{
  "request": {
    "bucket": "my-media-bucket",
    "parentAccessKeyId": "existing-parent-key-id",
    "permission": "object-read-write",
    "prefixes": ["images/", "videos/"],
    "ttlSeconds": 3600
  },
  "response": {
    "result": {
      "accessKeyId": "a1b2c3d4e5f6g7h8i9j0",
      "secretAccessKey": "REDACTED",
      "sessionToken": "REDACTED_SESSION_TOKEN"
    },
    "success": true,
    "errors": [],
    "messages": []
  }
}