Class StructuredTool<T>Abstract

Base class for Tools that accept input of any shape defined by a Zod schema.

Type Parameters

  • T extends ZodObjectAny = ZodObjectAny

Hierarchy (view full)

Constructors

  • Type Parameters

    • T extends ZodObjectAny = ZodObjectAny

    Parameters

    Returns StructuredTool<T>

Properties

callbacks?: Callbacks
description: string
metadata?: Record<string, unknown>
name: string
responseFormat?: string

The tool response format.

If "content" then the output of the tool is interpreted as the contents of a ToolMessage. If "content_and_artifact" then the output is expected to be a two-tuple corresponding to the (content, artifact) of a ToolMessage.

"content"
returnDirect: boolean
schema: T | ZodEffects<T, output<T>, input<T>>
tags?: string[]
verbose: boolean

Whether to print out response text.

verboseParsingErrors: boolean

Methods

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

    Type Parameters

    • T extends string | ToolCall | {} = ToolCall | (output<T> extends string
          ? string
          : never) | input<T>

    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>, any>

    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: (ToolCall | (output<T> extends string
          ? string
          : never) | input<T>)[]

      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<any[]>

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

  • Parameters

    • inputs: (ToolCall | (output<T> extends string
          ? string
          : never) | input<T>)[]
    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>> | Partial<RunnableConfig<Record<string, any>>>[]
    • OptionalbatchOptions: RunnableBatchOptions & {
          returnExceptions: true;
      }

    Returns Promise<any[]>

  • Parameters

    • inputs: (ToolCall | (output<T> extends string
          ? string
          : never) | input<T>)[]
    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>> | Partial<RunnableConfig<Record<string, any>>>[]
    • OptionalbatchOptions: RunnableBatchOptions

    Returns Promise<any[]>

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

    Parameters

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

    Returns Runnable<ToolCall | (output<T> extends string
        ? string
        : never) | input<T>, any, RunnableConfig<Record<string, any>>>

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

  • Parameters

    • arg: input<T> | (output<T> extends string
          ? string
          : never)

      The input argument for the tool.

    • OptionalconfigArg: Callbacks | ToolRunnableConfig<Record<string, any>>

      Optional configuration or callbacks for the tool.

    • Optionaltags: string[]

      Optional tags for the tool.

    Returns Promise<any>

    A Promise that resolves with a string.

    Use .invoke() instead. Will be removed in 0.3.0.

    Calls the tool with the provided argument, configuration, and tags. It parses the input according to the schema, handles any errors, and manages callbacks.

  • Parameters

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

    Returns Graph

  • Parameters

    • Optionalsuffix: string

    Returns string

  • Invokes the tool with the provided input and configuration.

    Parameters

    • input: ToolCall | input<T> | (output<T> extends string
          ? string
          : never)

      The input for the tool.

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

      Optional configuration for the tool.

    Returns Promise<any>

    A Promise that resolves with a string.

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

    Returns Runnable<(ToolCall | (output<T> extends string
        ? string
        : never) | input<T>)[], any[], RunnableConfig<Record<string, any>>>

  • 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<any, NewRunOutput, RunnableConfig<Record<string, any>>>

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

    Returns Runnable<ToolCall | (output<T> extends string
        ? string
        : never) | input<T>, Exclude<NewRunOutput, Error>, RunnableConfig<Record<string, any>>>

    A new runnable sequence.

  • Stream output in chunks.

    Parameters

    • input: ToolCall | (output<T> extends string
          ? string
          : never) | input<T>
    • Optionaloptions: Partial<RunnableConfig<Record<string, any>>>

    Returns Promise<IterableReadableStream<any>>

    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                | input                       | output/chunk                             |
    +======================+=============================+==========================================+
    | on_chat_model_start  | {"messages": BaseMessage[]} |                                          |
    +----------------------+-----------------------------+------------------------------------------+
    | on_chat_model_stream |                             | AIMessageChunk("hello")                  |
    +----------------------+-----------------------------+------------------------------------------+
    | on_chat_model_end    | {"messages": BaseMessage[]} | AIMessageChunk("hello world")            |
    +----------------------+-----------------------------+------------------------------------------+
    | on_llm_start         | {'input': 'hello'}          |                                          |
    +----------------------+-----------------------------+------------------------------------------+
    | on_llm_stream        |                             | 'Hello'                                  |
    +----------------------+-----------------------------+------------------------------------------+
    | on_llm_end           | 'Hello human!'              |                                          |
    +----------------------+-----------------------------+------------------------------------------+
    | on_chain_start       |                             |                                          |
    +----------------------+-----------------------------+------------------------------------------+
    | on_chain_stream      |                             | "hello world!"                           |
    +----------------------+-----------------------------+------------------------------------------+
    | on_chain_end         | [Document(...)]             | "hello world!, goodbye world!"           |
    +----------------------+-----------------------------+------------------------------------------+
    | on_tool_start        | {"x": 1, "y": "2"}          |                                          |
    +----------------------+-----------------------------+------------------------------------------+
    | on_tool_end          |                             | {"x": 1, "y": "2"}                       |
    +----------------------+-----------------------------+------------------------------------------+
    | on_retriever_start   | {"query": "hello"}          |                                          |
    +----------------------+-----------------------------+------------------------------------------+
    | on_retriever_end     | {"query": "hello"}          | [Document(...), ..]                      |
    +----------------------+-----------------------------+------------------------------------------+
    | on_prompt_start      | {"question": "hello"}       |                                          |
    +----------------------+-----------------------------+------------------------------------------+
    | on_prompt_end        | {"question": "hello"}       | ChatPromptValue(messages: BaseMessage[]) |
    +----------------------+-----------------------------+------------------------------------------+
    

    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.  |
    +-----------+------+------------------------------------------------------------+
    

    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: ToolCall | (output<T> extends string
          ? string
          : never) | input<T>
    • options: Partial<RunnableConfig<Record<string, any>>> & {
          version: "v1" | "v2";
      }
    • OptionalstreamOptions: Omit<EventStreamCallbackHandlerInput, "autoClose">

    Returns IterableReadableStream<StreamEvent>

  • Parameters

    • input: ToolCall | (output<T> extends string
          ? string
          : never) | input<T>
    • 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: ToolCall | (output<T> extends string
          ? string
          : never) | input<T>
    • 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<ToolCall | (output<T> extends string
          ? string
          : never) | input<T>, any, unknown>
    • options: Partial<RunnableConfig<Record<string, any>>>

    Returns AsyncGenerator<any, 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 Runnable<ToolCall | (output<T> extends string
        ? string
        : never) | input<T>, any, 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<ToolCall | (output<T> extends string
              ? string
              : never) | input<T>, any, RunnableConfig<Record<string, any>>>[];
      } | Runnable<ToolCall | (output<T> extends string
          ? string
          : never) | input<T>, any, RunnableConfig<Record<string, any>>>[]

    Returns RunnableWithFallbacks<ToolCall | (output<T> extends string
        ? string
        : never) | input<T>, any>

    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<ToolCall | (output<T> extends string
        ? string
        : never) | input<T>, any, RunnableConfig<Record<string, any>>>

  • Add retry logic to an existing runnable.

    Parameters

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

    Returns RunnableRetry<ToolCall | (output<T> extends string
        ? string
        : never) | input<T>, any, RunnableConfig<Record<string, any>>>

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

  • Parameters

    • thing: any

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

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