POST /v1/messages HTTP/1.1
Host: api.anthropic.com
Content-Type: application/json
x-api-key: YOUR_API_KEY_HERE
anthropic-version: 2023-06-01
Accept: application/json

{"model": "claude-sonnet-4-20250514", "max_tokens": 1024, "messages": [{"role": "user", "content": "Hi there"}]}
