ChatHuggingFace#

class langchain_huggingface.chat_models.huggingface.ChatHuggingFace[source]#

Bases: BaseChatModel

Hugging Face LLM’s as ChatModels.

Works with HuggingFaceTextGenInference, HuggingFaceEndpoint, HuggingFaceHub, and HuggingFacePipeline LLMs.

Upon instantiating this class, the model_id is resolved from the url provided to the LLM, and the appropriate tokenizer is loaded from the HuggingFace Hub.
Setup:
Install langchain-huggingface and ensure your Hugging Face token is saved.
pip install langchain-huggingface
from huggingface_hub import login
login() # You will be prompted for your HF key, which will then be saved locally
Key init args — completion params:

llm: HuggingFaceTextGenInference, HuggingFaceEndpoint, HuggingFaceHub, or
‘HuggingFacePipeline’ LLM to be used.

Key init args — client params:

custom_get_token_ids: Optional[Callable[[str], List[int]]]
Optional encoder to use for counting tokens.

metadata: Optional[Dict[str, Any]]
Metadata to add to the run trace.

tags: Optional[List[str]]
Tags to add to the run trace.

tokenizer: Any verbose: bool

Whether to print out response text.
See full list of supported init args and their descriptions in the params section.
Instantiate:
from langchain_huggingface import HuggingFaceEndpoint,
ChatHuggingFace

llm = HuggingFaceEndpoint(
    repo_id="microsoft/Phi-3-mini-4k-instruct",
    task="text-generation",
    max_new_tokens=512,
    do_sample=False,
    repetition_penalty=1.03,
)

chat = ChatHuggingFace(llm=llm, verbose=True)
Invoke:
messages = [
    ("system", "You are a helpful translator. Translate the user
    sentence to French."),
    ("human", "I love programming."),
]

chat(...).invoke(messages)
AIMessage(content='Je ai une passion pour le programme.

In

French, we use “ai” for masculine subjects and “a” for feminine subjects. Since “programming” is gender-neutral in English, we will go with the masculine “programme”.

Confirmation: “J’aime

le programme.” is more commonly used. The sentence above is technically accurate, but less commonly used in spoken French as “ai” is used less frequently in everyday speech.’, response_metadata={‘token_usage’: ChatCompletionOutputUsage (completion_tokens=100, prompt_tokens=55, total_tokens=155), ‘model’: ‘’, ‘finish_reason’: ‘length’}, id=’run-874c24b7-0272-4c99-b259-5d6d7facbc56-0’)

Stream:

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

content='Je ai une passion pour le programme.

In French, we use

“ai” for masculine subjects and “a” for feminine subjects. Since “programming” is gender-neutral in English, we will go with the masculine “programme”.

Confirmation:

“J’aime le programme.” is more commonly used. The sentence above is technically accurate, but less commonly used in spoken French as “ai” is used less frequently in everyday speech.’ response_metadata={‘token_usage’: ChatCompletionOutputUsage (completion_tokens=100, prompt_tokens=55, total_tokens=155), ‘model’: ‘’, ‘finish_reason’: ‘length’} id=’run-7d7b1967-9612-4f9a-911a-b2b5ca85046a-0’

Async:

await chat.ainvoke(messages)

AIMessage(content='Je déaime le programming.

LittéraleJe

(j’aime) déaime (le) programming.

Note: “Programming” in

French is “programmation”. But here, I used “programming” instead of “programmation” because the user said “I love programming” instead of “I love programming (in French)”, which would be “J’aime la programmation”. By translating the sentence literally, I preserved the original meaning of the user’s sentence.’, id=’run-fd850318-e299-4735-b4c6-3496dc930b1d-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")

chat_with_tools = chat.bind_tools([GetWeather, GetPopulation])
ai_msg = chat_with_tools.invoke("Which city is hotter today and
which is bigger: LA or NY?")
ai_msg.tool_calls

[{'name': 'GetPopulation',
  'args': {'location': 'Los Angeles, CA'},
  'id': '0'}]

Response metadata

ai_msg = chat.invoke(messages)
ai_msg.response_metadata

Note

ChatHuggingFace 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 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 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 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 llm: Any = None#: LLM, must be of type HuggingFaceTextGenInference, HuggingFaceEndpoint, HuggingFaceHub, or HuggingFacePipeline.

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

param model_id: str | None = None#

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

param system_message: SystemMessage = SystemMessage(content='You are a helpful, respectful, and honest assistant.')#

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

param tokenizer: Any = None#

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 OpenAI tool-calling API.

Parameters:

tools (Sequence[Dict[str, Any] | Type | Callable | BaseTool]) – A list of tool definitions to bind to this chat model. Supports any tool definition handled by langchain_core.utils.function_calling.convert_to_openai_tool().
tool_choice (dict | str | Literal['auto', 'none'] | bool | None) – Which tool to require the model to call. Must be the name of the single provided function or “auto” to automatically determine which function to call (if any), or a dict of the form: {“type”: “function”, “function”: {“name”: <<tool_name>>}}.
**kwargs (Any) – Any additional parameters to pass to the Runnable constructor.

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#

Get the number of tokens present in the text.

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

Parameters:: text (str) – The string input to tokenize.
Returns:: The integer number of tokens in the text.
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

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.

Parameters:

schema (Union[Dict, Type]) –
The output schema. Can be passed in as:
- an OpenAI function/tool schema,
- a JSON Schema,
- a TypedDict class (support added in 0.2.26),
- 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.

Changed in version 0.2.26: Added support for TypedDict class.
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 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": Optional[BaseException]

Return type:

Runnable[LanguageModelInput, Union[Dict, BaseModel]]

Example: Pydantic schema (include_raw=False):

from langchain_core.pydantic_v1 import BaseModel

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

llm = ChatModel(model="model-name", 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='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_core.pydantic_v1 import BaseModel

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

llm = ChatModel(model="model-name", 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 (include_raw=False):

from langchain_core.pydantic_v1 import BaseModel
from langchain_core.utils.function_calling import convert_to_openai_tool

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

dict_schema = convert_to_openai_tool(AnswerWithJustification)
llm = ChatModel(model="model-name", 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.'
# }