# OpenAI Python SDK

> Two changes point the OpenAI Python SDK at TokRouter — base_url and api_key.

```bash
pip install openai
```

```python
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["TOKROUTER_API_KEY"],
    base_url="https://api.tokrouter.dev/v1",
)

# Non-streaming
resp = client.chat.completions.create(
    model="gpt-5.4-mini",
    messages=[{"role": "user", "content": "Explain SSO in one sentence"}],
)
print(resp.choices[0].message.content)

# Streaming
for chunk in client.chat.completions.create(
    model="gpt-5.4-mini",
    messages=[{"role": "user", "content": "Write a four-line poem"}],
    stream=True,
):
    delta = chunk.choices[0].delta.content
    if delta:
        print(delta, end="", flush=True)
```

## Call Claude with the OpenAI SDK

```python
resp = client.chat.completions.create(
    model="claude-opus-5-5",
    messages=[{"role": "user", "content": "Hello"}],
)
```

## Tool calling

```python
tools = [{
    "type": "function",
    "function": {
        "name": "get_weather",
        "description": "Current weather for a city",
        "parameters": {
            "type": "object",
            "properties": {"city": {"type": "string"}},
            "required": ["city"],
        },
    },
}]

resp = client.chat.completions.create(
    model="gpt-5.4",
    messages=[{"role": "user", "content": "What's the weather in Beijing?"}],
    tools=tools,
)
print(resp.choices[0].message.tool_calls)
```

Field-level details: [API reference · Chat Completions](/en/api-reference/chat-completions/).