claude-function-ts

Function calling sdk for claude in typescript (supports JSONSchema)

Installation

You need to install the anthropic-sdk as well to use this sdk.

npm add claude-function-ts @anthropic-ai/sdk
yarn add claude-function-ts @anthropic-ai/sdk
pnpm add claude-function-ts @anthropic-ai/sdk
bun add claude-function-ts @anthropic-ai/sdk

Quick start (with Anthropic sdk)

import { Anthropic } from 'claude-function-ts';

const anthropic = new Anthropic({
  apiKey: "YOUR_API_KEY",
});

const resp = await anthropic.tools
  .create(
    [
    //  ...JSONSchema
    ] as const,
    {
      model: "claude-3-haiku-20240307",
      stream: false,
      max_tokens: 2000,
      messages: [
        {
          role: "user",
          content:
            "Send an email to rahul,zack and malay from scalar.video, I want to talk to him about how they built their CRDTs for their video editor; I am reaching out cold",
        },
      ],
    }
  )
  .manual();

Wrap Anthropic SDK

import {withTools} from 'claude-function-ts';
import {Anthropic} from '@anthropic/anthropic-sdk';

const anthropic = new Anthropic({
  apiKey: "YOUR_API_KEY",
});

const tools = withTools(anthropic);

tools.create(...)

API

Tools definition

Would recommend using something like zod to generate the json schema for the tools.

.tools.create(tool: Tool[], message: MessageParams, options: RequestOptions)

export type Tool = {
  name: Readonly<string>;
  description: string;
  parameters: JSONSchema;
};

Manual

Manual will just give you the output of one single function call, it will return either the assistant response or the tool inputs for your function call.

.tools.create(...).manual({forceFunctionCall = false}: {forceFunctionCall: boolean}): Promise<
      Result<
        | { role: "assistant"; content: string }
        | { role: "tool_inputs"; content?: string; tool_inputs: ToolInput[] },
        string
      >>;

export type ToolInput = {
  tool_name: string;
  tool_arguments: unknown;
};

• the forceFunctionCall will ensure the model ends with a function call but forcing the stop sequence

Automatic

Automatic will keep calling the assistant with the function results till the assistant stops the conversation.

.tools.create(...).automatic(cb: {
    [toolName: string] : (params: unknown): Promise<{}> | {}
}): Promise<
      Result<
        { role: "assistant"; content: string },
        string
      >
    >

In automatic mode you need to ensure you have the tool callbacks for the tools you are using in the conversation.

• if you use as const while defining the tools, you can use the toolNames and the params will be properly typed in the callback.

Example

Automatic Code Example

Disclaimer

I think the anthropic function calling api is kinda jank and this doesn't strictly follow it, sorta diverges to enable easy arrays and objects in the xml output. I expect to that the xml parsing here isn't perfect and happy to accept PRs to improve it.

This is based on the alpha-sdk for function calling from anthropic here