Claude TypeScript SDK

Quick Start

npm install @anthropic-ai/sdk
export ANTHROPIC_API_KEY='your-key'

import Anthropic from '@anthropic-ai/sdk';

const client = new Anthropic();
const message = await client.messages.create({
  model: 'claude-opus-4-5-20251101',
  max_tokens: 1024,
  messages: [{ role: 'user', content: 'Hello!' }],
});

Core Patterns

Basic Message

const message = await client.messages.create({
  model: 'claude-opus-4-5-20251101',
  max_tokens: 1024,
  messages: [{ role: 'user', content: 'Your prompt' }],
});
console.log(message.content[0].type === 'text' && message.content[0].text);

Streaming

const stream = client.messages.stream({
  model: 'claude-opus-4-5-20251101',
  max_tokens: 1024,
  messages: [{ role: 'user', content: 'Write a poem' }],
});
stream.on('text', (text) => process.stdout.write(text));
const final = await stream.finalMessage();

Tool Use

const tools: Anthropic.Tool[] = [{
  name: 'get_weather',
  description: 'Get weather for a location',
  input_schema: {
    type: 'object',
    properties: {
      location: { type: 'string', description: 'City name' },
    },
    required: ['location'],
  },
}];

const response = await client.messages.create({
  model: 'claude-opus-4-5-20251101',
  max_tokens: 1024,
  tools,
  messages: [{ role: 'user', content: 'Weather in NYC?' }],
});

For detailed examples, see REFERENCE.md.

Available Models

• claude-opus-4-5-20251101 - Most capable
• claude-sonnet-4-5-20250929 - Balanced
• claude-haiku-4-5-20251001 - Fastest

Error Handling

try {
  const message = await client.messages.create({...});
} catch (error) {
  if (error instanceof Anthropic.APIError) {
    console.error(`Status: ${error.status}, Message: ${error.message}`);
  }
}

Resources

• TypeScript SDK GitHub
• API Documentation
• Agent SDK Demos