ChatVertexAI#

class langchain_google_vertexai.chat_models.ChatVertexAI[source]#

Bases: _VertexAICommon, BaseChatModel

Google Cloud Vertex AI chat model integration.

Setup:
You must have the langchain-google-vertexai Python package installed .. code-block:: bash

pip install -U langchain-google-vertexai

And either:

Have credentials configured for your environment (gcloud, workload identity, etc…)

Store the path to a service account JSON file as the GOOGLE_APPLICATION_CREDENTIALS environment variable

This codebase uses the google.auth library which first looks for the application credentials variable mentioned above, and then looks for system-level auth.

For more information, see: https://cloud.google.com/docs/authentication/application-default-credentials#GAC and https://googleapis.dev/python/google-auth/latest/reference/google.auth.html#module-google.auth.

Key init args — completion params:

model: str
Name of ChatVertexAI model to use. e.g. “gemini-1.5-flash-001”, “gemini-1.5-pro-001”, etc.

temperature: Optional[float]
Sampling temperature.

max_tokens: Optional[int]
Max number of tokens to generate.

stop: Optional[List[str]]
Default stop sequences.

safety_settings: Optional[Dict[vertexai.generative_models.HarmCategory, vertexai.generative_models.HarmBlockThreshold]]
The default safety settings to use for all generations.

Key init args — client params:

max_retries: int
Max number of retries.

credentials: Optional[google.auth.credentials.Credentials]
The default custom credentials to use when making API calls. If not provided, credentials will be ascertained from the environment.

project: Optional[str]
The default GCP project to use when making Vertex API calls.

location: str = “us-central1”
The default location to use when making API calls.

request_parallelism: int = 5
The amount of parallelism allowed for requests issued to VertexAI models. Default is 5.

base_url: Optional[str]
Base URL for API requests.

See full list of supported init args and their descriptions in the params section.
Instantiate:
from langchain_google_vertexai import ChatVertexAI

llm = ChatVertexAI(
    model="gemini-1.5-flash-001",
    temperature=0,
    max_tokens=None,
    max_retries=6,
    stop=None,
    # other params...
)
Invoke:
messages = [
    ("system", "You are a helpful translator. Translate the user sentence to French."),
    ("human", "I love programming."),
]
llm.invoke(messages)
AIMessage(content="J'adore programmer.

“, response_metadata={‘is_blocked’: False, ‘safety_ratings’: [{‘category’: ‘HARM_CATEGORY_HATE_SPEECH’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_DANGEROUS_CONTENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_HARASSMENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_SEXUALLY_EXPLICIT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}], ‘citation_metadata’: None, ‘usage_metadata’: {‘prompt_token_count’: 17, ‘candidates_token_count’: 7, ‘total_token_count’: 24}}, id=’run-925ce305-2268-44c4-875f-dde9128520ad-0’)

Stream:

for chunk in llm.stream(messages):
    print(chunk)

AIMessageChunk(content='J', response_metadata={'is_blocked': False, 'safety_ratings': [], 'citation_metadata': None}, id='run-9df01d73-84d9-42db-9d6b-b1466a019e89')
AIMessageChunk(content="'adore programmer.

“, response_metadata={‘is_blocked’: False, ‘safety_ratings’: [{‘category’: ‘HARM_CATEGORY_HATE_SPEECH’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_DANGEROUS_CONTENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_HARASSMENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_SEXUALLY_EXPLICIT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}], ‘citation_metadata’: None}, id=’run-9df01d73-84d9-42db-9d6b-b1466a019e89’)

AIMessageChunk(content=’’, response_metadata={‘is_blocked’: False, ‘safety_ratings’: [], ‘citation_metadata’: None, ‘usage_metadata’: {‘prompt_token_count’: 17, ‘candidates_token_count’: 7, ‘total_token_count’: 24}}, id=’run-9df01d73-84d9-42db-9d6b-b1466a019e89’)

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

AIMessageChunk(content="J'adore programmer.

“, response_metadata={‘is_blocked’: False, ‘safety_ratings’: [{‘category’: ‘HARM_CATEGORY_HATE_SPEECH’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_DANGEROUS_CONTENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_HARASSMENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_SEXUALLY_EXPLICIT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}], ‘citation_metadata’: None, ‘usage_metadata’: {‘prompt_token_count’: 17, ‘candidates_token_count’: 7, ‘total_token_count’: 24}}, id=’run-b7f7492c-4cb5-42d0-8fc3-dce9b293b0fb’)

Async:

await llm.ainvoke(messages)

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

# batch:
# await llm.abatch([messages])

AIMessage(content="J'adore programmer.

“, response_metadata={‘is_blocked’: False, ‘safety_ratings’: [{‘category’: ‘HARM_CATEGORY_HATE_SPEECH’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_DANGEROUS_CONTENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_HARASSMENT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}, {‘category’: ‘HARM_CATEGORY_SEXUALLY_EXPLICIT’, ‘probability_label’: ‘NEGLIGIBLE’, ‘blocked’: False}], ‘citation_metadata’: None, ‘usage_metadata’: {‘prompt_token_count’: 17, ‘candidates_token_count’: 7, ‘total_token_count’: 24}}, id=’run-925ce305-2268-44c4-875f-dde9128520ad-0’)

Tool calling:

from langchain_core.pydantic_v1 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")

llm_with_tools = llm.bind_tools([GetWeather, GetPopulation])
ai_msg = llm_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': '2a2401fa-40db-470d-83ce-4e52de910d9e'},
 {'name': 'GetWeather',
  'args': {'location': 'New York City, NY'},
  'id': '96761deb-ab7f-4ef9-b4b4-6d44562fc46e'},
 {'name': 'GetPopulation',
  'args': {'location': 'Los Angeles, CA'},
  'id': '9147d532-abee-43a2-adb5-12f164300484'},
 {'name': 'GetPopulation',
  'args': {'location': 'New York City, NY'},
  'id': 'c43374ea-bde5-49ca-8487-5b83ebeea1e6'}]

See ChatVertexAI.bind_tools() method for more.

Structured output:

from typing import Optional

from langchain_core.pydantic_v1 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: Optional[int] = Field(description="How funny the joke is, from 1 to 10")

structured_llm = llm.with_structured_output(Joke)
structured_llm.invoke("Tell me a joke about cats")

Joke(setup='What do you call a cat that loves to bowl?', punchline='An alley cat!', rating=None)

See ChatVertexAI.with_structured_output() for more.

Image input:

import base64
import httpx
from langchain_core.messages import HumanMessage

image_url = "https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Gfp-wisconsin-madison-the-nature-boardwalk.jpg/2560px-Gfp-wisconsin-madison-the-nature-boardwalk.jpg"
image_data = base64.b64encode(httpx.get(image_url).content).decode("utf-8")
message = HumanMessage(
    content=[
        {"type": "text", "text": "describe the weather in this image"},
        {
            "type": "image_url",
            "image_url": {"url": f"data:image/jpeg;base64,{image_data}"},
        },
    ],
)
ai_msg = llm.invoke([message])
ai_msg.content

'The weather in this image appears to be sunny and pleasant. The sky is a bright blue with scattered white clouds, suggesting a clear and mild day. The lush green grass indicates recent rainfall or sufficient moisture. The absence of strong shadows suggests that the sun is high in the sky, possibly late afternoon. Overall, the image conveys a sense of tranquility and warmth, characteristic of a beautiful summer day.

‘

You can also point to GCS files which is faster / more efficient because bytes are transferred back and forth.

llm.invoke(
    [
        HumanMessage(
            [
                "What's in the image?",
                {
                    "type": "media",
                    "file_uri": "gs://cloud-samples-data/generative-ai/image/scones.jpg",
                    "mime_type": "image/jpeg",
                },
            ]
        )
    ]
).content

'The image is of five blueberry scones arranged on a piece of baking paper.

Here is a list of what is in the picture: * Five blueberry scones: They are scattered across the parchment paper, dusted with powdered sugar. * Two cups of coffee: Two white cups with saucers. One appears full, the other partially drunk. * A bowl of blueberries: A brown bowl is filled with fresh blueberries, placed near the scones. * A spoon: A silver spoon with the words “Let’s Jam” rests on the paper. * Pink peonies: Several pink peonies lie beside the scones, adding a touch of color. * Baking paper: The scones, cups, bowl, and spoon are arranged on a piece of white baking paper, splattered with purple. The paper is crinkled and sits on a dark surface.

The image has a rustic and delicious feel, suggesting a cozy and enjoyable breakfast or brunch setting. ‘

Video input:

NOTE: Currently only supported for gemini-...-vision models.

llm = ChatVertexAI(model="gemini-1.0-pro-vision")

llm.invoke(
    [
        HumanMessage(
            [
                "What's in the video?",
                {
                    "type": "media",
                    "file_uri": "gs://cloud-samples-data/video/animals.mp4",
                    "mime_type": "video/mp4",
                },
            ]
        )
    ]
).content

'The video is about a new feature in Google Photos called "Zoomable Selfies". The feature allows users to take selfies with animals at the zoo. The video shows several examples of people taking selfies with animals, including a tiger, an elephant, and a sea otter. The video also shows how the feature works. Users simply need to open the Google Photos app and select the "Zoomable Selfies" option. Then, they need to choose an animal from the list of available animals. The app will then guide the user through the process of taking the selfie.'

Audio input:

from langchain_core.messages import HumanMessage

llm = ChatVertexAI(model="gemini-1.5-flash-001")

llm.invoke(
    [
        HumanMessage(
            [
                "What's this audio about?",
                {
                    "type": "media",
                    "file_uri": "gs://cloud-samples-data/generative-ai/audio/pixel.mp3",
                    "mime_type": "audio/mpeg",
                },
            ]
        )
    ]
).content

"This audio is an interview with two product managers from Google who work on Pixel feature drops. They discuss how feature drops are important for showcasing how Google devices are constantly improving and getting better. They also discuss some of the highlights of the January feature drop and the new features coming in the March drop for Pixel phones and Pixel watches. The interview concludes with discussion of how user feedback is extremely important to them in deciding which features to include in the feature drops. "

Token usage:

ai_msg = llm.invoke(messages)
ai_msg.usage_metadata

{'input_tokens': 17, 'output_tokens': 7, 'total_tokens': 24}

Response metadata

ai_msg = llm.invoke(messages)
ai_msg.response_metadata

{'is_blocked': False,
 'safety_ratings': [{'category': 'HARM_CATEGORY_HATE_SPEECH',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False},
  {'category': 'HARM_CATEGORY_DANGEROUS_CONTENT',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False},
  {'category': 'HARM_CATEGORY_HARASSMENT',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False},
  {'category': 'HARM_CATEGORY_SEXUALLY_EXPLICIT',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False}],
 'usage_metadata': {'prompt_token_count': 17,
  'candidates_token_count': 7,
  'total_token_count': 24}}

Safety settings

from langchain_google_vertexai import HarmBlockThreshold, HarmCategory

llm = ChatVertexAI(
    model="gemini-1.5-pro",
    safety_settings={
        HarmCategory.HARM_CATEGORY_HATE_SPEECH: HarmBlockThreshold.BLOCK_LOW_AND_ABOVE,
        HarmCategory.HARM_CATEGORY_DANGEROUS_CONTENT: HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE,
        HarmCategory.HARM_CATEGORY_HARASSMENT: HarmBlockThreshold.BLOCK_LOW_AND_ABOVE,
        HarmCategory.HARM_CATEGORY_SEXUALLY_EXPLICIT: HarmBlockThreshold.BLOCK_ONLY_HIGH,
    },
)

llm.invoke(messages).response_metadata

{'is_blocked': False,
 'safety_ratings': [{'category': 'HARM_CATEGORY_HATE_SPEECH',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False},
  {'category': 'HARM_CATEGORY_DANGEROUS_CONTENT',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False},
  {'category': 'HARM_CATEGORY_HARASSMENT',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False},
  {'category': 'HARM_CATEGORY_SEXUALLY_EXPLICIT',
   'probability_label': 'NEGLIGIBLE',
   'blocked': False}],
 'usage_metadata': {'prompt_token_count': 17,
  'candidates_token_count': 7,
  'total_token_count': 24}}

Needed for mypy typing to recognize model_name as a valid arg.

Note

ChatVertexAI implements the standard Runnable Interface. 🏃

The Runnable Interface has additional methods that are available on runnables, such as with_types, with_retry, assign, bind, get_graph, and more.

param additional_headers: Dict[str, str] | None = None#: A key-value dictionary representing additional headers for the model call

param api_endpoint: str | None = None (alias 'base_url')#: Desired API endpoint, e.g., us-central1-aiplatform.googleapis.com

param api_transport: str | None = None#: The desired API transport method, can be either ‘grpc’ or ‘rest’. Uses the default parameter in vertexai.init if defined.

param cache: BaseCache | bool | None = None#

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.

param cached_content: str | None = None#: Optional. Use the model in cache mode. Only supported in Gemini 1.5 and later models. Must be a string containing the cache name (A sequence of numbers)

param callback_manager: BaseCallbackManager | None = None#: Deprecated since version 0.1.7: Use callbacks instead.

Callback manager to add to the run trace.

param callbacks: Callbacks = None#: Callbacks to add to the run trace.

param client_cert_source: Callable[[], Tuple[bytes, bytes]] | None = None#: A callback which returns client certificate bytes and private key bytes both

param convert_system_message_to_human: bool = False#: [Deprecated] Since new Gemini models support setting a System Message, setting this parameter to True is discouraged.

param credentials: Any = None#: The default custom credentials (google.auth.credentials.Credentials) to use

param custom_get_token_ids: Callable[[str], List[int]] | None = None#: Optional encoder to use for counting tokens.

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

Whether to disable streaming for this model.

If streaming is bypassed, then stream()/astream() 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.
If False (default), will always use streaming case if available.

param examples: List[BaseMessage] | None = None#

param full_model_name: str | None = None#: The full name of the model’s endpoint.

param location: str = 'us-central1'#: The default location to use when making API calls.

param max_output_tokens: int | None = None (alias 'max_tokens')#: Token limit determines the maximum amount of text output from one prompt.

param max_retries: int = 6#: The maximum number of retries to make when generating.

param metadata: Dict[str, Any] | None = None#: Metadata to add to the run trace.

param model_name: str = 'chat-bison-default' (alias 'model')#: Underlying model name.

param n: int = 1#: How many completions to generate for each prompt.

param project: str | None = None#: The default GCP project to use when making Vertex API calls.

param rate_limiter: BaseRateLimiter | None = None#: An optional rate limiter to use for limiting the number of requests.

param request_parallelism: int = 5#: The amount of parallelism allowed for requests issued to VertexAI models.

param response_mime_type: str | None = None#

Optional. Output response mimetype of the generated candidate text. Only

supported in Gemini 1.5 and later models. Supported mimetype:

“text/plain”: (default) Text output.
“application/json”: JSON response in the candidates.

The model also needs to be prompted to output the appropriate response type, otherwise the behavior is undefined. This is a preview feature.

param response_schema: Dict[str, Any] | None = None#: Optional. Enforce an schema to the output. Only works when response_mime_type is set to application/json. The format of the dictionary should follow Open API schema.

param safety_settings: 'SafetySettingsType' | None = None#

The default safety settings to use for all generations.

For example:

from langchain_google_vertexai import HarmBlockThreshold, HarmCategory

safety_settings = {
HarmCategory.HARM_CATEGORY_UNSPECIFIED: HarmBlockThreshold.BLOCK_NONE, HarmCategory.HARM_CATEGORY_DANGEROUS_CONTENT: HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE, HarmCategory.HARM_CATEGORY_HATE_SPEECH: HarmBlockThreshold.BLOCK_ONLY_HIGH, HarmCategory.HARM_CATEGORY_HARASSMENT: HarmBlockThreshold.BLOCK_LOW_AND_ABOVE, HarmCategory.HARM_CATEGORY_SEXUALLY_EXPLICIT: HarmBlockThreshold.BLOCK_NONE,

}

param stop: List[str] | None = None (alias 'stop_sequences')#: Optional list of stop words to use when generating.

param streaming: bool = False#: Whether to stream the results or not.

param tags: List[str] | None = None#: Tags to add to the run trace.

param temperature: float | None = None#: Sampling temperature, it controls the degree of randomness in token selection.

param top_k: int | None = None#: How the model selects tokens for output, the next token is selected from

param top_p: float | None = None#: Tokens are selected from most probable to least until the sum of their

param tuned_model_name: str | None = None#: The name of a tuned model. If tuned_model_name is passed model_name will be used to determine the model family

param verbose: bool [Optional]#: Whether to print out response text.

__call__(messages: List[BaseMessage], stop: List[str] | None = None, callbacks: List[BaseCallbackHandler] | BaseCallbackManager | None = None, **kwargs: Any) → BaseMessage#

Deprecated since version langchain-core==0.1.7: Use invoke instead.

Parameters:

messages (List[BaseMessage]) –
stop (List[str] | None) –
callbacks (List[BaseCallbackHandler] | BaseCallbackManager | None) –
kwargs (Any) –

Return type:

BaseMessage

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

Parameters:

inputs (List[Input]) – A list of inputs to the Runnable.
config (RunnableConfig | List[RunnableConfig] | None) – 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. Defaults to None.
return_exceptions (bool) – Whether to return exceptions instead of raising them. Defaults to False.
kwargs (Any | None) – Additional keyword arguments to pass to the Runnable.

Returns:

A list of outputs from the Runnable.

Return type:

List[Output]

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, yielding results as they complete.

Parameters:

inputs (Sequence[Input]) – A list of inputs to the Runnable.
config (RunnableConfig | Sequence[RunnableConfig] | None) – 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. Defaults to None. Defaults to None.
return_exceptions (bool) – Whether to return exceptions instead of raising them. Defaults to False.
kwargs (Any | None) – Additional keyword arguments to pass to the Runnable.

Yields:

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

Return type:

AsyncIterator[Tuple[int, Output | Exception]]

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:

take advantage of batched calls,
need more output from the model than just the top generated value,
are building chains that are agnostic to the underlying language model
type (e.g., pure text completion models vs chat models).

Parameters:

messages (List[List[BaseMessage]]) – List of list of messages.
stop (List[str] | None) – Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.
callbacks (List[BaseCallbackHandler] | BaseCallbackManager | None) – Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.
**kwargs (Any) – Arbitrary additional keyword arguments. These are usually passed to the model provider API call.
tags (List[str] | None) –
metadata (Dict[str, Any] | None) –
run_name (str | None) –
run_id (UUID | None) –
**kwargs –

Returns:

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

Return type:

LLMResult

async agenerate_prompt(prompts: List[PromptValue], stop: List[str] | None = None, callbacks: List[BaseCallbackHandler] | BaseCallbackManager | None = 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:

take advantage of batched calls,
need more output from the model than just the top generated value,
are building chains that are agnostic to the underlying language model
type (e.g., pure text completion models vs chat models).

Parameters:

prompts (List[PromptValue]) – List of PromptValues. A PromptValue is an object that can be converted to match the format of any language model (string for pure text generation models and BaseMessages for chat models).
stop (List[str] | None) – Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.
callbacks (List[BaseCallbackHandler] | BaseCallbackManager | None) – Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.
**kwargs (Any) – Arbitrary additional keyword arguments. These are usually passed to the model provider API call.

Returns:

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

Return type:

LLMResult

async ainvoke(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: List[str] | None = None, **kwargs: Any) → BaseMessage#

Default implementation of ainvoke, calls invoke from a thread.

The default implementation allows usage of async code even if the Runnable did not implement a native async version of invoke.

Subclasses should override this method if they can run asynchronously.

Parameters:

input (LanguageModelInput) –
config (Optional[RunnableConfig]) –
stop (Optional[List[str]]) –
kwargs (Any) –

Return type:

BaseMessage

async apredict(text: str, *, stop: Sequence[str] | None = None, **kwargs: Any) → str#

Deprecated since version langchain-core==0.1.7: Use ainvoke instead.

Parameters:

text (str) –
stop (Sequence[str] | None) –
kwargs (Any) –

Return type:

str

async apredict_messages(messages: List[BaseMessage], *, stop: Sequence[str] | None = None, **kwargs: Any) → BaseMessage#

Deprecated since version langchain-core==0.1.7: Use ainvoke instead.

Parameters:

messages (List[BaseMessage]) –
stop (Sequence[str] | None) –
kwargs (Any) –

Return type:

BaseMessage

async astream(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: List[str] | None = None, **kwargs: Any) → AsyncIterator[BaseMessageChunk]#

Default implementation of astream, which calls ainvoke. Subclasses should override this method if they support streaming output.

Parameters:

input (LanguageModelInput) – The input to the Runnable.
config (Optional[RunnableConfig]) – The config to use for the Runnable. Defaults to None.
kwargs (Any) – Additional keyword arguments to pass to the Runnable.
stop (Optional[List[str]]) –

Yields:

The output of the Runnable.

Return type:

AsyncIterator[BaseMessageChunk]

astream_events(input: Any, config: RunnableConfig | None = None, *, version: Literal['v1', '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[StandardStreamEvent | CustomStreamEvent]#

Beta

This API is in beta and may change in the future.

Generate a stream of events.

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

A StreamEvent is a dictionary with the following schema:

event: str - Event names are of the
format: on_[runnable_type]_(start|stream|end).
name: str - The name of the Runnable that generated the event.
run_id: str - 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: List[str] - 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: Optional[List[str]] - The tags of the Runnable that generated
the event.
metadata: Optional[Dict[str, Any]] - The metadata of the Runnable
that generated the event.
data: Dict[str, Any]

Below is a table that illustrates some evens 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.

ATTENTION 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"]})

Example:

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)

Parameters:

input (Any) – The input to the Runnable.
config (RunnableConfig | None) – The config to use for the Runnable.
version (Literal['v1', 'v2']) – 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.
include_names (Sequence[str] | None) – Only include events from runnables with matching names.
include_types (Sequence[str] | None) – Only include events from runnables with matching types.
include_tags (Sequence[str] | None) – Only include events from runnables with matching tags.
exclude_names (Sequence[str] | None) – Exclude events from runnables with matching names.
exclude_types (Sequence[str] | None) – Exclude events from runnables with matching types.
exclude_tags (Sequence[str] | None) – Exclude events from runnables with matching tags.
kwargs (Any) – 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.

Yields:

An async stream of StreamEvents.

Raises:

NotImplementedError – If the version is not v1 or v2.

Return type:

AsyncIterator[StandardStreamEvent | CustomStreamEvent]

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

Parameters:

inputs (List[Input]) –
config (RunnableConfig | List[RunnableConfig] | None) –
return_exceptions (bool) –
kwargs (Any | None) –

Return type:

List[Output]

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, yielding results as they complete.

Parameters:

inputs (Sequence[Input]) –
config (RunnableConfig | Sequence[RunnableConfig] | None) –
return_exceptions (bool) –
kwargs (Any | None) –

Return type:

Iterator[Tuple[int, Output | Exception]]

Bind tool-like objects to this chat model.

Assumes model is compatible with Vertex tool-calling API.

Parameters:

tools (Sequence[Tool | Tool | _ToolDictLike | BaseTool | Type[BaseModel] | FunctionDescription | Callable | FunctionDeclaration | Dict[str, Any]]) – A list of tool definitions to bind to this chat model. Can be a pydantic model, callable, or BaseTool. Pydantic models, callables, and BaseTools will be automatically converted to their schema dictionary representation.
**kwargs (Any) – Any additional parameters to pass to the Runnable constructor.
tool_config (_ToolConfigDict | None) –
tool_choice (dict | List[str] | str | Literal['auto', 'none', 'any'] | ~typing.Literal[True] | bool | None) –
**kwargs –

Return type:

call_as_llm(message: str, stop: List[str] | None = None, **kwargs: Any) → str#

Deprecated since version langchain-core==0.1.7: Use invoke instead.

Parameters:

message (str) –
stop (List[str] | None) –
kwargs (Any) –

Return type:

str

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 Runnables that can be set at runtime.

Parameters:

which (ConfigurableField) – The ConfigurableField instance that will be used to select the alternative.
default_key (str) – The default key to use if no alternative is selected. Defaults to “default”.
prefix_keys (bool) – Whether to prefix the keys with the ConfigurableField id. Defaults to False.
**kwargs (Runnable[Input, Output] | Callable[[], Runnable[Input, Output]]) – A dictionary of keys to Runnable instances or callables that return Runnable instances.

Returns:

A new Runnable with the alternatives configured.

Return type:

RunnableSerializable[Input, Output]

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

model = ChatAnthropic(
    model_name="claude-3-sonnet-20240229"
).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
)

configurable_fields(**kwargs: ConfigurableField | ConfigurableFieldSingleOption | ConfigurableFieldMultiOption) → RunnableSerializable[Input, Output]#

Configure particular Runnable fields at runtime.

Parameters:: **kwargs (ConfigurableField | ConfigurableFieldSingleOption | ConfigurableFieldMultiOption) – A dictionary of ConfigurableField instances to configure.
Returns:: A new Runnable with the fields configured.
Return type:: RunnableSerializable[Input, Output]

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
)

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:

take advantage of batched calls,
need more output from the model than just the top generated value,
are building chains that are agnostic to the underlying language model
type (e.g., pure text completion models vs chat models).

Parameters:

messages (List[List[BaseMessage]]) – List of list of messages.
stop (List[str] | None) – Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.
callbacks (List[BaseCallbackHandler] | BaseCallbackManager | None) – Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.
**kwargs (Any) – Arbitrary additional keyword arguments. These are usually passed to the model provider API call.
tags (List[str] | None) –
metadata (Dict[str, Any] | None) –
run_name (str | None) –
run_id (UUID | None) –
**kwargs –

Returns:

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

Return type:

LLMResult

generate_prompt(prompts: List[PromptValue], stop: List[str] | None = None, callbacks: List[BaseCallbackHandler] | BaseCallbackManager | 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:

take advantage of batched calls,
need more output from the model than just the top generated value,
are building chains that are agnostic to the underlying language model
type (e.g., pure text completion models vs chat models).

Parameters:

prompts (List[PromptValue]) – List of PromptValues. A PromptValue is an object that can be converted to match the format of any language model (string for pure text generation models and BaseMessages for chat models).
stop (List[str] | None) – Stop words to use when generating. Model output is cut off at the first occurrence of any of these substrings.
callbacks (List[BaseCallbackHandler] | BaseCallbackManager | None) – Callbacks to pass through. Used for executing additional functionality, such as logging or streaming, throughout generation.
**kwargs (Any) – Arbitrary additional keyword arguments. These are usually passed to the model provider API call.

Returns:

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

Return type:

LLMResult

get_num_tokens(text: str) → int[source]#

Get the number of tokens present in the text.

Parameters:: text (str) –
Return type:: int

get_num_tokens_from_messages(messages: List[BaseMessage]) → int#

Get the number of tokens in the messages.

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

Parameters:: messages (List[BaseMessage]) – The message inputs to tokenize.
Returns:: The sum of the number of tokens across the messages.
Return type:: int

get_token_ids(text: str) → List[int]#

Return the ordered ids of the tokens in a text.

Parameters:

text (str) – The string input to tokenize.

Returns:

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

Return type:

List[int]

invoke(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: List[str] | None = None, **kwargs: Any) → BaseMessage#

Transform a single input into an output. Override to implement.

Parameters:

input (LanguageModelInput) – The input to the Runnable.
config (Optional[RunnableConfig]) – 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.
stop (Optional[List[str]]) –
kwargs (Any) –

Returns:

The output of the Runnable.

Return type:

BaseMessage

predict(text: str, *, stop: Sequence[str] | None = None, **kwargs: Any) → str#

Deprecated since version langchain-core==0.1.7: Use invoke instead.

Parameters:

text (str) –
stop (Sequence[str] | None) –
kwargs (Any) –

Return type:

str

predict_messages(messages: List[BaseMessage], *, stop: Sequence[str] | None = None, **kwargs: Any) → BaseMessage#

Deprecated since version langchain-core==0.1.7: Use invoke instead.

Parameters:

messages (List[BaseMessage]) –
stop (Sequence[str] | None) –
kwargs (Any) –

Return type:

BaseMessage

stream(input: LanguageModelInput, config: RunnableConfig | None = None, *, stop: List[str] | None = None, **kwargs: Any) → Iterator[BaseMessageChunk]#

Default implementation of stream, which calls invoke. Subclasses should override this method if they support streaming output.

Parameters:

input (LanguageModelInput) – The input to the Runnable.
config (Optional[RunnableConfig]) – The config to use for the Runnable. Defaults to None.
kwargs (Any) – Additional keyword arguments to pass to the Runnable.
stop (Optional[List[str]]) –

Yields:

The output of the Runnable.

Return type:

Iterator[BaseMessageChunk]

to_json() → SerializedConstructor | SerializedNotImplemented#

Serialize the Runnable to JSON.

Returns:: A JSON-serializable representation of the Runnable.
Return type:: SerializedConstructor | SerializedNotImplemented

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

Changed in version 1.1.0: Return type corrected in version 1.1.0. Previously if a dict schema was provided then the output had the form [{"args": {}, "name": "schema_name"}] where the output was a list with a single dict and the “args” of the one dict corresponded to the schema. As of 1.1.0 this has been fixed so that the schema (the value corresponding to the old “args” key) is returned directly.

Parameters:

schema (Dict | Type[BaseModel]) – The output schema as a dict or a Pydantic class. If a Pydantic class then the model output will be an object of that class. If a dict then the model output will be a dict. With a Pydantic class the returned attributes will be validated, whereas with a dict they will not be. If method is “function_calling” and schema is a dict, then the dict must match the OpenAI function-calling spec.
include_raw (bool) – 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”.
kwargs (Any) –

Returns:

A Runnable that takes any ChatModel input. If include_raw is True then a dict with keys — raw: BaseMessage, parsed: Optional[_DictOrPydantic], parsing_error: Optional[BaseException]. If include_raw is False then just _DictOrPydantic is returned, where _DictOrPydantic depends on the schema. If schema is a Pydantic class then _DictOrPydantic is the Pydantic class. If schema is a dict then _DictOrPydantic is a dict.

Return type:

Example: Pydantic schema, exclude raw:

from langchain_core.pydantic_v1 import BaseModel
from langchain_google_vertexai import ChatVertexAI

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

llm = ChatVertexAI(model_name="gemini-pro", temperature=0)
structured_llm = llm.with_structured_output(AnswerWithJustification)

structured_llm.invoke("What weighs more a pound of bricks or a pound of feathers")
# -> AnswerWithJustification(
#     answer='They weigh the same.', justification='A pound is a pound.'
# )

Example: Pydantic schema, include raw:

from langchain_core.pydantic_v1 import BaseModel
from langchain_google_vertexai import ChatVertexAI

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

llm = ChatVertexAI(model_name="gemini-pro", temperature=0)
structured_llm = llm.with_structured_output(AnswerWithJustification, include_raw=True)

structured_llm.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, exclude raw:

from langchain_core.pydantic_v1 import BaseModel
from langchain_core.utils.function_calling import convert_to_openai_function
from langchain_google_vertexai import ChatVertexAI

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

dict_schema = convert_to_openai_function(AnswerWithJustification)
llm = ChatVertexAI(model_name="gemini-pro", temperature=0)
structured_llm = llm.with_structured_output(dict_schema)

structured_llm.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.'
# }

property async_prediction_client: PredictionServiceAsyncClient#: Returns PredictionServiceClient.

property prediction_client: PredictionServiceClient#: Returns PredictionServiceClient.

task_executor: ClassVar[Executor | None] = FieldInfo(exclude=True, extra={})#

Examples using ChatVertexAI