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LangSmith utilities

langchain-classic documentation

These docs cover the langchain-classic package. This package will be maintained for security vulnerabilities until December 2026. Users are encouraged to migrate to the langchain package for the latest features and improvements. See docs for langchain

langchain_classic.smith

LangSmith utilities.

This module provides utilities for connecting to LangSmith.

Evaluation

LangSmith helps you evaluate Chains and other language model application components using a number of LangChain evaluators. An example of this is shown below, assuming you've created a LangSmith dataset called <my_dataset_name>:

from langsmith import Client
from langchain_openai import ChatOpenAI
from langchain_classic.chains import LLMChain
from langchain_classic.smith import RunEvalConfig, run_on_dataset


# Chains may have memory. Passing in a constructor function lets the
# evaluation framework avoid cross-contamination between runs.
def construct_chain():
    model = ChatOpenAI(temperature=0)
    chain = LLMChain.from_string(model, "What's the answer to {your_input_key}")
    return chain


# Load off-the-shelf evaluators via config or the EvaluatorType (string or enum)
evaluation_config = RunEvalConfig(
    evaluators=[
        "qa",  # "Correctness" against a reference answer
        "embedding_distance",
        RunEvalConfig.Criteria("helpfulness"),
        RunEvalConfig.Criteria(
            {
                "fifth-grader-score": "Do you have to be smarter than a fifth "
                "grader to answer this question?"
            }
        ),
    ]
)

client = Client()
run_on_dataset(
    client,
    "<my_dataset_name>",
    construct_chain,
    evaluation=evaluation_config,
)

You can also create custom evaluators by subclassing the StringEvaluator <langchain.evaluation.schema.StringEvaluator> or LangSmith's RunEvaluator classes.

from typing import Optional
from langchain_classic.evaluation import StringEvaluator


class MyStringEvaluator(StringEvaluator):
    @property
    def requires_input(self) -> bool:
        return False

    @property
    def requires_reference(self) -> bool:
        return True

    @property
    def evaluation_name(self) -> str:
        return "exact_match"

    def _evaluate_strings(
        self, prediction, reference=None, input=None, **kwargs
    ) -> dict:
        return {"score": prediction == reference}


evaluation_config = RunEvalConfig(
    custom_evaluators=[MyStringEvaluator()],
)

run_on_dataset(
    client,
    "<my_dataset_name>",
    construct_chain,
    evaluation=evaluation_config,
)

Primary Functions

  • arun_on_dataset <langchain.smith.evaluation.runner_utils.arun_on_dataset>: Asynchronous function to evaluate a chain, agent, or other LangChain component over a dataset.
  • run_on_dataset <langchain.smith.evaluation.runner_utils.run_on_dataset>: Function to evaluate a chain, agent, or other LangChain component over a dataset.
  • RunEvalConfig <langchain.smith.evaluation.config.RunEvalConfig>: Class representing the configuration for running evaluation. You can select evaluators by EvaluatorType <langchain.evaluation.schema.EvaluatorType> or config, or you can pass in custom_evaluators.
FUNCTION DESCRIPTION
arun_on_dataset

Run on dataset.

run_on_dataset

Run on dataset.

RunEvalConfig

Bases: BaseModel

Configuration for a run evaluation.

evaluators class-attribute instance-attribute

evaluators: list[SINGLE_EVAL_CONFIG_TYPE | CUSTOM_EVALUATOR_TYPE] = Field(
    default_factory=list
)

Configurations for which evaluators to apply to the dataset run. Each can be the string of an EvaluatorType <langchain.evaluation.schema.EvaluatorType>, such as EvaluatorType.QA, the evaluator type string ("qa"), or a configuration for a given evaluator (e.g., RunEvalConfig.QA <langchain.smith.evaluation.config.RunEvalConfig.QA>).

custom_evaluators class-attribute instance-attribute

custom_evaluators: list[CUSTOM_EVALUATOR_TYPE] | None = None

Custom evaluators to apply to the dataset run.

batch_evaluators class-attribute instance-attribute

batch_evaluators: list[BATCH_EVALUATOR_LIKE] | None = None

Evaluators that run on an aggregate/batch level.

These generate one or more metrics that are assigned to the full test run. As a result, they are not associated with individual traces.

reference_key class-attribute instance-attribute

reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute

prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute

input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

eval_llm class-attribute instance-attribute

eval_llm: BaseLanguageModel | None = None

The language model to pass to any evaluators that require one.

Criteria

Bases: SingleKeyEvalConfig

Configuration for a reference-free criteria evaluator.

ATTRIBUTE DESCRIPTION
criteria

The criteria to evaluate.

TYPE: CRITERIA_TYPE | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

LabeledCriteria

Bases: SingleKeyEvalConfig

Configuration for a labeled (with references) criteria evaluator.

ATTRIBUTE DESCRIPTION
criteria

The criteria to evaluate.

TYPE: CRITERIA_TYPE | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

EmbeddingDistance

Bases: SingleKeyEvalConfig

Configuration for an embedding distance evaluator.

ATTRIBUTE DESCRIPTION
embeddings

The embeddings to use for computing the distance.

TYPE: Embeddings | None

distance_metric

The distance metric to use for computing the distance.

TYPE: EmbeddingDistance | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

StringDistance

Bases: SingleKeyEvalConfig

Configuration for a string distance evaluator.

ATTRIBUTE DESCRIPTION
distance

The string distance metric to use (damerau_levenshtein, levenshtein, jaro, or jaro_winkler).

TYPE: StringDistance | None

normalize_score

Whether to normalize the distance to between 0 and 1. Applies only to the Levenshtein and Damerau-Levenshtein distances.

TYPE: bool

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

QA

Bases: SingleKeyEvalConfig

Configuration for a QA evaluator.

ATTRIBUTE DESCRIPTION
prompt

The prompt template to use for generating the question.

TYPE: BasePromptTemplate | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

ContextQA

Bases: SingleKeyEvalConfig

Configuration for a context-based QA evaluator.

ATTRIBUTE DESCRIPTION
prompt

The prompt template to use for generating the question.

TYPE: BasePromptTemplate | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

CoTQA

Bases: SingleKeyEvalConfig

Configuration for a context-based QA evaluator.

ATTRIBUTE DESCRIPTION
prompt

The prompt template to use for generating the question.

TYPE: BasePromptTemplate | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

JsonValidity

Bases: SingleKeyEvalConfig

Configuration for a json validity evaluator.

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

JsonEqualityEvaluator

Bases: EvalConfig

Configuration for a json equality evaluator.

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

ExactMatch

Bases: SingleKeyEvalConfig

Configuration for an exact match string evaluator.

ATTRIBUTE DESCRIPTION
ignore_case

Whether to ignore case when comparing strings.

TYPE: bool

ignore_punctuation

Whether to ignore punctuation when comparing strings.

TYPE: bool

ignore_numbers

Whether to ignore numbers when comparing strings.

TYPE: bool

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

RegexMatch

Bases: SingleKeyEvalConfig

Configuration for a regex match string evaluator.

ATTRIBUTE DESCRIPTION
flags

The flags to pass to the regex. Example: re.IGNORECASE.

TYPE: int

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

ScoreString

Bases: SingleKeyEvalConfig

Configuration for a score string evaluator.

This is like the criteria evaluator but it is configured by default to return a score on the scale from 1-10.

It is recommended to normalize these scores by setting normalize_by to 10.

ATTRIBUTE DESCRIPTION
criteria

The criteria to evaluate.

TYPE: CRITERIA_TYPE | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

normalize_by

If you want to normalize the score, the denominator to use. If not provided, the score will be between 1 and 10.

TYPE: float | None

prompt

The prompt template to use for evaluation.

TYPE: BasePromptTemplate | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

LabeledScoreString

Bases: ScoreString

Configuration for a labeled score string evaluator.

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

arun_on_dataset async

arun_on_dataset(
    client: Client | None,
    dataset_name: str,
    llm_or_chain_factory: MODEL_OR_CHAIN_FACTORY,
    *,
    evaluation: RunEvalConfig | None = None,
    dataset_version: datetime | str | None = None,
    concurrency_level: int = 5,
    project_name: str | None = None,
    project_metadata: dict[str, Any] | None = None,
    verbose: bool = False,
    revision_id: str | None = None,
    **kwargs: Any,
) -> dict[str, Any]

Run on dataset.

Run the Chain or language model on a dataset and store traces to the specified project name.

For the (usually faster) async version of this function, see arun_on_dataset.

PARAMETER DESCRIPTION
dataset_name

Name of the dataset to run the chain on.

TYPE: str

llm_or_chain_factory

Language model or Chain constructor to run over the dataset. The Chain constructor is used to permit independent calls on each example without carrying over state.

TYPE: MODEL_OR_CHAIN_FACTORY

evaluation

Configuration for evaluators to run on the results of the chain.

TYPE: RunEvalConfig | None DEFAULT: None

dataset_version

Optional version of the dataset.

TYPE: datetime | str | None DEFAULT: None

concurrency_level

The number of async tasks to run concurrently.

TYPE: int DEFAULT: 5

project_name

Name of the project to store the traces in. Defaults to {dataset_name}-{chain class name}-{datetime}.

TYPE: str | None DEFAULT: None

project_metadata

Optional metadata to add to the project. Useful for storing information the test variant. (prompt version, model version, etc.)

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

client

LangSmith client to use to access the dataset and to log feedback and run traces.

TYPE: Client | None

verbose

Whether to print progress.

TYPE: bool DEFAULT: False

revision_id

Optional revision identifier to assign this test run to track the performance of different versions of your system.

TYPE: str | None DEFAULT: None

**kwargs

Should not be used, but is provided for backwards compatibility.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
dict[str, Any]

dict containing the run's project name and the resulting model outputs.

Examples:

from langsmith import Client
from langchain_openai import ChatOpenAI
from langchain_classic.chains import LLMChain
from langchain_classic.smith import smith_eval.RunEvalConfig, run_on_dataset

# Chains may have memory. Passing in a constructor function lets the
# evaluation framework avoid cross-contamination between runs.
def construct_chain():
    model = ChatOpenAI(temperature=0)
    chain = LLMChain.from_string(
        model,
        "What's the answer to {your_input_key}"
    )
    return chain

# Load off-the-shelf evaluators via config or the EvaluatorType (string or enum)
evaluation_config = smith_eval.RunEvalConfig(
    evaluators=[
        "qa",  # "Correctness" against a reference answer
        "embedding_distance",
        smith_eval.RunEvalConfig.Criteria("helpfulness"),
        smith_eval.RunEvalConfig.Criteria({
            "fifth-grader-score": "Do you have to be smarter than a fifth "
            "grader to answer this question?"
        }),
    ]
)

client = Client()
await arun_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)
You can also create custom evaluators by subclassing the StringEvaluator or LangSmith'sRunEvaluator` classes.

from typing import Optional
from langchain_classic.evaluation import StringEvaluator


class MyStringEvaluator(StringEvaluator):
    @property
    def requires_input(self) -> bool:
        return False

    @property
    def requires_reference(self) -> bool:
        return True

    @property
    def evaluation_name(self) -> str:
        return "exact_match"

    def _evaluate_strings(
        self, prediction, reference=None, input=None, **kwargs
    ) -> dict:
        return {"score": prediction == reference}


evaluation_config = smith_eval.RunEvalConfig(
    custom_evaluators=[MyStringEvaluator()],
)

await arun_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)

run_on_dataset

run_on_dataset(
    client: Client | None,
    dataset_name: str,
    llm_or_chain_factory: MODEL_OR_CHAIN_FACTORY,
    *,
    evaluation: RunEvalConfig | None = None,
    dataset_version: datetime | str | None = None,
    concurrency_level: int = 5,
    project_name: str | None = None,
    project_metadata: dict[str, Any] | None = None,
    verbose: bool = False,
    revision_id: str | None = None,
    **kwargs: Any,
) -> dict[str, Any]

Run on dataset.

Run the Chain or language model on a dataset and store traces to the specified project name.

For the (usually faster) async version of this function, see arun_on_dataset.

PARAMETER DESCRIPTION
dataset_name

Name of the dataset to run the chain on.

TYPE: str

llm_or_chain_factory

Language model or Chain constructor to run over the dataset. The Chain constructor is used to permit independent calls on each example without carrying over state.

TYPE: MODEL_OR_CHAIN_FACTORY

evaluation

Configuration for evaluators to run on the results of the chain.

TYPE: RunEvalConfig | None DEFAULT: None

dataset_version

Optional version of the dataset.

TYPE: datetime | str | None DEFAULT: None

concurrency_level

The number of async tasks to run concurrently.

TYPE: int DEFAULT: 5

project_name

Name of the project to store the traces in. Defaults to {dataset_name}-{chain class name}-{datetime}.

TYPE: str | None DEFAULT: None

project_metadata

Optional metadata to add to the project. Useful for storing information the test variant. (prompt version, model version, etc.)

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

client

LangSmith client to use to access the dataset and to log feedback and run traces.

TYPE: Client | None

verbose

Whether to print progress.

TYPE: bool DEFAULT: False

revision_id

Optional revision identifier to assign this test run to track the performance of different versions of your system.

TYPE: str | None DEFAULT: None

**kwargs

Should not be used, but is provided for backwards compatibility.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
dict[str, Any]

dict containing the run's project name and the resulting model outputs.

Examples:

from langsmith import Client
from langchain_openai import ChatOpenAI
from langchain_classic.chains import LLMChain
from langchain_classic.smith import smith_eval.RunEvalConfig, run_on_dataset

# Chains may have memory. Passing in a constructor function lets the
# evaluation framework avoid cross-contamination between runs.
def construct_chain():
    model = ChatOpenAI(temperature=0)
    chain = LLMChain.from_string(
        model,
        "What's the answer to {your_input_key}"
    )
    return chain

# Load off-the-shelf evaluators via config or the EvaluatorType (string or enum)
evaluation_config = smith_eval.RunEvalConfig(
    evaluators=[
        "qa",  # "Correctness" against a reference answer
        "embedding_distance",
        smith_eval.RunEvalConfig.Criteria("helpfulness"),
        smith_eval.RunEvalConfig.Criteria({
            "fifth-grader-score": "Do you have to be smarter than a fifth "
            "grader to answer this question?"
        }),
    ]
)

client = Client()
run_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)

You can also create custom evaluators by subclassing the StringEvaluator or LangSmith's RunEvaluator classes.

from typing import Optional
from langchain_classic.evaluation import StringEvaluator


class MyStringEvaluator(StringEvaluator):
    @property
    def requires_input(self) -> bool:
        return False

    @property
    def requires_reference(self) -> bool:
        return True

    @property
    def evaluation_name(self) -> str:
        return "exact_match"

    def _evaluate_strings(
        self, prediction, reference=None, input=None, **kwargs
    ) -> dict:
        return {"score": prediction == reference}


evaluation_config = smith_eval.RunEvalConfig(
    custom_evaluators=[MyStringEvaluator()],
)

run_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)

langchain_classic.smith.evaluation.config

Configuration for run evaluators.

EvalConfig

Bases: BaseModel

Configuration for a given run evaluator.

ATTRIBUTE DESCRIPTION
evaluator_type

The type of evaluator to use.

TYPE: EvaluatorType

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

get_kwargs

get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

RunEvalConfig

Bases: BaseModel

Configuration for a run evaluation.

evaluators class-attribute instance-attribute

evaluators: list[SINGLE_EVAL_CONFIG_TYPE | CUSTOM_EVALUATOR_TYPE] = Field(
    default_factory=list
)

Configurations for which evaluators to apply to the dataset run. Each can be the string of an EvaluatorType <langchain.evaluation.schema.EvaluatorType>, such as EvaluatorType.QA, the evaluator type string ("qa"), or a configuration for a given evaluator (e.g., RunEvalConfig.QA <langchain.smith.evaluation.config.RunEvalConfig.QA>).

custom_evaluators class-attribute instance-attribute

custom_evaluators: list[CUSTOM_EVALUATOR_TYPE] | None = None

Custom evaluators to apply to the dataset run.

batch_evaluators class-attribute instance-attribute

batch_evaluators: list[BATCH_EVALUATOR_LIKE] | None = None

Evaluators that run on an aggregate/batch level.

These generate one or more metrics that are assigned to the full test run. As a result, they are not associated with individual traces.

reference_key class-attribute instance-attribute

reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute

prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute

input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

eval_llm class-attribute instance-attribute

eval_llm: BaseLanguageModel | None = None

The language model to pass to any evaluators that require one.

Criteria

Bases: SingleKeyEvalConfig

Configuration for a reference-free criteria evaluator.

ATTRIBUTE DESCRIPTION
criteria

The criteria to evaluate.

TYPE: CRITERIA_TYPE | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

LabeledCriteria

Bases: SingleKeyEvalConfig

Configuration for a labeled (with references) criteria evaluator.

ATTRIBUTE DESCRIPTION
criteria

The criteria to evaluate.

TYPE: CRITERIA_TYPE | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

EmbeddingDistance

Bases: SingleKeyEvalConfig

Configuration for an embedding distance evaluator.

ATTRIBUTE DESCRIPTION
embeddings

The embeddings to use for computing the distance.

TYPE: Embeddings | None

distance_metric

The distance metric to use for computing the distance.

TYPE: EmbeddingDistance | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

StringDistance

Bases: SingleKeyEvalConfig

Configuration for a string distance evaluator.

ATTRIBUTE DESCRIPTION
distance

The string distance metric to use (damerau_levenshtein, levenshtein, jaro, or jaro_winkler).

TYPE: StringDistance | None

normalize_score

Whether to normalize the distance to between 0 and 1. Applies only to the Levenshtein and Damerau-Levenshtein distances.

TYPE: bool

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

QA

Bases: SingleKeyEvalConfig

Configuration for a QA evaluator.

ATTRIBUTE DESCRIPTION
prompt

The prompt template to use for generating the question.

TYPE: BasePromptTemplate | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

ContextQA

Bases: SingleKeyEvalConfig

Configuration for a context-based QA evaluator.

ATTRIBUTE DESCRIPTION
prompt

The prompt template to use for generating the question.

TYPE: BasePromptTemplate | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

CoTQA

Bases: SingleKeyEvalConfig

Configuration for a context-based QA evaluator.

ATTRIBUTE DESCRIPTION
prompt

The prompt template to use for generating the question.

TYPE: BasePromptTemplate | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

JsonValidity

Bases: SingleKeyEvalConfig

Configuration for a json validity evaluator.

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

JsonEqualityEvaluator

Bases: EvalConfig

Configuration for a json equality evaluator.

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

ExactMatch

Bases: SingleKeyEvalConfig

Configuration for an exact match string evaluator.

ATTRIBUTE DESCRIPTION
ignore_case

Whether to ignore case when comparing strings.

TYPE: bool

ignore_punctuation

Whether to ignore punctuation when comparing strings.

TYPE: bool

ignore_numbers

Whether to ignore numbers when comparing strings.

TYPE: bool

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

RegexMatch

Bases: SingleKeyEvalConfig

Configuration for a regex match string evaluator.

ATTRIBUTE DESCRIPTION
flags

The flags to pass to the regex. Example: re.IGNORECASE.

TYPE: int

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

ScoreString

Bases: SingleKeyEvalConfig

Configuration for a score string evaluator.

This is like the criteria evaluator but it is configured by default to return a score on the scale from 1-10.

It is recommended to normalize these scores by setting normalize_by to 10.

ATTRIBUTE DESCRIPTION
criteria

The criteria to evaluate.

TYPE: CRITERIA_TYPE | None

llm

The language model to use for the evaluation chain.

TYPE: BaseLanguageModel | None

normalize_by

If you want to normalize the score, the denominator to use. If not provided, the score will be between 1 and 10.

TYPE: float | None

prompt

The prompt template to use for evaluation.

TYPE: BasePromptTemplate | None

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

LabeledScoreString

Bases: ScoreString

Configuration for a labeled score string evaluator.

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute
reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute
prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute
input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs
get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

SingleKeyEvalConfig

Bases: EvalConfig

Configuration for a run evaluator that only requires a single key.

METHOD DESCRIPTION
get_kwargs

Get the keyword arguments for the load_evaluator call.

reference_key class-attribute instance-attribute

reference_key: str | None = None

The key in the dataset run to use as the reference string. If not provided, we will attempt to infer automatically.

prediction_key class-attribute instance-attribute

prediction_key: str | None = None

The key from the traced run's outputs dictionary to use to represent the prediction. If not provided, it will be inferred automatically.

input_key class-attribute instance-attribute

input_key: str | None = None

The key from the traced run's inputs dictionary to use to represent the input. If not provided, it will be inferred automatically.

get_kwargs

get_kwargs() -> dict[str, Any]

Get the keyword arguments for the load_evaluator call.

RETURNS DESCRIPTION
dict[str, Any]

The keyword arguments for the load_evaluator call.

langchain_classic.smith.evaluation.progress

A simple progress bar for the console.

ProgressBarCallback

Bases: BaseCallbackHandler

A simple progress bar for the console.

METHOD DESCRIPTION
__init__

Initialize the progress bar.

increment

Increment the counter and update the progress bar.

on_chain_error

Run when chain errors.

on_chain_end

Run when chain ends running.

on_retriever_error

Run when Retriever errors.

on_retriever_end

Run when Retriever ends running.

on_llm_error

Run when LLM errors.

on_llm_end

Run when LLM ends running.

on_tool_error

Run when tool errors.

on_tool_end

Run when the tool ends running.

on_text

Run on an arbitrary text.

on_retry

Run on a retry event.

on_custom_event

Override to define a handler for a custom event.

on_llm_start

Run when LLM starts running.

on_chat_model_start

Run when a chat model starts running.

on_retriever_start

Run when the Retriever starts running.

on_chain_start

Run when a chain starts running.

on_tool_start

Run when the tool starts running.

on_agent_action

Run on agent action.

on_agent_finish

Run on the agent end.

on_llm_new_token

Run on new output token. Only available when streaming is enabled.

raise_error class-attribute instance-attribute

raise_error: bool = False

Whether to raise an error if an exception occurs.

run_inline class-attribute instance-attribute

run_inline: bool = False

Whether to run the callback inline.

ignore_llm property

ignore_llm: bool

Whether to ignore LLM callbacks.

ignore_retry property

ignore_retry: bool

Whether to ignore retry callbacks.

ignore_chain property

ignore_chain: bool

Whether to ignore chain callbacks.

ignore_agent property

ignore_agent: bool

Whether to ignore agent callbacks.

ignore_retriever property

ignore_retriever: bool

Whether to ignore retriever callbacks.

ignore_chat_model property

ignore_chat_model: bool

Whether to ignore chat model callbacks.

ignore_custom_event property

ignore_custom_event: bool

Ignore custom event.

__init__

__init__(total: int, ncols: int = 50, end_with: str = '\n')

Initialize the progress bar.

PARAMETER DESCRIPTION
total

The total number of items to be processed.

TYPE: int

ncols

The character width of the progress bar.

TYPE: int DEFAULT: 50

end_with

Last string to print after progress bar reaches end.

TYPE: str DEFAULT: '\n'

**kwargs

Additional keyword arguments.

increment

increment() -> None

Increment the counter and update the progress bar.

on_chain_error

on_chain_error(
    error: BaseException,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run when chain errors.

PARAMETER DESCRIPTION
error

The error that occurred.

TYPE: BaseException

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_chain_end

on_chain_end(
    outputs: dict[str, Any],
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run when chain ends running.

PARAMETER DESCRIPTION
outputs

The outputs of the chain.

TYPE: dict[str, Any]

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_retriever_error

on_retriever_error(
    error: BaseException,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run when Retriever errors.

PARAMETER DESCRIPTION
error

The error that occurred.

TYPE: BaseException

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_retriever_end

on_retriever_end(
    documents: Sequence[Document],
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run when Retriever ends running.

PARAMETER DESCRIPTION
documents

The documents retrieved.

TYPE: Sequence[Document]

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_llm_error

on_llm_error(
    error: BaseException,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run when LLM errors.

PARAMETER DESCRIPTION
error

The error that occurred.

TYPE: BaseException

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_llm_end

on_llm_end(
    response: LLMResult,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run when LLM ends running.

PARAMETER DESCRIPTION
response

The response which was generated.

TYPE: LLMResult

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_tool_error

on_tool_error(
    error: BaseException,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run when tool errors.

PARAMETER DESCRIPTION
error

The error that occurred.

TYPE: BaseException

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_tool_end

on_tool_end(
    output: str, *, run_id: UUID, parent_run_id: UUID | None = None, **kwargs: Any
) -> Any

Run when the tool ends running.

PARAMETER DESCRIPTION
output

The output of the tool.

TYPE: Any

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_text

on_text(
    text: str, *, run_id: UUID, parent_run_id: UUID | None = None, **kwargs: Any
) -> Any

Run on an arbitrary text.

PARAMETER DESCRIPTION
text

The text.

TYPE: str

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_retry

on_retry(
    retry_state: RetryCallState,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run on a retry event.

PARAMETER DESCRIPTION
retry_state

The retry state.

TYPE: RetryCallState

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_custom_event

on_custom_event(
    name: str,
    data: Any,
    *,
    run_id: UUID,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Override to define a handler for a custom event.

PARAMETER DESCRIPTION
name

The name of the custom event.

TYPE: str

data

The data for the custom event. Format will match the format specified by the user.

TYPE: Any

run_id

The ID of the run.

TYPE: UUID

tags

The tags associated with the custom event (includes inherited tags).

TYPE: list[str] | None DEFAULT: None

metadata

The metadata associated with the custom event (includes inherited metadata).

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

on_llm_start

on_llm_start(
    serialized: dict[str, Any],
    prompts: list[str],
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Run when LLM starts running.

Warning

This method is called for non-chat models (regular LLMs). If you're implementing a handler for a chat model, you should use on_chat_model_start instead.

PARAMETER DESCRIPTION
serialized

The serialized LLM.

TYPE: dict[str, Any]

prompts

The prompts.

TYPE: list[str]

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

tags

The tags.

TYPE: list[str] | None DEFAULT: None

metadata

The metadata.

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

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_chat_model_start

on_chat_model_start(
    serialized: dict[str, Any],
    messages: list[list[BaseMessage]],
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Run when a chat model starts running.

Warning

This method is called for chat models. If you're implementing a handler for a non-chat model, you should use on_llm_start instead.

PARAMETER DESCRIPTION
serialized

The serialized chat model.

TYPE: dict[str, Any]

messages

The messages.

TYPE: list[list[BaseMessage]]

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

tags

The tags.

TYPE: list[str] | None DEFAULT: None

metadata

The metadata.

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

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_retriever_start

on_retriever_start(
    serialized: dict[str, Any],
    query: str,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Run when the Retriever starts running.

PARAMETER DESCRIPTION
serialized

The serialized Retriever.

TYPE: dict[str, Any]

query

The query.

TYPE: str

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

tags

The tags.

TYPE: list[str] | None DEFAULT: None

metadata

The metadata.

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

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_chain_start

on_chain_start(
    serialized: dict[str, Any],
    inputs: dict[str, Any],
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Run when a chain starts running.

PARAMETER DESCRIPTION
serialized

The serialized chain.

TYPE: dict[str, Any]

inputs

The inputs.

TYPE: dict[str, Any]

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

tags

The tags.

TYPE: list[str] | None DEFAULT: None

metadata

The metadata.

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

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_tool_start

on_tool_start(
    serialized: dict[str, Any],
    input_str: str,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    inputs: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Run when the tool starts running.

PARAMETER DESCRIPTION
serialized

The serialized chain.

TYPE: dict[str, Any]

input_str

The input string.

TYPE: str

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

tags

The tags.

TYPE: list[str] | None DEFAULT: None

metadata

The metadata.

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

inputs

The inputs.

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

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_agent_action

on_agent_action(
    action: AgentAction,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run on agent action.

PARAMETER DESCRIPTION
action

The agent action.

TYPE: AgentAction

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_agent_finish

on_agent_finish(
    finish: AgentFinish,
    *,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run on the agent end.

PARAMETER DESCRIPTION
finish

The agent finish.

TYPE: AgentFinish

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

on_llm_new_token

on_llm_new_token(
    token: str,
    *,
    chunk: GenerationChunk | ChatGenerationChunk | None = None,
    run_id: UUID,
    parent_run_id: UUID | None = None,
    **kwargs: Any,
) -> Any

Run on new output token. Only available when streaming is enabled.

For both chat models and non-chat models (legacy LLMs).

PARAMETER DESCRIPTION
token

The new token.

TYPE: str

chunk

The new generated chunk, containing content and other information.

TYPE: GenerationChunk | ChatGenerationChunk | None DEFAULT: None

run_id

The run ID. This is the ID of the current run.

TYPE: UUID

parent_run_id

The parent run ID. This is the ID of the parent run.

TYPE: UUID | None DEFAULT: None

**kwargs

Additional keyword arguments.

TYPE: Any DEFAULT: {}

langchain_classic.smith.evaluation.runner_utils

Utilities for running language models or Chains over datasets.

FUNCTION DESCRIPTION
arun_on_dataset

Run on dataset.

run_on_dataset

Run on dataset.

ChatModelInput

Bases: TypedDict

Input for a chat model.

PARAMETER DESCRIPTION
messages

List of chat messages.

EvalError

Bases: dict

Your architecture raised an error.

METHOD DESCRIPTION
__init__

Initialize the EvalError with an error and additional attributes.

__getattr__

Get an attribute from the EvalError.

__init__

__init__(Error: BaseException, **kwargs: Any) -> None

Initialize the EvalError with an error and additional attributes.

PARAMETER DESCRIPTION
Error

The error that occurred.

TYPE: BaseException

**kwargs

Additional attributes to include in the error.

TYPE: Any DEFAULT: {}

__getattr__

__getattr__(name: str) -> Any

Get an attribute from the EvalError.

PARAMETER DESCRIPTION
name

The name of the attribute to get.

TYPE: str

RETURNS DESCRIPTION
Any

The value of the attribute.

RAISES DESCRIPTION
AttributeError

If the attribute does not exist.

InputFormatError

Bases: Exception

Raised when the input format is invalid.

TestResult

Bases: dict

A dictionary of the results of a single test run.

METHOD DESCRIPTION
get_aggregate_feedback

Return quantiles for the feedback scores.

to_dataframe

Convert the results to a dataframe.

get_aggregate_feedback

get_aggregate_feedback() -> DataFrame

Return quantiles for the feedback scores.

This method calculates and prints the quantiles for the feedback scores across all feedback keys.

RETURNS DESCRIPTION
DataFrame

A DataFrame containing the quantiles for each feedback key.

to_dataframe

to_dataframe() -> DataFrame

Convert the results to a dataframe.

arun_on_dataset async

arun_on_dataset(
    client: Client | None,
    dataset_name: str,
    llm_or_chain_factory: MODEL_OR_CHAIN_FACTORY,
    *,
    evaluation: RunEvalConfig | None = None,
    dataset_version: datetime | str | None = None,
    concurrency_level: int = 5,
    project_name: str | None = None,
    project_metadata: dict[str, Any] | None = None,
    verbose: bool = False,
    revision_id: str | None = None,
    **kwargs: Any,
) -> dict[str, Any]

Run on dataset.

Run the Chain or language model on a dataset and store traces to the specified project name.

For the (usually faster) async version of this function, see arun_on_dataset.

PARAMETER DESCRIPTION
dataset_name

Name of the dataset to run the chain on.

TYPE: str

llm_or_chain_factory

Language model or Chain constructor to run over the dataset. The Chain constructor is used to permit independent calls on each example without carrying over state.

TYPE: MODEL_OR_CHAIN_FACTORY

evaluation

Configuration for evaluators to run on the results of the chain.

TYPE: RunEvalConfig | None DEFAULT: None

dataset_version

Optional version of the dataset.

TYPE: datetime | str | None DEFAULT: None

concurrency_level

The number of async tasks to run concurrently.

TYPE: int DEFAULT: 5

project_name

Name of the project to store the traces in. Defaults to {dataset_name}-{chain class name}-{datetime}.

TYPE: str | None DEFAULT: None

project_metadata

Optional metadata to add to the project. Useful for storing information the test variant. (prompt version, model version, etc.)

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

client

LangSmith client to use to access the dataset and to log feedback and run traces.

TYPE: Client | None

verbose

Whether to print progress.

TYPE: bool DEFAULT: False

revision_id

Optional revision identifier to assign this test run to track the performance of different versions of your system.

TYPE: str | None DEFAULT: None

**kwargs

Should not be used, but is provided for backwards compatibility.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
dict[str, Any]

dict containing the run's project name and the resulting model outputs.

Examples:

from langsmith import Client
from langchain_openai import ChatOpenAI
from langchain_classic.chains import LLMChain
from langchain_classic.smith import smith_eval.RunEvalConfig, run_on_dataset

# Chains may have memory. Passing in a constructor function lets the
# evaluation framework avoid cross-contamination between runs.
def construct_chain():
    model = ChatOpenAI(temperature=0)
    chain = LLMChain.from_string(
        model,
        "What's the answer to {your_input_key}"
    )
    return chain

# Load off-the-shelf evaluators via config or the EvaluatorType (string or enum)
evaluation_config = smith_eval.RunEvalConfig(
    evaluators=[
        "qa",  # "Correctness" against a reference answer
        "embedding_distance",
        smith_eval.RunEvalConfig.Criteria("helpfulness"),
        smith_eval.RunEvalConfig.Criteria({
            "fifth-grader-score": "Do you have to be smarter than a fifth "
            "grader to answer this question?"
        }),
    ]
)

client = Client()
await arun_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)
You can also create custom evaluators by subclassing the StringEvaluator or LangSmith'sRunEvaluator` classes.

from typing import Optional
from langchain_classic.evaluation import StringEvaluator


class MyStringEvaluator(StringEvaluator):
    @property
    def requires_input(self) -> bool:
        return False

    @property
    def requires_reference(self) -> bool:
        return True

    @property
    def evaluation_name(self) -> str:
        return "exact_match"

    def _evaluate_strings(
        self, prediction, reference=None, input=None, **kwargs
    ) -> dict:
        return {"score": prediction == reference}


evaluation_config = smith_eval.RunEvalConfig(
    custom_evaluators=[MyStringEvaluator()],
)

await arun_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)

run_on_dataset

run_on_dataset(
    client: Client | None,
    dataset_name: str,
    llm_or_chain_factory: MODEL_OR_CHAIN_FACTORY,
    *,
    evaluation: RunEvalConfig | None = None,
    dataset_version: datetime | str | None = None,
    concurrency_level: int = 5,
    project_name: str | None = None,
    project_metadata: dict[str, Any] | None = None,
    verbose: bool = False,
    revision_id: str | None = None,
    **kwargs: Any,
) -> dict[str, Any]

Run on dataset.

Run the Chain or language model on a dataset and store traces to the specified project name.

For the (usually faster) async version of this function, see arun_on_dataset.

PARAMETER DESCRIPTION
dataset_name

Name of the dataset to run the chain on.

TYPE: str

llm_or_chain_factory

Language model or Chain constructor to run over the dataset. The Chain constructor is used to permit independent calls on each example without carrying over state.

TYPE: MODEL_OR_CHAIN_FACTORY

evaluation

Configuration for evaluators to run on the results of the chain.

TYPE: RunEvalConfig | None DEFAULT: None

dataset_version

Optional version of the dataset.

TYPE: datetime | str | None DEFAULT: None

concurrency_level

The number of async tasks to run concurrently.

TYPE: int DEFAULT: 5

project_name

Name of the project to store the traces in. Defaults to {dataset_name}-{chain class name}-{datetime}.

TYPE: str | None DEFAULT: None

project_metadata

Optional metadata to add to the project. Useful for storing information the test variant. (prompt version, model version, etc.)

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

client

LangSmith client to use to access the dataset and to log feedback and run traces.

TYPE: Client | None

verbose

Whether to print progress.

TYPE: bool DEFAULT: False

revision_id

Optional revision identifier to assign this test run to track the performance of different versions of your system.

TYPE: str | None DEFAULT: None

**kwargs

Should not be used, but is provided for backwards compatibility.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
dict[str, Any]

dict containing the run's project name and the resulting model outputs.

Examples:

from langsmith import Client
from langchain_openai import ChatOpenAI
from langchain_classic.chains import LLMChain
from langchain_classic.smith import smith_eval.RunEvalConfig, run_on_dataset

# Chains may have memory. Passing in a constructor function lets the
# evaluation framework avoid cross-contamination between runs.
def construct_chain():
    model = ChatOpenAI(temperature=0)
    chain = LLMChain.from_string(
        model,
        "What's the answer to {your_input_key}"
    )
    return chain

# Load off-the-shelf evaluators via config or the EvaluatorType (string or enum)
evaluation_config = smith_eval.RunEvalConfig(
    evaluators=[
        "qa",  # "Correctness" against a reference answer
        "embedding_distance",
        smith_eval.RunEvalConfig.Criteria("helpfulness"),
        smith_eval.RunEvalConfig.Criteria({
            "fifth-grader-score": "Do you have to be smarter than a fifth "
            "grader to answer this question?"
        }),
    ]
)

client = Client()
run_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)

You can also create custom evaluators by subclassing the StringEvaluator or LangSmith's RunEvaluator classes.

from typing import Optional
from langchain_classic.evaluation import StringEvaluator


class MyStringEvaluator(StringEvaluator):
    @property
    def requires_input(self) -> bool:
        return False

    @property
    def requires_reference(self) -> bool:
        return True

    @property
    def evaluation_name(self) -> str:
        return "exact_match"

    def _evaluate_strings(
        self, prediction, reference=None, input=None, **kwargs
    ) -> dict:
        return {"score": prediction == reference}


evaluation_config = smith_eval.RunEvalConfig(
    custom_evaluators=[MyStringEvaluator()],
)

run_on_dataset(
    client,
    dataset_name="<my_dataset_name>",
    llm_or_chain_factory=construct_chain,
    evaluation=evaluation_config,
)

langchain_classic.smith.evaluation.string_run_evaluator

Run evaluator wrapper for string evaluators.

ChainStringRunMapper

Bases: StringRunMapper

Extract items to evaluate from the run object from a chain.

METHOD DESCRIPTION
map

Maps the Run to a dictionary.

__init__
is_lc_serializable

Is this class serializable?

get_lc_namespace

Get the namespace of the LangChain object.

lc_id

Return a unique identifier for this class for serialization purposes.

to_json

Serialize the object to JSON.

to_json_not_implemented

Serialize a "not implemented" object.

__call__

Maps the Run to a dictionary.

input_key class-attribute instance-attribute

input_key: str | None = None

The key from the model Run's inputs to use as the eval input. If not provided, will use the only input key or raise an error if there are multiple.

prediction_key class-attribute instance-attribute

prediction_key: str | None = None

The key from the model Run's outputs to use as the eval prediction. If not provided, will use the only output key or raise an error if there are multiple.

lc_secrets property

lc_secrets: dict[str, str]

A map of constructor argument names to secret ids.

For example, {"openai_api_key": "OPENAI_API_KEY"}

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.

output_keys property

output_keys: list[str]

The keys to extract from the run.

map

map(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

__init__

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

is_lc_serializable classmethod

is_lc_serializable() -> bool

Is this class serializable?

By design, even if a class inherits from Serializable, it is not serializable by default. This is to prevent accidental serialization of objects that should not be serialized.

RETURNS DESCRIPTION
bool

Whether the class is serializable. Default is False.

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

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

RETURNS DESCRIPTION
list[str]

The namespace.

lc_id classmethod

lc_id() -> list[str]

Return a unique identifier for this class for serialization purposes.

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

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

to_json

to_json() -> SerializedConstructor | SerializedNotImplemented

Serialize the object to JSON.

RAISES DESCRIPTION
ValueError

If the class has deprecated attributes.

RETURNS DESCRIPTION
SerializedConstructor | SerializedNotImplemented

A JSON serializable object or a SerializedNotImplemented object.

to_json_not_implemented

to_json_not_implemented() -> SerializedNotImplemented

Serialize a "not implemented" object.

RETURNS DESCRIPTION
SerializedNotImplemented

SerializedNotImplemented.

__call__

__call__(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

LLMStringRunMapper

Bases: StringRunMapper

Extract items to evaluate from the run object.

METHOD DESCRIPTION
serialize_chat_messages

Extract the input messages from the run.

serialize_inputs

Serialize inputs.

serialize_outputs

Serialize outputs.

map

Maps the Run to a dictionary.

__init__
is_lc_serializable

Is this class serializable?

get_lc_namespace

Get the namespace of the LangChain object.

lc_id

Return a unique identifier for this class for serialization purposes.

to_json

Serialize the object to JSON.

to_json_not_implemented

Serialize a "not implemented" object.

__call__

Maps the Run to a dictionary.

lc_secrets property

lc_secrets: dict[str, str]

A map of constructor argument names to secret ids.

For example, {"openai_api_key": "OPENAI_API_KEY"}

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.

output_keys property

output_keys: list[str]

The keys to extract from the run.

serialize_chat_messages

serialize_chat_messages(messages: list[dict] | list[list[dict]]) -> str

Extract the input messages from the run.

serialize_inputs

serialize_inputs(inputs: dict) -> str

Serialize inputs.

PARAMETER DESCRIPTION
inputs

The inputs from the run, expected to contain prompts or messages.

TYPE: dict

RETURNS DESCRIPTION
str

The serialized input text from the prompts or messages.

RAISES DESCRIPTION
ValueError

If neither prompts nor messages are found in the inputs.

serialize_outputs

serialize_outputs(outputs: dict) -> str

Serialize outputs.

PARAMETER DESCRIPTION
outputs

The outputs from the run, expected to contain generations.

TYPE: dict

RETURNS DESCRIPTION
str

The serialized output text from the first generation.

RAISES DESCRIPTION
ValueError

If no generations are found in the outputs,

map

map(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

__init__

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

is_lc_serializable classmethod

is_lc_serializable() -> bool

Is this class serializable?

By design, even if a class inherits from Serializable, it is not serializable by default. This is to prevent accidental serialization of objects that should not be serialized.

RETURNS DESCRIPTION
bool

Whether the class is serializable. Default is False.

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

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

RETURNS DESCRIPTION
list[str]

The namespace.

lc_id classmethod

lc_id() -> list[str]

Return a unique identifier for this class for serialization purposes.

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

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

to_json

to_json() -> SerializedConstructor | SerializedNotImplemented

Serialize the object to JSON.

RAISES DESCRIPTION
ValueError

If the class has deprecated attributes.

RETURNS DESCRIPTION
SerializedConstructor | SerializedNotImplemented

A JSON serializable object or a SerializedNotImplemented object.

to_json_not_implemented

to_json_not_implemented() -> SerializedNotImplemented

Serialize a "not implemented" object.

RETURNS DESCRIPTION
SerializedNotImplemented

SerializedNotImplemented.

__call__

__call__(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

StringExampleMapper

Bases: Serializable

Map an example, or row in the dataset, to the inputs of an evaluation.

METHOD DESCRIPTION
serialize_chat_messages

Extract the input messages from the run.

map

Maps the Example, or dataset row to a dictionary.

__call__

Maps the Run and Example to a dictionary.

__init__
is_lc_serializable

Is this class serializable?

get_lc_namespace

Get the namespace of the LangChain object.

lc_id

Return a unique identifier for this class for serialization purposes.

to_json

Serialize the object to JSON.

to_json_not_implemented

Serialize a "not implemented" object.

output_keys property

output_keys: list[str]

The keys to extract from the run.

lc_secrets property

lc_secrets: dict[str, str]

A map of constructor argument names to secret ids.

For example, {"openai_api_key": "OPENAI_API_KEY"}

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.

serialize_chat_messages

serialize_chat_messages(messages: list[dict]) -> str

Extract the input messages from the run.

map

map(example: Example) -> dict[str, str]

Maps the Example, or dataset row to a dictionary.

__call__

__call__(example: Example) -> dict[str, str]

Maps the Run and Example to a dictionary.

__init__

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

is_lc_serializable classmethod

is_lc_serializable() -> bool

Is this class serializable?

By design, even if a class inherits from Serializable, it is not serializable by default. This is to prevent accidental serialization of objects that should not be serialized.

RETURNS DESCRIPTION
bool

Whether the class is serializable. Default is False.

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

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

RETURNS DESCRIPTION
list[str]

The namespace.

lc_id classmethod

lc_id() -> list[str]

Return a unique identifier for this class for serialization purposes.

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

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

to_json

to_json() -> SerializedConstructor | SerializedNotImplemented

Serialize the object to JSON.

RAISES DESCRIPTION
ValueError

If the class has deprecated attributes.

RETURNS DESCRIPTION
SerializedConstructor | SerializedNotImplemented

A JSON serializable object or a SerializedNotImplemented object.

to_json_not_implemented

to_json_not_implemented() -> SerializedNotImplemented

Serialize a "not implemented" object.

RETURNS DESCRIPTION
SerializedNotImplemented

SerializedNotImplemented.

StringRunEvaluatorChain

Bases: Chain, RunEvaluator

Evaluate Run and optional examples.

METHOD DESCRIPTION
evaluate_run

Evaluate an example.

aevaluate_run

Evaluate an example.

from_run_and_data_type

Create a StringRunEvaluatorChain.

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__
is_lc_serializable

Is this class serializable?

get_lc_namespace

Get the namespace of the LangChain object.

lc_id

Return a unique identifier for this class for serialization purposes.

to_json

Serialize the Runnable to JSON.

to_json_not_implemented

Serialize a "not implemented" object.

configurable_fields

Configure particular Runnable fields at runtime.

configurable_alternatives

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

raise_callback_manager_deprecation

Raise deprecation warning if callback_manager is used.

set_verbose

Set the chain verbosity.

__call__

Execute the chain.

acall

Asynchronously execute the chain.

prep_outputs

Validate and prepare chain outputs, and save info about this run to memory.

aprep_outputs

Validate and prepare chain outputs, and save info about this run to memory.

prep_inputs

Prepare chain inputs, including adding inputs from memory.

aprep_inputs

Prepare chain inputs, including adding inputs from memory.

run

Convenience method for executing chain.

arun

Convenience method for executing chain.

dict

Dictionary representation of chain.

save

Save the chain.

apply

Call the chain on all inputs in the list.

run_mapper instance-attribute

run_mapper: StringRunMapper

Maps the Run to a dictionary with 'input' and 'prediction' strings.

example_mapper class-attribute instance-attribute

example_mapper: StringExampleMapper | None = None

Maps the Example (dataset row) to a dictionary with a 'reference' string.

name instance-attribute

name: str

The name of the evaluation metric.

string_evaluator instance-attribute

string_evaluator: StringEvaluator

The evaluation chain.

input_keys property

input_keys: list[str]

Keys expected to be in the chain input.

output_keys property

output_keys: list[str]

Keys expected to be in the chain output.

InputType property

InputType: type[Input]

Input type.

The type of input this Runnable accepts specified as a type annotation.

RAISES DESCRIPTION
TypeError

If the input type cannot be inferred.

OutputType property

OutputType: type[Output]

Output Type.

The type of output this Runnable produces specified as a type annotation.

RAISES DESCRIPTION
TypeError

If the output type cannot be inferred.

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_secrets property

lc_secrets: dict[str, str]

A map of constructor argument names to secret ids.

For example, {"openai_api_key": "OPENAI_API_KEY"}

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.

memory class-attribute instance-attribute

memory: BaseMemory | None = None

Optional memory object. Memory is a class that gets called at the start and at the end of every chain. At the start, memory loads variables and passes them along in the chain. At the end, it saves any returned variables. There are many different types of memory - please see memory docs for the full catalog.

callbacks class-attribute instance-attribute

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

Optional list of callback handlers (or callback manager). Callback handlers are called throughout the lifecycle of a call to a chain, starting with on_chain_start, ending with on_chain_end or on_chain_error. Each custom chain can optionally call additional callback methods, see Callback docs for full details.

verbose class-attribute instance-attribute

verbose: bool = Field(default_factory=_get_verbosity)

Whether or not run in verbose mode. In verbose mode, some intermediate logs will be printed to the console. Defaults to the global verbose value, accessible via langchain.globals.get_verbose().

tags class-attribute instance-attribute

tags: list[str] | None = None

Optional list of tags associated with the chain. These tags will be associated with each call to this chain, and passed as arguments to the handlers defined in callbacks. You can use these to eg identify a specific instance of a chain with its use case.

metadata class-attribute instance-attribute

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

Optional metadata associated with the chain. This metadata will be associated with each call to this chain, and passed as arguments to the handlers defined in callbacks. You can use these to eg identify a specific instance of a chain with its use case.

callback_manager class-attribute instance-attribute

callback_manager: BaseCallbackManager | None = Field(default=None, exclude=True)

[DEPRECATED] Use callbacks instead.

evaluate_run

evaluate_run(
    run: Run, example: Example | None = None, evaluator_run_id: UUID | None = None
) -> EvaluationResult

Evaluate an example.

aevaluate_run async

aevaluate_run(
    run: Run, example: Example | None = None, evaluator_run_id: UUID | None = None
) -> EvaluationResult

Evaluate an example.

from_run_and_data_type classmethod

from_run_and_data_type(
    evaluator: StringEvaluator,
    run_type: str,
    data_type: DataType,
    input_key: str | None = None,
    prediction_key: str | None = None,
    reference_key: str | None = None,
    tags: list[str] | None = None,
) -> StringRunEvaluatorChain

Create a StringRunEvaluatorChain.

Create a StringRunEvaluatorChain from an evaluator and the run and dataset types.

This method provides an easy way to instantiate a StringRunEvaluatorChain, by taking an evaluator and information about the type of run and the data. The method supports LLM and chain runs.

PARAMETER DESCRIPTION
evaluator

The string evaluator to use.

TYPE: StringEvaluator

run_type

The type of run being evaluated. Supported types are LLM and Chain.

TYPE: str

data_type

The type of dataset used in the run.

TYPE: DataType

input_key

The key used to map the input from the run.

TYPE: str | None DEFAULT: None

prediction_key

The key used to map the prediction from the run.

TYPE: str | None DEFAULT: None

reference_key

The key used to map the reference from the dataset.

TYPE: str | None DEFAULT: None

tags

List of tags to attach to the evaluation chain.

TYPE: list[str] | None DEFAULT: None

RETURNS DESCRIPTION
StringRunEvaluatorChain

The instantiated evaluation chain.

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: dict[str, Any], config: RunnableConfig | None = None, **kwargs: Any
) -> dict[str, Any]

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: dict[str, Any], config: RunnableConfig | None = None, **kwargs: Any
) -> dict[str, Any]

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

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

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

is_lc_serializable classmethod

is_lc_serializable() -> bool

Is this class serializable?

By design, even if a class inherits from Serializable, it is not serializable by default. This is to prevent accidental serialization of objects that should not be serialized.

RETURNS DESCRIPTION
bool

Whether the class is serializable. Default is False.

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

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

RETURNS DESCRIPTION
list[str]

The namespace.

lc_id classmethod

lc_id() -> list[str]

Return a unique identifier for this class for serialization purposes.

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

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

to_json

to_json() -> SerializedConstructor | SerializedNotImplemented

Serialize the Runnable to JSON.

RETURNS DESCRIPTION
SerializedConstructor | SerializedNotImplemented

A JSON-serializable representation of the Runnable.

to_json_not_implemented

to_json_not_implemented() -> SerializedNotImplemented

Serialize a "not implemented" object.

RETURNS DESCRIPTION
SerializedNotImplemented

SerializedNotImplemented.

configurable_fields

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

Configure particular Runnable fields at runtime.

PARAMETER DESCRIPTION
**kwargs

A dictionary of ConfigurableField instances to configure.

TYPE: AnyConfigurableField DEFAULT: {}

RAISES DESCRIPTION
ValueError

If a configuration key is not found in the Runnable.

RETURNS DESCRIPTION
RunnableSerializable[Input, Output]

A new Runnable with the fields configured.

from langchain_core.runnables import ConfigurableField
from langchain_openai import ChatOpenAI

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

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

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

configurable_alternatives

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

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

PARAMETER DESCRIPTION
which

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

TYPE: ConfigurableField

default_key

The default key to use if no alternative is selected.

TYPE: str DEFAULT: 'default'

prefix_keys

Whether to prefix the keys with the ConfigurableField id.

TYPE: bool DEFAULT: False

**kwargs

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

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

RETURNS DESCRIPTION
RunnableSerializable[Input, Output]

A new Runnable with the alternatives configured.

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

model = ChatAnthropic(
    model_name="claude-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
)

raise_callback_manager_deprecation classmethod

raise_callback_manager_deprecation(values: dict) -> Any

Raise deprecation warning if callback_manager is used.

set_verbose classmethod

set_verbose(verbose: bool | None) -> bool

Set the chain verbosity.

Defaults to the global setting if not specified by the user.

__call__

__call__(
    inputs: dict[str, Any] | Any,
    return_only_outputs: bool = False,
    callbacks: Callbacks = None,
    *,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    run_name: str | None = None,
    include_run_info: bool = False,
) -> dict[str, Any]

Execute the chain.

PARAMETER DESCRIPTION
inputs

Dictionary of inputs, or single input if chain expects only one param. Should contain all inputs specified in Chain.input_keys except for inputs that will be set by the chain's memory.

TYPE: dict[str, Any] | Any

return_only_outputs

Whether to return only outputs in the response. If True, only new keys generated by this chain will be returned. If False, both input keys and new keys generated by this chain will be returned.

TYPE: bool DEFAULT: False

callbacks

Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

TYPE: Callbacks DEFAULT: None

tags

List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

TYPE: list[str] | None DEFAULT: None

metadata

Optional metadata associated with the chain.

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

run_name

Optional name for this run of the chain.

TYPE: str | None DEFAULT: None

include_run_info

Whether to include run info in the response. Defaults to False.

TYPE: bool DEFAULT: False

RETURNS DESCRIPTION
dict[str, Any]

A dict of named outputs. Should contain all outputs specified in Chain.output_keys.

acall async

acall(
    inputs: dict[str, Any] | Any,
    return_only_outputs: bool = False,
    callbacks: Callbacks = None,
    *,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    run_name: str | None = None,
    include_run_info: bool = False,
) -> dict[str, Any]

Asynchronously execute the chain.

PARAMETER DESCRIPTION
inputs

Dictionary of inputs, or single input if chain expects only one param. Should contain all inputs specified in Chain.input_keys except for inputs that will be set by the chain's memory.

TYPE: dict[str, Any] | Any

return_only_outputs

Whether to return only outputs in the response. If True, only new keys generated by this chain will be returned. If False, both input keys and new keys generated by this chain will be returned.

TYPE: bool DEFAULT: False

callbacks

Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

TYPE: Callbacks DEFAULT: None

tags

List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

TYPE: list[str] | None DEFAULT: None

metadata

Optional metadata associated with the chain.

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

run_name

Optional name for this run of the chain.

TYPE: str | None DEFAULT: None

include_run_info

Whether to include run info in the response. Defaults to False.

TYPE: bool DEFAULT: False

RETURNS DESCRIPTION
dict[str, Any]

A dict of named outputs. Should contain all outputs specified in Chain.output_keys.

prep_outputs

prep_outputs(
    inputs: dict[str, str], outputs: dict[str, str], return_only_outputs: bool = False
) -> dict[str, str]

Validate and prepare chain outputs, and save info about this run to memory.

PARAMETER DESCRIPTION
inputs

Dictionary of chain inputs, including any inputs added by chain memory.

TYPE: dict[str, str]

outputs

Dictionary of initial chain outputs.

TYPE: dict[str, str]

return_only_outputs

Whether to only return the chain outputs. If False, inputs are also added to the final outputs.

TYPE: bool DEFAULT: False

RETURNS DESCRIPTION
dict[str, str]

A dict of the final chain outputs.

aprep_outputs async

aprep_outputs(
    inputs: dict[str, str], outputs: dict[str, str], return_only_outputs: bool = False
) -> dict[str, str]

Validate and prepare chain outputs, and save info about this run to memory.

PARAMETER DESCRIPTION
inputs

Dictionary of chain inputs, including any inputs added by chain memory.

TYPE: dict[str, str]

outputs

Dictionary of initial chain outputs.

TYPE: dict[str, str]

return_only_outputs

Whether to only return the chain outputs. If False, inputs are also added to the final outputs.

TYPE: bool DEFAULT: False

RETURNS DESCRIPTION
dict[str, str]

A dict of the final chain outputs.

prep_inputs

prep_inputs(inputs: dict[str, Any] | Any) -> dict[str, str]

Prepare chain inputs, including adding inputs from memory.

PARAMETER DESCRIPTION
inputs

Dictionary of raw inputs, or single input if chain expects only one param. Should contain all inputs specified in Chain.input_keys except for inputs that will be set by the chain's memory.

TYPE: dict[str, Any] | Any

RETURNS DESCRIPTION
dict[str, str]

A dictionary of all inputs, including those added by the chain's memory.

aprep_inputs async

aprep_inputs(inputs: dict[str, Any] | Any) -> dict[str, str]

Prepare chain inputs, including adding inputs from memory.

PARAMETER DESCRIPTION
inputs

Dictionary of raw inputs, or single input if chain expects only one param. Should contain all inputs specified in Chain.input_keys except for inputs that will be set by the chain's memory.

TYPE: dict[str, Any] | Any

RETURNS DESCRIPTION
dict[str, str]

A dictionary of all inputs, including those added by the chain's memory.

run

run(
    *args: Any,
    callbacks: Callbacks = None,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Convenience method for executing chain.

The main difference between this method and Chain.__call__ is that this method expects inputs to be passed directly in as positional arguments or keyword arguments, whereas Chain.__call__ expects a single input dictionary with all the inputs

PARAMETER DESCRIPTION
*args

If the chain expects a single input, it can be passed in as the sole positional argument.

TYPE: Any DEFAULT: ()

callbacks

Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

TYPE: Callbacks DEFAULT: None

tags

List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

TYPE: list[str] | None DEFAULT: None

metadata

Optional metadata associated with the chain.

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

**kwargs

If the chain expects multiple inputs, they can be passed in directly as keyword arguments.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
Any

The chain output.

Example
# Suppose we have a single-input chain that takes a 'question' string:
chain.run("What's the temperature in Boise, Idaho?")
# -> "The temperature in Boise is..."

# Suppose we have a multi-input chain that takes a 'question' string
# and 'context' string:
question = "What's the temperature in Boise, Idaho?"
context = "Weather report for Boise, Idaho on 07/03/23..."
chain.run(question=question, context=context)
# -> "The temperature in Boise is..."

arun async

arun(
    *args: Any,
    callbacks: Callbacks = None,
    tags: list[str] | None = None,
    metadata: dict[str, Any] | None = None,
    **kwargs: Any,
) -> Any

Convenience method for executing chain.

The main difference between this method and Chain.__call__ is that this method expects inputs to be passed directly in as positional arguments or keyword arguments, whereas Chain.__call__ expects a single input dictionary with all the inputs

PARAMETER DESCRIPTION
*args

If the chain expects a single input, it can be passed in as the sole positional argument.

TYPE: Any DEFAULT: ()

callbacks

Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

TYPE: Callbacks DEFAULT: None

tags

List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

TYPE: list[str] | None DEFAULT: None

metadata

Optional metadata associated with the chain.

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

**kwargs

If the chain expects multiple inputs, they can be passed in directly as keyword arguments.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
Any

The chain output.

Example
# Suppose we have a single-input chain that takes a 'question' string:
await chain.arun("What's the temperature in Boise, Idaho?")
# -> "The temperature in Boise is..."

# Suppose we have a multi-input chain that takes a 'question' string
# and 'context' string:
question = "What's the temperature in Boise, Idaho?"
context = "Weather report for Boise, Idaho on 07/03/23..."
await chain.arun(question=question, context=context)
# -> "The temperature in Boise is..."

dict

dict(**kwargs: Any) -> dict

Dictionary representation of chain.

Expects Chain._chain_type property to be implemented and for memory to be null.

PARAMETER DESCRIPTION
**kwargs

Keyword arguments passed to default pydantic.BaseModel.dict method.

TYPE: Any DEFAULT: {}

RETURNS DESCRIPTION
dict

A dictionary representation of the chain.

Example
chain.model_dump(exclude_unset=True)
# -> {"_type": "foo", "verbose": False, ...}

save

save(file_path: Path | str) -> None

Save the chain.

Expects Chain._chain_type property to be implemented and for memory to be null.

PARAMETER DESCRIPTION
file_path

Path to file to save the chain to.

TYPE: Path | str

Example
chain.save(file_path="path/chain.yaml")

apply

apply(
    input_list: list[dict[str, Any]], callbacks: Callbacks = None
) -> list[dict[str, str]]

Call the chain on all inputs in the list.

StringRunMapper

Bases: Serializable

Extract items to evaluate from the run object.

METHOD DESCRIPTION
map

Maps the Run to a dictionary.

__call__

Maps the Run to a dictionary.

__init__
is_lc_serializable

Is this class serializable?

get_lc_namespace

Get the namespace of the LangChain object.

lc_id

Return a unique identifier for this class for serialization purposes.

to_json

Serialize the object to JSON.

to_json_not_implemented

Serialize a "not implemented" object.

output_keys property

output_keys: list[str]

The keys to extract from the run.

lc_secrets property

lc_secrets: dict[str, str]

A map of constructor argument names to secret ids.

For example, {"openai_api_key": "OPENAI_API_KEY"}

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.

map abstractmethod

map(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

__call__

__call__(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

__init__

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

is_lc_serializable classmethod

is_lc_serializable() -> bool

Is this class serializable?

By design, even if a class inherits from Serializable, it is not serializable by default. This is to prevent accidental serialization of objects that should not be serialized.

RETURNS DESCRIPTION
bool

Whether the class is serializable. Default is False.

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

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

RETURNS DESCRIPTION
list[str]

The namespace.

lc_id classmethod

lc_id() -> list[str]

Return a unique identifier for this class for serialization purposes.

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

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

to_json

to_json() -> SerializedConstructor | SerializedNotImplemented

Serialize the object to JSON.

RAISES DESCRIPTION
ValueError

If the class has deprecated attributes.

RETURNS DESCRIPTION
SerializedConstructor | SerializedNotImplemented

A JSON serializable object or a SerializedNotImplemented object.

to_json_not_implemented

to_json_not_implemented() -> SerializedNotImplemented

Serialize a "not implemented" object.

RETURNS DESCRIPTION
SerializedNotImplemented

SerializedNotImplemented.

ToolStringRunMapper

Bases: StringRunMapper

Map an input to the tool.

METHOD DESCRIPTION
map

Maps the Run to a dictionary.

__init__
is_lc_serializable

Is this class serializable?

get_lc_namespace

Get the namespace of the LangChain object.

lc_id

Return a unique identifier for this class for serialization purposes.

to_json

Serialize the object to JSON.

to_json_not_implemented

Serialize a "not implemented" object.

__call__

Maps the Run to a dictionary.

lc_secrets property

lc_secrets: dict[str, str]

A map of constructor argument names to secret ids.

For example, {"openai_api_key": "OPENAI_API_KEY"}

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.

output_keys property

output_keys: list[str]

The keys to extract from the run.

map

map(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

__init__

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

is_lc_serializable classmethod

is_lc_serializable() -> bool

Is this class serializable?

By design, even if a class inherits from Serializable, it is not serializable by default. This is to prevent accidental serialization of objects that should not be serialized.

RETURNS DESCRIPTION
bool

Whether the class is serializable. Default is False.

get_lc_namespace classmethod

get_lc_namespace() -> list[str]

Get the namespace of the LangChain object.

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

RETURNS DESCRIPTION
list[str]

The namespace.

lc_id classmethod

lc_id() -> list[str]

Return a unique identifier for this class for serialization purposes.

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

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

to_json

to_json() -> SerializedConstructor | SerializedNotImplemented

Serialize the object to JSON.

RAISES DESCRIPTION
ValueError

If the class has deprecated attributes.

RETURNS DESCRIPTION
SerializedConstructor | SerializedNotImplemented

A JSON serializable object or a SerializedNotImplemented object.

to_json_not_implemented

to_json_not_implemented() -> SerializedNotImplemented

Serialize a "not implemented" object.

RETURNS DESCRIPTION
SerializedNotImplemented

SerializedNotImplemented.

__call__

__call__(run: Run) -> dict[str, str]

Maps the Run to a dictionary.

langchain_classic.smith.evaluation.name_generation

FUNCTION DESCRIPTION
random_name

Generate a random name.

random_name

random_name() -> str

Generate a random name.