curl --request GET \
  --url https://api.kapso.ai/platform/v1/workflows/{workflow_id}/variables \
  --header 'X-API-Key: <api-key>'

{
  "data": {
    "fixed": {
      "system": {
        "system.flow_id": {
          "type": "string",
          "description": "Flow identifier",
          "always_available": true
        },
        "system.started_at": {
          "type": "datetime",
          "description": "Flow execution start time",
          "always_available": true
        }
      },
      "context": {
        "context.channel": {
          "type": "string",
          "description": "Communication channel (api or whatsapp)",
          "always_available": false
        },
        "context.phone_number": {
          "type": "string",
          "description": "Contact phone number",
          "always_available": false
        }
      }
    },
    "discovered": {
      "system": [],
      "context": [],
      "vars": [
        {
          "path": "vars.user_name",
          "name": "user_name",
          "type": "string",
          "sample_values": [
            "Alice",
            "Bob"
          ],
          "usage_count": 42,
          "last_seen_at": "2025-01-15T10:30:00Z",
          "reference": "{{vars.user_name}}"
        }
      ]
    }
  }
}