Example

curl https://api.openai.com/v1/responses/compact \
    -H 'Content-Type: application/json' \
    -H "Authorization: Bearer $OPENAI_API_KEY" \
    -d '{
          "model": "gpt-6-astra",
          "previous_response_id": "resp_123"
        }'

Response

{
  "id": "id",
  "created_at": 0,
  "object": "response.compaction",
  "output": [
    {
      "id": "id",
      "content": [
        {
          "text": "text",
          "type": "input_text",
          "prompt_cache_breakpoint": {
            "mode": "explicit"
          }
        }
      ],
      "role": "unknown",
      "status": "in_progress",
      "type": "message",
      "phase": "commentary"
    }
  ],
  "usage": {
    "input_tokens": 0,
    "input_tokens_details": {
      "cache_write_tokens": 0,
      "cached_tokens": 0
    },
    "output_tokens": 0,
    "output_tokens_details": {
      "reasoning_tokens": 0
    },
    "total_tokens": 0
  }
}