Class CustomFormatPromptTemplate<RunInput, PartialVariableName>

Type Parameters

  • RunInput extends InputValues = any
  • PartialVariableName extends string = any

Hierarchy (view full)

Constructors

Properties

PromptValueReturnType: StringPromptValueInterface
additionalContentFields?: MessageContentComplex

Additional fields which should be included inside the message content array if using a complex message content.

inputVariables: Extract<keyof RunInput, string>[]

A list of variable names the prompt template expects

name?: string
outputParser?: BaseOutputParser<unknown>

How to parse the output of calling an LLM on this formatted prompt

partialVariables: PartialValues<PartialVariableName>

Partial variables

renderer: ((template: string, values: InputValues) => string)
template: MessageContent

The prompt template

templateFormat: TemplateFormat

The format of the prompt template. Options are "f-string" and "mustache"

templateValidator?: ((template: string, inputVariables: string[]) => boolean)
validateTemplate: boolean

Whether or not to try validating the template on initialization

true

Methods

  • Convert a runnable to a tool. Return a new instance of RunnableToolLike which contains the runnable, name, description and schema.

    Type Parameters

    Parameters

    • fields: {
          description?: string;
          name?: string;
          schema: ZodType<T, ZodTypeDef, T>;
      }
      • Optionaldescription?: string

        The description of the tool. Falls back to the description on the Zod schema if not provided, or undefined if neither are provided.

      • Optionalname?: string

        The name of the tool. If not provided, it will default to the name of the runnable.

      • schema: ZodType<T, ZodTypeDef, T>

        The Zod schema for the input of the tool. Infers the Zod type from the input type of the runnable.

    Returns RunnableToolLike<ZodType<ToolCall | T, ZodTypeDef, ToolCall | T>, StringPromptValueInterface>

    An instance of RunnableToolLike which is a runnable that can be used as a tool.

  • Assigns new fields to the dict output of this runnable. Returns a new runnable.

    Parameters

    • mapping: RunnableMapLike<Record<string, unknown>, Record<string, unknown>>

    Returns Runnable<any, any, RunnableConfig<Record<string, any>>>

  • Default implementation of batch, which calls invoke N times. Subclasses should override this method if they can batch more efficiently.

    Parameters

    • inputs: RunInput[]

      Array of inputs to each batch call.

    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>> | Partial<RunnableConfig<Record<string, any>>>[]

      Either a single call options object to apply to each batch call or an array for each call.

    • OptionalbatchOptions: RunnableBatchOptions & {
          returnExceptions?: false;
      }

    Returns Promise<StringPromptValueInterface[]>

    An array of RunOutputs, or mixed RunOutputs and errors if batchOptions.returnExceptions is set

  • Parameters

    • inputs: RunInput[]
    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>> | Partial<RunnableConfig<Record<string, any>>>[]
    • OptionalbatchOptions: RunnableBatchOptions & {
          returnExceptions: true;
      }

    Returns Promise<(Error | StringPromptValueInterface)[]>

  • Parameters

    • inputs: RunInput[]
    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>> | Partial<RunnableConfig<Record<string, any>>>[]
    • OptionalbatchOptions: RunnableBatchOptions

    Returns Promise<(Error | StringPromptValueInterface)[]>

  • Bind arguments to a Runnable, returning a new Runnable.

    Parameters

    • kwargs: Partial<RunnableConfig<Record<string, any>>>

    Returns Runnable<RunInput, StringPromptValueInterface, RunnableConfig<Record<string, any>>>

    A new RunnableBinding that, when invoked, will apply the bound args.

  • Formats the prompt template with the provided values.

    Parameters

    • values: TypedPromptInputValues<RunInput>

      The values to be used to format the prompt template.

    Returns Promise<string>

    A promise that resolves to a string which is the formatted prompt.

  • Formats the prompt given the input values and returns a formatted prompt value.

    Parameters

    • values: TypedPromptInputValues<RunInput>

      The input values to format the prompt.

    Returns Promise<StringPromptValueInterface>

    A Promise that resolves to a formatted prompt value.

  • Parameters

    • Optional_: RunnableConfig<Record<string, any>>

    Returns Graph

  • Parameters

    • Optionalsuffix: string

    Returns string

  • Invokes the prompt template with the given input and options.

    Parameters

    • input: RunInput

      The input to invoke the prompt template with.

    • Optionaloptions: BaseCallbackConfig

      Optional configuration for the callback.

    Returns Promise<StringPromptValueInterface>

    A Promise that resolves to the output of the prompt template.

  • Return a new Runnable that maps a list of inputs to a list of outputs, by calling invoke() with each input.

    Returns Runnable<RunInput[], StringPromptValueInterface[], RunnableConfig<Record<string, any>>>

  • Merges partial variables and user variables.

    Parameters

    • userVariables: TypedPromptInputValues<RunInput>

      The user variables to merge with the partial variables.

    Returns Promise<InputValues<PartialVariableName | Extract<keyof RunInput, string>>>

    A Promise that resolves to an object containing the merged variables.

  • Partially applies values to the prompt template.

    Type Parameters

    • NewPartialVariableName extends string

    Parameters

    Returns Promise<PromptTemplate<InputValues<Exclude<Extract<keyof RunInput, string>, NewPartialVariableName>>, any>>

    A new instance of PromptTemplate with the partially applied values.

  • Pick keys from the dict output of this runnable. Returns a new runnable.

    Parameters

    • keys: string | string[]

    Returns Runnable<any, any, RunnableConfig<Record<string, any>>>

  • Create a new runnable sequence that runs each individual runnable in series, piping the output of one runnable into another runnable or runnable-like.

    Type Parameters

    • NewRunOutput

    Parameters

    • coerceable: RunnableLike<StringPromptValueInterface, NewRunOutput, RunnableConfig<Record<string, any>>>

      A runnable, function, or object whose values are functions or runnables.

    Returns Runnable<RunInput, Exclude<NewRunOutput, Error>, RunnableConfig<Record<string, any>>>

    A new runnable sequence.

  • Return a json-like object representing this prompt template.

    Returns SerializedPromptTemplate

  • Stream output in chunks.

    Parameters

    • input: RunInput
    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>>

    Returns Promise<IterableReadableStream<StringPromptValueInterface>>

    A readable stream that is also an iterable.

  • Generate a stream of events emitted by the internal steps of the runnable.

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

    A StreamEvent is a dictionary with the following schema:

    • event: string - Event names are of the format: on_[runnable_type]_(start|stream|end).
    • name: string - The name of the runnable that generated the event.
    • run_id: string - 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.
    • tags: string[] - The tags of the runnable that generated the event.
    • metadata: Record<string, any> - The metadata of the runnable that generated the event.
    • data: Record<string, any>

    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.

    ATTENTION This reference table is for the V2 version of the schema.

    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | event                | name             | chunk                           | input                                         | output                                          |
    +======================+==================+=================================+===============================================+=================================================+
    | on_chat_model_start  | [model name]     |                                 | {"messages": [[SystemMessage, HumanMessage]]} |                                                 |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_chat_model_stream | [model name]     | AIMessageChunk(content="hello") |                                               |                                                 |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_chat_model_end    | [model name]     |                                 | {"messages": [[SystemMessage, HumanMessage]]} | AIMessageChunk(content="hello world")           |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_llm_start         | [model name]     |                                 | {'input': 'hello'}                            |                                                 |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_llm_stream        | [model name]     | 'Hello'                         |                                               |                                                 |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_llm_end           | [model name]     |                                 | 'Hello human!'                                |                                                 |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_chain_start       | some_runnable    |                                 |                                               |                                                 |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_chain_stream      | some_runnable    | "hello world!, goodbye world!"  |                                               |                                                 |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    | on_chain_end         | some_runnable    |                                 | [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, ...]) |
    +----------------------+------------------+---------------------------------+-----------------------------------------------+-------------------------------------------------+
    

    The "on_chain_*" events are the default for Runnables that don't fit one of the above categories.

    In addition to the standard events above, users can also dispatch custom events.

    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's an example:

    import { RunnableLambda } from "@langchain/core/runnables";
    import { dispatchCustomEvent } from "@langchain/core/callbacks/dispatch";
    // Use this import for web environments that don't support "async_hooks"
    // and manually pass config to child runs.
    // import { dispatchCustomEvent } from "@langchain/core/callbacks/dispatch/web";

    const slowThing = RunnableLambda.from(async (someInput: string) => {
    // Placeholder for some slow operation
    await new Promise((resolve) => setTimeout(resolve, 100));
    await dispatchCustomEvent("progress_event", {
    message: "Finished step 1 of 2",
    });
    await new Promise((resolve) => setTimeout(resolve, 100));
    return "Done";
    });

    const eventStream = await slowThing.streamEvents("hello world", {
    version: "v2",
    });

    for await (const event of eventStream) {
    if (event.event === "on_custom_event") {
    console.log(event);
    }
    }

    Parameters

    • input: RunInput
    • options: Partial<RunnableConfig<Record<string, any>>> & {
          version: "v1" | "v2";
      }
    • OptionalstreamOptions: Omit<EventStreamCallbackHandlerInput, "autoClose">

    Returns IterableReadableStream<StreamEvent>

  • Parameters

    • input: RunInput
    • options: Partial<RunnableConfig<Record<string, any>>> & {
          encoding: "text/event-stream";
          version: "v1" | "v2";
      }
    • OptionalstreamOptions: Omit<EventStreamCallbackHandlerInput, "autoClose">

    Returns IterableReadableStream<Uint8Array>

  • 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.

    Parameters

    • input: RunInput
    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>>
    • OptionalstreamOptions: Omit<LogStreamCallbackHandlerInput, "autoClose">

    Returns AsyncGenerator<RunLogPatch, any, unknown>

  • Returns Serialized

  • Default implementation of transform, which buffers input and then calls stream. Subclasses should override this method if they can start producing output while input is still being generated.

    Parameters

    • generator: AsyncGenerator<RunInput, any, unknown>
    • options: Partial<RunnableConfig<Record<string, any>>>

    Returns AsyncGenerator<StringPromptValueInterface, any, unknown>

  • Bind config to a Runnable, returning a new Runnable.

    Parameters

    • config: RunnableConfig<Record<string, any>>

      New configuration parameters to attach to the new runnable.

    Returns RunnableBinding<RunInput, StringPromptValueInterface, RunnableConfig<Record<string, any>>>

    A new RunnableBinding with a config matching what's passed.

  • Create a new runnable from the current one that will try invoking other passed fallback runnables if the initial invocation fails.

    Parameters

    • fields: {
          fallbacks: Runnable<RunInput, StringPromptValueInterface, RunnableConfig<Record<string, any>>>[];
      } | Runnable<RunInput, StringPromptValueInterface, RunnableConfig<Record<string, any>>>[]

    Returns RunnableWithFallbacks<RunInput, StringPromptValueInterface>

    A new RunnableWithFallbacks.

  • 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, startTime, endTime, and any tags or metadata added to the run.

    Parameters

    • params: {
          onEnd?: ((run: Run, config?: RunnableConfig<Record<string, any>>) => void | Promise<void>);
          onError?: ((run: Run, config?: RunnableConfig<Record<string, any>>) => void | Promise<void>);
          onStart?: ((run: Run, config?: RunnableConfig<Record<string, any>>) => void | Promise<void>);
      }

      The object containing the callback functions.

      • OptionalonEnd?: ((run: Run, config?: RunnableConfig<Record<string, any>>) => void | Promise<void>)

        Called after the runnable finishes running, with the Run object.

          • (run, config?): void | Promise<void>
          • Parameters

            • run: Run
            • Optionalconfig: RunnableConfig<Record<string, any>>

            Returns void | Promise<void>

      • OptionalonError?: ((run: Run, config?: RunnableConfig<Record<string, any>>) => void | Promise<void>)

        Called if the runnable throws an error, with the Run object.

          • (run, config?): void | Promise<void>
          • Parameters

            • run: Run
            • Optionalconfig: RunnableConfig<Record<string, any>>

            Returns void | Promise<void>

      • OptionalonStart?: ((run: Run, config?: RunnableConfig<Record<string, any>>) => void | Promise<void>)

        Called before the runnable starts running, with the Run object.

          • (run, config?): void | Promise<void>
          • Parameters

            • run: Run
            • Optionalconfig: RunnableConfig<Record<string, any>>

            Returns void | Promise<void>

    Returns Runnable<RunInput, StringPromptValueInterface, RunnableConfig<Record<string, any>>>

  • Add retry logic to an existing runnable.

    Parameters

    • Optionalfields: {
          onFailedAttempt?: RunnableRetryFailedAttemptHandler;
          stopAfterAttempt?: number;
      }
      • OptionalonFailedAttempt?: RunnableRetryFailedAttemptHandler
      • OptionalstopAfterAttempt?: number

    Returns RunnableRetry<RunInput, StringPromptValueInterface, RunnableConfig<Record<string, any>>>

    A new RunnableRetry that, when invoked, will retry according to the parameters.

  • Parameters

    • data: SerializedPromptTemplate

    Returns Promise<PromptTemplate<any, any>>

    Load a prompt template from a json-like object describing it.

    Deserializing needs to be async because templates (e.g. FewShotPromptTemplate) can reference remote resources that we read asynchronously with a web request.

  • Take examples in list format with prefix and suffix to create a prompt.

    Intended to be used a a way to dynamically create a prompt from examples.

    Parameters

    • examples: string[]

      List of examples to use in the prompt.

    • suffix: string

      String to go after the list of examples. Should generally set up the user's input.

    • inputVariables: string[]

      A list of variable names the final prompt template will expect

    • OptionalexampleSeparator: string

      The separator to use in between examples

    • Optionalprefix: string

      String that should go before any examples. Generally includes examples.

    Returns PromptTemplate<any, any>

    The final prompt template generated.

  • Parameters

    • thing: any

    Returns thing is Runnable<any, any, RunnableConfig<Record<string, any>>>