute instance-attribute

anthropic_api_key: SecretStr = Field(
    alias="api_key", default_factory=secret_from_env("ANTHROPIC_API_KEY", default="")
)

Automatically read from env var ANTHROPIC_API_KEY if not provided.

anthropic_proxy class-attribute instance-attribute

anthropic_proxy: str | None = Field(
    default_factory=from_env("ANTHROPIC_PROXY", default=None)
)

Proxy to use for the Anthropic clients, will be used for every API call.

If not provided, will attempt to read from the ANTHROPIC_PROXY environment variable.

default_headers class-attribute instance-attribute

default_headers: Mapping[str, str] | None = None

Headers to pass to the Anthropic clients, will be used for every API call.

betas class-attribute instance-attribute

betas: list[str] | None = None

List of beta features to enable. If specified, invocations will be routed through client.beta.messages.create.

Example: betas=["mcp-client-2025-04-04"]

streaming class-attribute instance-attribute

streaming: bool = False

Whether to use streaming or not.

stream_usage class-attribute instance-attribute

stream_usage: bool = True

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

thinking class-attribute instance-attribute

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

Parameters for Claude reasoning, e.g., {"type": "enabled", "budget_tokens": 10_000}

mcp_servers class-attribute instance-attribute

mcp_servers: list[dict[str, Any]] | None = None

List of MCP servers to use for the request.

Example: mcp_servers=[{"type": "url", "url": "https://mcp.example.com/mcp", "name": "example-mcp"}]

context_management class-attribute instance-attribute

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

Configuration for context management.

lc_secrets property

lc_secrets: dict[str, str]

Return a mapping of secret keys to 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 version 1.0

is_lc_serializable classmethod

is_lc_serializable() -> bool

Whether the class is serializable in langchain.

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

set_default_max_tokens classmethod

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

Set default max_tokens.

build_extra classmethod

build_extra(values: dict) -> Any

Build model kwargs.

bind_tools

bind_tools(
    tools: Sequence[dict[str, Any] | type | Callable | BaseTool],
    *,
    tool_choice: dict[str, str] | str | None = None,
    parallel_tool_calls: 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. Supports Anthropic format tool schemas and 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:

  • name of the tool as a string or as dict {"type": "tool", "name": "<<tool_name>>"}: calls corresponding tool;
  • 'auto', {"type: "auto"}, or None: automatically selects a tool (including no tool);
  • 'any' or {"type: "any"}: force at least one tool to be called;

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

parallel_tool_calls

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

Added in version 0.3.2

TYPE: bool | None DEFAULT: None

kwargs

Any additional parameters are passed directly to bind.

TYPE: Any DEFAULT: {}

Example
from langchain_anthropic import ChatAnthropic
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 GetPrice(BaseModel):
    '''Get the price of a specific product.'''

    product: str = Field(..., description="The product to look up.")


model = ChatAnthropic(model="claude-3-5-sonnet-latest", temperature=0)
model_with_tools = model.bind_tools([GetWeather, GetPrice])
model_with_tools.invoke(
    "What is the weather like in San Francisco",
)
# -> AIMessage(
#     content=[
#         {'text': '<thinking>\nBased on the user\'s question, the relevant function to call is GetWeather, which requires the "location" parameter.\n\nThe user has directly specified the location as "San Francisco". Since San Francisco is a well known city, I can reasonably infer they mean San Francisco, CA without needing the state specified.\n\nAll the required parameters are provided, so I can proceed with the API call.\n</thinking>', 'type': 'text'},
#         {'text': None, 'type': 'tool_use', 'id': 'toolu_01SCgExKzQ7eqSkMHfygvYuu', 'name': 'GetWeather', 'input': {'location': 'San Francisco, CA'}}
#     ],
#     response_metadata={'id': 'msg_01GM3zQtoFv8jGQMW7abLnhi', 'model': 'claude-3-5-sonnet-latest', 'stop_reason': 'tool_use', 'stop_sequence': None, 'usage': {'input_tokens': 487, 'output_tokens': 145}},
#     id='run-87b1331e-9251-4a68-acef-f0a018b639cc-0'
# )

Example — force tool call with tool_choice 'any':

```python
from langchain_anthropic import ChatAnthropic
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 GetPrice(BaseModel):
    '''Get the price of a specific product.'''

    product: str = Field(..., description="The product to look up.")


model = ChatAnthropic(model="claude-3-5-sonnet-latest", temperature=0)
model_with_tools = model.bind_tools([GetWeather, GetPrice], tool_choice="any")
model_with_tools.invoke(
    "what is the weather like in San Francisco",
)
```

Example — force specific tool call with tool_choice '<name_of_tool>':

from langchain_anthropic import ChatAnthropic
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 GetPrice(BaseModel):
    '''Get the price of a specific product.'''

    product: str = Field(..., description="The product to look up.")


model = ChatAnthropic(model="claude-3-5-sonnet-latest", temperature=0)
model_with_tools = model.bind_tools([GetWeather, GetPrice], tool_choice="GetWeather")
model_with_tools.invoke("What is the weather like in San Francisco")

Example — cache specific tools:

from langchain_anthropic import ChatAnthropic, convert_to_anthropic_tool
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 GetPrice(BaseModel):
    '''Get the price of a specific product.'''

    product: str = Field(..., description="The product to look up.")


# We'll convert our pydantic class to the anthropic tool format
# before passing to bind_tools so that we can set the 'cache_control'
# field on our tool.
cached_price_tool = convert_to_anthropic_tool(GetPrice)
# Currently the only supported "cache_control" value is
# {"type": "ephemeral"}.
cached_price_tool["cache_control"] = {"type": "ephemeral"}

# We need to pass in extra headers to enable use of the beta cache
# control API.
model = ChatAnthropic(
    model="claude-3-5-sonnet-latest",
    temperature=0,
)
model_with_tools = model.bind_tools([GetWeather, cached_price_tool])
model_with_tools.invoke("What is the weather like in San Francisco")

This outputs:

AIMessage(
    content=[
        {
            "text": "Certainly! I can help you find out the current weather in San Francisco. To get this information, I'll use the GetWeather function. Let me fetch that data for you right away.",
            "type": "text",
        },
        {
            "id": "toolu_01TS5h8LNo7p5imcG7yRiaUM",
            "input": {"location": "San Francisco, CA"},
            "name": "GetWeather",
            "type": "tool_use",
        },
    ],
    response_metadata={
        "id": "msg_01Xg7Wr5inFWgBxE5jH9rpRo",
        "model": "claude-3-5-sonnet-latest",
        "stop_reason": "tool_use",
        "stop_sequence": None,
        "usage": {
            "input_tokens": 171,
            "output_tokens": 96,
            "cache_creation_input_tokens": 1470,
            "cache_read_input_tokens": 0,
        },
    },
    id="run-b36a5b54-5d69-470e-a1b0-b932d00b089e-0",
    tool_calls=[
        {
            "name": "GetWeather",
            "args": {"location": "San Francisco, CA"},
            "id": "toolu_01TS5h8LNo7p5imcG7yRiaUM",
            "type": "tool_call",
        }
    ],
    usage_metadata={
        "input_tokens": 171,
        "output_tokens": 96,
        "total_tokens": 267,
    },
)

If we invoke the tool again, we can see that the "usage" information in the AIMessage.response_metadata shows that we had a cache hit:

AIMessage(
    content=[
        {
            "text": "To get the current weather in San Francisco, I can use the GetWeather function. Let me check that for you.",
            "type": "text",
        },
        {
            "id": "toolu_01HtVtY1qhMFdPprx42qU2eA",
            "input": {"location": "San Francisco, CA"},
            "name": "GetWeather",
            "type": "tool_use",
        },
    ],
    response_metadata={
        "id": "msg_016RfWHrRvW6DAGCdwB6Ac64",
        "model": "claude-3-5-sonnet-latest",
        "stop_reason": "tool_use",
        "stop_sequence": None,
        "usage": {
            "input_tokens": 171,
            "output_tokens": 82,
            "cache_creation_input_tokens": 0,
            "cache_read_input_tokens": 1470,
        },
    },
    id="run-88b1f825-dcb7-4277-ac27-53df55d22001-0",
    tool_calls=[
        {
            "name": "GetWeather",
            "args": {"location": "San Francisco, CA"},
            "id": "toolu_01HtVtY1qhMFdPprx42qU2eA",
            "type": "tool_call",
        }
    ],
    usage_metadata={
        "input_tokens": 171,
        "output_tokens": 82,
        "total_tokens": 253,
    },
)

with_structured_output

with_structured_output(
    schema: dict | type, *, include_raw: bool = False, **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:

  • an Anthropic tool schema,
  • an OpenAI function/tool schema,
  • 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.

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: dict | type

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

kwargs

Additional keyword arguments are ignored.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
Runnable[LanguageModelInput, dict | BaseModel]

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

Example: Pydantic schema (include_raw=False):

from langchain_anthropic import ChatAnthropic
from pydantic import BaseModel


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

    answer: str
    justification: str


model = ChatAnthropic(model="claude-3-5-sonnet-latest", 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: Pydantic schema (include_raw=True):

from langchain_anthropic import ChatAnthropic
from pydantic import BaseModel


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

    answer: str
    justification: str


model = ChatAnthropic(model="claude-3-5-sonnet-latest", 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: dict schema (include_raw=False):

from langchain_anthropic import ChatAnthropic

schema = {
    "name": "AnswerWithJustification",
    "description": "An answer to the user question along with justification for the answer.",
    "input_schema": {
        "type": "object",
        "properties": {
            "answer": {"type": "string"},
            "justification": {"type": "string"},
        },
        "required": ["answer", "justification"],
    },
}
model = ChatAnthropic(model="claude-3-5-sonnet-latest", temperature=0)
structured_model = model.with_structured_output(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.'
# }

get_num_tokens_from_messages

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

Count tokens in a sequence of input messages.

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

kwargs

Additional keyword arguments are passed to the Anthropic messages.count_tokens method.

TYPE: Any DEFAULT: {}

Basic usage:

from langchain_anthropic import ChatAnthropic
from langchain_core.messages import HumanMessage, SystemMessage

model = ChatAnthropic(model="claude-3-5-sonnet-20241022")

messages = [
    SystemMessage(content="You are a scientist"),
    HumanMessage(content="Hello, Claude"),
]
model.get_num_tokens_from_messages(messages)
14

Pass tool schemas:

from langchain_anthropic import ChatAnthropic
from langchain_core.messages import HumanMessage
from langchain_core.tools import tool

model = ChatAnthropic(model="claude-3-5-sonnet-20241022")

@tool(parse_docstring=True)
def get_weather(location: str) -> str:
    """Get the current weather in a given location

    Args:
        location: The city and state, e.g. San Francisco, CA
    """
    return "Sunny"

messages = [
    HumanMessage(content="What's the weather like in San Francisco?"),
]
model.get_num_tokens_from_messages(messages, tools=[get_weather])
403

Behavior changed in 0.3.0

Uses Anthropic's token counting API to count tokens in messages.

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")

__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]

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.

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.