Anthropic

Access 19 Anthropic models through Mastra's model router. Authentication is handled automatically using the ANTHROPIC_API_KEY environment variable.

Learn more in the Anthropic documentation.

ANTHROPIC_API_KEY=your-api-key

import { Agent } from "@mastra/core";

const agent = new Agent({
  name: "my-agent",
  instructions: "You are a helpful assistant",
  model: "anthropic/claude-3-5-haiku-20241022"
});

// Generate a response
const response = await agent.generate("Hello!");

// Stream a response
const stream = await agent.stream("Tell me a story");
for await (const chunk of stream) {
  console.log(chunk);
}

Models

Model	Image	Audio	Video	Tools	Streaming	Context Window
anthropic/claude-3-5-haiku-20241022	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-5-haiku-latest	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-5-sonnet-20240620	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-5-sonnet-20241022	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-7-sonnet-20250219	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-7-sonnet-latest	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-haiku-20240307	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-opus-20240229	✓	✗	✗	✓	✗	200,000
anthropic/claude-3-sonnet-20240229	✓	✗	✗	✓	✗	200,000
anthropic/claude-haiku-4-5	✓	✗	✗	✓	✗	200,000
anthropic/claude-haiku-4-5-20251001	✓	✗	✗	✓	✗	200,000
anthropic/claude-opus-4-0	✓	✗	✗	✓	✗	200,000
anthropic/claude-opus-4-1	✓	✗	✗	✓	✗	200,000
anthropic/claude-opus-4-1-20250805	✓	✗	✗	✓	✗	200,000
anthropic/claude-opus-4-20250514	✓	✗	✗	✓	✗	200,000
anthropic/claude-sonnet-4-0	✓	✗	✗	✓	✗	200,000
anthropic/claude-sonnet-4-20250514	✓	✗	✗	✓	✗	200,000
anthropic/claude-sonnet-4-5	✓	✗	✗	✓	✗	200,000
anthropic/claude-sonnet-4-5-20250929	✓	✗	✗	✓	✗	200,000

Advanced Configuration

Custom Headers

const agent = new Agent({
  name: "custom-agent",
  model: {
    id: "anthropic/claude-3-5-haiku-20241022",
    apiKey: process.env.ANTHROPIC_API_KEY,
    headers: {
      "X-Custom-Header": "value"
    }
  }
});

Dynamic Model Selection

const agent = new Agent({
  name: "dynamic-agent",
  model: ({ runtimeContext }) => {
    const useAdvanced = runtimeContext.task === "complex";
    return useAdvanced
      ? "anthropic/claude-sonnet-4-5-20250929"
      : "anthropic/claude-3-5-haiku-20241022";
  }
});

Provider Options

Anthropic supports the following provider-specific options via the providerOptions parameter:

const response = await agent.generate("Hello!", {
  providerOptions: {
    anthropic: {
      // See available options in the table below
    }
  }
});

Available Options

sendReasoning?:

boolean | undefined

thinking?:

{ type: "enabled" | "disabled"; budgetTokens?: number | undefined; } | undefined

disableParallelToolUse?:

boolean | undefined

cacheControl?:

{ type: "ephemeral"; ttl?: "5m" | "1h" | undefined; } | undefined

container?:

{ id?: string | undefined; skills?: { type: "anthropic" | "custom"; skillId: string; version?: string | undefined; }[] | undefined; } | undefined

Direct Provider Installation

This provider can also be installed directly as a standalone package, which can be used instead of the Mastra model router string. View the package documentation for more details.

npm install @ai-sdk/anthropic

For detailed provider-specific documentation, see the AI SDK Anthropic provider docs.