@chai-ai/anthropic

The @chai-ai/anthropic package provides the adapter layer for connecting Chai AI agents to Anthropic's Claude models using the official @anthropic-ai/sdk Node SDK. Under the hood, this uses the modern Messages API structure.

Installation

Ensure you have installed the Anthropic provider package alongside chai-ai:

npm install @chai-ai/anthropic

Authentication

The provider automatically reads the Anthropic API Key from the environment:

export ANTHROPIC_API_KEY="your-anthropic-api-key"

API Reference

anthropic(modelId)

Creates a LanguageModel descriptor for an Anthropic model.

• Parameters:
  • modelId: string — The identifier of the Anthropic model (e.g., "claude-haiku-4-5", "claude-3-5-sonnet-20241022").
• Returns: LanguageModel interface instance.

import { Agent } from "chai-ai";
import { anthropic } from "@chai-ai/anthropic";

const model = anthropic("claude-haiku-4-5");

const agent = new Agent({
  name: "claude-agent",
  instructions: "You are an Anthropic-powered assistant.",
  model,
});

Features & Implementation Details

• Messages API Integration: Maps message history structures directly onto the Anthropic Messages API (client.messages.create).
• Consecutive Message Coalescing: Anthropic's API strictly enforces alternating user/assistant roles. Consecutive tool execution results or user corrections are automatically coalesced into single message blocks by the adapter to prevent validation errors.
• Client-Side Cancellation: Fully threads abort signals (AbortSignal) into the request configuration context to terminate in-flight connections on timeout.
• Token Usage Mapping: Translates token counts from the Anthropic SDK events into standard Chai AI SDK TokenUsage metrics, calculating total tokens as input_tokens + output_tokens.