@runbit/anthropic

An Anthropic (Claude) ChatModel for Runbit. Zero dependencies — uses global fetch.

npm install @runbit/anthropic @runbit/runtime

import { anthropic } from "@runbit/anthropic";
import { agent } from "@runbit/runtime";

const model = anthropic("claude-sonnet-5"); // reads ANTHROPIC_API_KEY
const assistant = agent({ model, tools: [weather] });

Options

anthropic("claude-sonnet-5", {
  apiKey: process.env.ANTHROPIC_API_KEY, // default
  baseURL: "https://api.anthropic.com/v1",
  maxTokens: 1024,   // Anthropic requires a limit
  temperature: 0.7,
  version: "2023-06-01", // anthropic-version header
});

Pick any current model id from Anthropic's model list — e.g. claude-sonnet-5, claude-opus-4-8, or claude-haiku-4-5-20251001 for a cheaper option.

Supports tool calling and reports token usage, so @runbit/devtools can show cost. Pass the result straight to agent({ model }) — because the agent only knows ChatModel, switching from OpenAI to Claude is a one-line change.

Part of Runbit — the AI Runtime. Providers ship separately so you install only what you use.

• Umbrella: @runbit/runtime
• License: MIT