Class StructuredTool<T>Abstract

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

Type Parameters

  • T extends z.ZodObject<any, any, any, any> = z.ZodObject<any, any, any, any>

Hierarchy (view full)

Constructors

Properties

description: string
name: string
returnDirect: boolean = false
schema: T | ZodEffects<T, output<T>, input<T>>
verbose: boolean

Whether to print out response text.

callbacks?: CallbackManager | (BaseCallbackHandlerMethodsClass | BaseCallbackHandler)[]
metadata?: Record<string, unknown>
tags?: string[]

Methods

  • Parameters

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

      The input argument for the tool.

    • Optional configArg: CallbackManager | (BaseCallbackHandlerMethodsClass | BaseCallbackHandler)[] | RunnableConfig

      Optional configuration or callbacks for the tool.

    • Optional tags: string[]

      Optional tags for the tool.

    Returns Promise<string>

    A Promise that resolves with a string.

    ⚠️ Deprecated ⚠️

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

    This feature is deprecated and will be removed in the future.

    It is not recommended for use.

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

  • Invokes the tool with the provided input and configuration.

    Parameters

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

      The input for the tool.

    • Optional config: RunnableConfig

      Optional configuration for the tool.

    Returns Promise<string>

    A Promise that resolves with a string.

  • 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.

    event name chunk input output
    on_llm_start [model name] {'input': 'hello'}
    on_llm_stream [model name] 'Hello' OR AIMessageChunk("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_stream some_tool {"x": 1, "y": "2"}
    on_tool_end some_tool {"x": 1, "y": "2"}
    on_retriever_start [retriever name] {"query": "hello"}
    on_retriever_chunk [retriever name] {documents: [...]}
    on_retriever_end [retriever name] {"query": "hello"} {documents: [...]}
    on_prompt_start [template_name] {"question": "hello"}
    on_prompt_end [template_name] {"question": "hello"} ChatPromptValue(messages: [SystemMessage, ...])

    Parameters

    Returns AsyncGenerator<StreamEvent, any, unknown>

  • 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

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

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

        Other runnables to call if the runnable errors.

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

    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, config?) => void | Promise<void>);
          onError?: ((run, config?) => void | Promise<void>);
          onStart?: ((run, config?) => void | Promise<void>);
      }

      The object containing the callback functions.

      • Optional onEnd?: ((run, config?) => void | Promise<void>)

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

          • (run, config?): void | Promise<void>
          • Called after the runnable finishes running, with the Run object.

            Parameters

            Returns void | Promise<void>

      • Optional onError?: ((run, config?) => void | Promise<void>)

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

          • (run, config?): void | Promise<void>
          • Called if the runnable throws an error, with the Run object.

            Parameters

            Returns void | Promise<void>

      • Optional onStart?: ((run, config?) => void | Promise<void>)

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

          • (run, config?): void | Promise<void>
          • Called before the runnable starts running, with the Run object.

            Parameters

            Returns void | Promise<void>

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

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