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