A chain managing an agent using tools.

Example


const executor = AgentExecutor.fromAgentAndTools({
agent: async () => loadAgentFromLangchainHub(),
tools: [new SerpAPI(), new Calculator()],
returnIntermediateSteps: true,
});

const result = await executor.invoke({
input: `Who is Olivia Wilde's boyfriend? What is his current age raised to the 0.23 power?`,
});

Hierarchy

Constructors

Properties

earlyStoppingMethod: StoppingMethod = "force"
handleParsingErrors: string | boolean | ((e) => string) = false

How to handle errors raised by the agent's output parser. Defaults to False, which raises the error.

If true, the error will be sent back to the LLM as an observation. If a string, the string itself will be sent to the LLM as an observation. If a callable function, the function will be called with the exception as an argument, and the result of that function will be passed to the agent as an observation.

Type declaration

    • (e): string
    • Parameters

      • e: OutputParserException | ToolInputParsingException

      Returns string

returnIntermediateSteps: boolean = false
returnOnlyOutputs: boolean = true
tools: StructuredToolInterface<ZodObject<any, any, any, any, {}>>[]
verbose: boolean

Whether to print out response text.

callbacks?: Callbacks
maxIterations?: number = 15
memory?: BaseMemory
metadata?: Record<string, unknown>
name?: string
tags?: string[]

Accessors

  • get shouldContinueGetter(): ((iterations) => boolean)
  • Returns ((iterations) => boolean)

      • (iterations): boolean
      • Method that checks if the agent execution should continue based on the number of iterations.

        Parameters

        • iterations: number

          The current number of iterations.

        Returns boolean

        A boolean indicating whether the agent execution should continue.

Methods

  • 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>

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

    Parameters

    • inputs: ChainValues[]

      Array of inputs to each batch call.

    • Optional options: Partial<RunnableConfig> | Partial<RunnableConfig>[]

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

    • Optional batchOptions: RunnableBatchOptions & {
          returnExceptions?: false;
      }

    Returns Promise<ChainValues[]>

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

  • Parameters

    Returns Promise<(Error | ChainValues)[]>

  • Parameters

    Returns Promise<(Error | ChainValues)[]>

  • Parameters

    • values: ChainValues & {
          signal?: AbortSignal;
          timeout?: number;
      }
    • Optional config: RunnableConfig | Callbacks
    • Optional tags: string[]

      Deprecated

    Returns Promise<ChainValues>

    Deprecated

    Use .invoke() instead. Will be removed in 0.2.0.

    Run the core logic of this chain and add to output if desired.

    Wraps _call and handles memory.

  • Parameters

    • Optional suffix: string

    Returns string

  • 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<ChainValues, NewRunOutput>

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

    Returns Runnable<ChainValues, Exclude<NewRunOutput, Error>, RunnableConfig>

    A new runnable sequence.

  • Parameters

    • inputs: Record<string, unknown>
    • outputs: Record<string, unknown>
    • returnOnlyOutputs: boolean = false

    Returns Promise<Record<string, unknown>>

  • Stream output in chunks.

    Parameters

    Returns Promise<IterableReadableStream<ChainValues>>

    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.

    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

    • input: ChainValues
    • options: Partial<RunnableConfig> & {
          version: "v1";
      }
    • Optional streamOptions: Omit<LogStreamCallbackHandlerInput, "autoClose">

    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

    • input: ChainValues
    • Optional options: Partial<RunnableConfig>
    • Optional streamOptions: 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

    Returns AsyncGenerator<ChainValues, any, unknown>

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

            Parameters

            Returns void | Promise<void>

    Returns Runnable<ChainValues, ChainValues, RunnableConfig>

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