## Overview

While ModelStack uses an OpenAI-compatible API format, you can also use the Anthropic SDK by pointing it to ModelStack's API endpoint. This lets you use Anthropic-specific features while routing through ModelStack's unified billing and gateway.

<Note>
  We recommend using the [OpenAI SDK](/sdks/openai-sdk) for the best
  compatibility across all providers. The Anthropic SDK only works with Claude
  models.
</Note>

## Python

### Installation

```bash
pip install anthropic
```

### Setup

```python
import anthropic

client = anthropic.Anthropic(
    api_key="your_api_key",
    base_url="https://api.modelstack.cc"
)
```

### Chat Completion

```python
message = client.messages.create(
    model="claude-sonnet-4-5",
    max_tokens=1024,
    messages=[
        {"role": "user", "content": "Explain quantum computing in simple terms."}
    ]
)

print(message.content[0].text)
```

### Streaming

```python
with client.messages.stream(
    model="claude-sonnet-4-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Write a poem about coding."}]
) as stream:
    for text in stream.text_stream:
        print(text, end="")
```

## TypeScript / Node.js

### Installation

```bash
npm install @anthropic-ai/sdk
```

### Setup

```typescript
import Anthropic from '@anthropic-ai/sdk'

const client = new Anthropic({
  apiKey: 'your_api_key',
  baseURL: 'https://api.modelstack.cc',
})
```

### Chat Completion

```typescript
const message = await client.messages.create({
  model: 'claude-sonnet-4-5',
  max_tokens: 1024,
  messages: [
    { role: 'user', content: 'Explain quantum computing in simple terms.' },
  ],
})

console.log(message.content[0].text)
```

### Streaming

```typescript
const stream = client.messages.stream({
  model: 'claude-sonnet-4-5',
  max_tokens: 1024,
  messages: [{ role: 'user', content: 'Write a poem about coding.' }],
})

stream.on('text', (text) => {
  process.stdout.write(text)
})

await stream.finalMessage()
```

## When to Use the Anthropic SDK

Use the Anthropic SDK when you:

- Need Anthropic-specific features (tool use with Anthropic's format, prompt caching)
- Are only using Claude models
- Have existing Anthropic SDK code and want minimal changes

Use the [OpenAI SDK](/sdks/openai-sdk) when you:

- Want to switch between providers (Claude, GPT, Gemini) without changing SDKs
- Need a single SDK for all models
- Want maximum flexibility