ADK-TSTools
Create Tool
Create custom tools from functions with `createTool`.
The createTool function provides a convenient way to create a tool from a function. This method handles the boilerplate of creating a tool class and instance for you.
Usage
To create a tool, you pass a configuration object to the createTool function. The function should be well-documented with JSDoc comments, as this information is used by the LLM to understand how to use the tool.
import { AgentBuilder } from "@adk/agents";
import { createTool } from "@adk/tools";
import { z } from "zod";
/**
* A simple tool that adds two numbers.
* @param a The first number.
* @param b The second number.
* @returns The sum of the two numbers.
*/
const add = (a: number, b: number) => a + b;
const { runner } = await AgentBuilder.create("calculator-agent")
.withModel("gemini-2.5-flash")
.withTools(createTool({
name: "add",
description: "Adds two numbers.",
schema: z.object({
a: z.number(),
b: z.number(),
}),
fn: add,
}))
.build();
const result = await runner.ask("What is 2 + 2?");Parameters
The createTool function accepts a configuration object with the following properties:
name: The name of the tool.description: A description of what the tool does.fn: The function to be converted into a tool.schema(optional): A Zod schema that defines the input parameters for the tool.isLongRunning(optional): A boolean indicating if the tool performs a long-running operation. Defaults tofalse.shouldRetryOnFailure(optional): A boolean indicating if the tool should be retried on failure. Defaults tofalse.maxRetryAttempts(optional): The maximum number of retry attempts. Defaults to3.
Advanced Usage
Here is an example that uses the optional parameters:
import { AgentBuilder } from "@adk/agents";
import { createTool } from "@adk/tools";
import { z } from "zod";
/**
* A tool that simulates a long-running task.
* @returns A message indicating the task is complete.
*/
const longRunningTask = async () => {
await new Promise(resolve => setTimeout(resolve, 5000));
return "Long running task complete!";
}
const { runner } = await AgentBuilder.create("long-running-agent")
.withModel("gemini-2.5-flash")
.withTools(createTool({
name: "longRunningTask",
description: "A tool that simulates a long-running task.",
fn: longRunningTask,
isLongRunning: true,
shouldRetryOnFailure: true,
maxRetryAttempts: 5,
}))
.build();
const result = await runner.ask("Run the long running task.");How is this guide?