Claude Sonnet 5

The previous Sonnet flagship.

Knowledge cutoff Jan 2026. Legacy model: Sonnet 5.5 is the current Sonnet release. Default effort is high.

Make your first request

{
  "model": "claude-sonnet-5",
  "messages": [
    {
      "role": "user",
      "content": "Hello, world."
    }
  ]
}