A tool that can be created dynamically from a function, name, and description, designed to work with structured data. It extends the StructuredTool class and overrides the _call method to execute the provided function when the tool is called.

Schema can be passed as Zod or JSON schema. The tool will not validate input if JSON schema is passed.

Type Parameters

  • T extends ZodObjectAny | Record<string, any> = ZodObjectAny

Hierarchy (view full)

  • StructuredTool<T extends ZodObjectAny
        ? T
        : ZodObjectAny>
    • DynamicStructuredTool

Constructors

Properties

description: string
func: ((input: T extends ZodObjectAny
    ? TypeOf<T<T>>
    : T, runManager?: CallbackManagerForToolRun, config?: RunnableConfig) => Promise<any>)
name: string
returnDirect: boolean = false
schema: T extends ZodObjectAny
    ? T<T>
    : ZodObjectAny
verbose: boolean

Whether to print out response text.

callbacks?: Callbacks
metadata?: Record<string, unknown>
responseFormat?: string = "content"

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"
tags?: string[]

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 ZodObjectAny
              ? T<T>
              : ZodObjectAny> extends string
          ? string
          : never) | input<T extends ZodObjectAny
          ? T<T>
          : ZodObjectAny>

    Parameters

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

      • 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.

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

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

  • 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 ZodObjectAny
              ? T<T>
              : ZodObjectAny> extends string
          ? string
          : never) | input<T extends ZodObjectAny
          ? T<T>
          : ZodObjectAny>)[]

      Array of inputs to each batch call.

    • Optionaloptions: Partial<RunnableConfig> | Partial<RunnableConfig>[]

      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 ZodObjectAny
              ? T<T>
              : ZodObjectAny> extends string
          ? string
          : never) | input<T extends ZodObjectAny
          ? T<T>
          : ZodObjectAny>)[]
    • Optionaloptions: Partial<RunnableConfig> | Partial<RunnableConfig>[]
    • OptionalbatchOptions: RunnableBatchOptions & {
          returnExceptions: true;
      }

    Returns Promise<any[]>

  • Parameters

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

    Returns Promise<any[]>

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

    Parameters

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

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

  • Invokes the tool with the provided input and configuration.

    Parameters

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

      The input for the tool.

    • Optionalconfig: RunnableConfig

      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 ZodObjectAny
            ? T<T>
            : ZodObjectAny> extends string
        ? string
        : never) | input<T extends ZodObjectAny
        ? T<T>
        : ZodObjectAny>)[], any[], RunnableConfig>

  • 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

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

    A new runnable sequence.

  • 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:

    Parameters

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

    Returns IterableReadableStream<StreamEvent>

    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 ZodObjectAny
              ? T<T>
              : ZodObjectAny> extends string
          ? string
          : never) | input<T extends ZodObjectAny
          ? T<T>
          : ZodObjectAny>
    • options: Partial<RunnableConfig> & {
          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 ZodObjectAny
              ? T<T>
              : ZodObjectAny> extends string
          ? string
          : never) | input<T extends ZodObjectAny
          ? T<T>
          : ZodObjectAny>
    • Optionaloptions: Partial<RunnableConfig>
    • OptionalstreamOptions: Omit<LogStreamCallbackHandlerInput, "autoClose">

    Returns AsyncGenerator<RunLogPatch, any, unknown>

  • 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 ZodObjectAny
              ? T<T>
              : ZodObjectAny> extends string
          ? string
          : never) | input<T extends ZodObjectAny
          ? T<T>
          : ZodObjectAny>, any, unknown>
    • options: Partial<RunnableConfig>

    Returns AsyncGenerator<any, any, unknown>

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

    Returns RunnableWithFallbacks<ToolCall | (output<T extends ZodObjectAny
            ? T<T>
            : ZodObjectAny> extends string
        ? string
        : never) | input<T extends ZodObjectAny
        ? T<T>
        : ZodObjectAny>, 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) => void | Promise<void>);
          onError?: ((run: Run, config?: RunnableConfig) => void | Promise<void>);
          onStart?: ((run: Run, config?: RunnableConfig) => void | Promise<void>);
      }

      The object containing the callback functions.

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

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

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

            Returns void | Promise<void>

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

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

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

            Returns void | Promise<void>

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

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

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

            Returns void | Promise<void>

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