{
  "name": "my_entity",
  "description": "Description of what this entity represents",
  "fields": {
    "field1": {
      "type": "string",
      "optional": false,
      "normalize": ["trim", "lower"],
      "description": "First field - normalized to lowercase"
    },
    "field2": {
      "type": "string",
      "optional": true,
      "normalize": ["trim"],
      "description": "Optional second field"
    },
    "field3": {
      "type": "string",
      "optional": false,
      "normalize": ["trim", "replace:_:-"],
      "description": "Field with underscore to hyphen replacement"
    }
  },
  "primary_key": ["field1", "field2"],
  "constraints": [
    {
      "field": "field1",
      "regex": "^[a-z0-9][a-z0-9._-]{0,127}$",
      "description": "Must start with alphanumeric, can contain dots, underscores, hyphens"
    },
    {
      "field": "field2",
      "regex": "^[a-z0-9][a-z0-9._-]{0,127}$",
      "when_present": true,
      "description": "Same pattern but only validated when present"
    }
  ]
}