TypeScript

import { Schema, Tool, type ToolInput, type ToolOutput } from "agentc:tools";

agentc:tools provides the classes and types used to define and invoke a tool. See tools for the lifecycle shared by every tool.

Overview

Classes

Schema

new Schema(schema: Record<string, unknown>)

Validates a JSON Schema draft 2020-12 document for a tool's parameters.

Tool

abstract class Tool<Args, Result, State = unknown> {
  static readonly description?: string
  static readonly parameters: Schema

  abstract execute(input: ToolInput<Args, State>): Promise<ToolOutput<Result>>
}

The abstract base class for every tool. Export a subclass and select it with the manifest's export field. Its optional static description is the tool's description when the manifest's description is unset. Its static parameters supplies the model-facing input schema.

A subclass that does not implement execute rejects with a Tool subclass must implement execute. execute must return a promise.

ToolInput

class ToolInput<Args, State = unknown> {
  readonly args: Args
  readonly state: State
  readonly emit?: (delta: ActivityDelta) => void
}

The runtime creates one input for each invocation. Tool code cannot construct it.

Types

ToolOutput

type ToolOutput<Result> = {
  output: Result
  state_update?: PatchDocument
}

The value returned by execute. output is required. state_update is optional and contains RFC 6902 JSON Patch operations. For ReAct state updates, see state.

ActivityDelta

type ActivityDelta = {
  activity_type: string
  patch: PatchDocument
}

The value passed to input.emit?.(...). Its patch contains RFC 6902 JSON Patch operations.