| key | (optional) string | The variable name as used when rendering context in templates. | [default to undefined] |
| type | (optional) string | The data type for this variable. Use JSON Schema-like names for values (string, boolean, number, object, array) or "function" for template utility/helper functions (e.g. __dateTool.format(), __esc.html()). | [default to undefined] |
| description | (optional) string | Human-readable description explaining what this variable represents. | [default to undefined] |
| example | (optional) any | Example value demonstrating the format and usage. For type "function", often a Velocity-style call (e.g. $__esc.html($value)). Can be a string, number, boolean, object, array, or null when no example is defined. | [default to undefined] |