OpenAI SDK で Claude を使う：OpenAI 互換エンドポイント、ストリーミング、ツール、制限

pip install openai

import os
from openai import OpenAI

client = OpenAI(base_url="https://aiprimetech.io/v1", api_key=os.environ["AIPRIME_API_KEY"])

resp = client.chat.completions.create(
    model="claude-sonnet-5",
    max_tokens=1024,
    messages=[
        {"role": "system", "content": "You are a concise assistant."},
        {"role": "user", "content": "Explain idempotency keys in two sentences."},
    ],
)
print(resp.choices[0].message.content)
print(resp.usage)

import OpenAI from "openai";

const client = new OpenAI({ baseURL: "https://aiprimetech.io/v1", apiKey: process.env.AIPRIME_API_KEY });

const resp = await client.chat.completions.create({
  model: "claude-sonnet-5",
  max_tokens: 1024,
  messages: [{ role: "user", content: "Write a haiku about retries." }],
});
console.log(resp.choices[0].message.content);

stream = client.chat.completions.create(
    model="claude-sonnet-5",
    max_tokens=2048,
    stream=True,
    stream_options={"include_usage": True},
    messages=[{"role": "user", "content": "Outline a zero-downtime migration."}],
)
for chunk in stream:
    if chunk.choices and chunk.choices[0].delta.content:
        print(chunk.choices[0].delta.content, end="", flush=True)
    if chunk.usage:
        print("\n", chunk.usage)

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="claude-sonnet-5", max_tokens=512, tools=tools,
    messages=[{"role": "user", "content": "What is the weather in Paris?"}],
)
call = resp.choices[0].message.tool_calls[0]
print(call.function.name, call.function.arguments)   # get_weather {"city": "Paris"}

resp = client.chat.completions.create(
    model="claude-opus-5-5", max_tokens=4096, reasoning_effort="high",
    messages=[{"role": "user", "content": "Find the bug in this function: ..."}],
)