It feels like we are just inventing this adhoc? What does it mean to have [ "type" => "string", "minimum" => 1 ]? For now, I'd be more in favour of just validating these in their own callback rather than abstracting rest_validate_request_arg to handle it until we have a solid spec on how to achieve this.

It feels like we are just inventing this adhoc?

Huh? minimum and maximum are a part of the spec:

• https://github.com/json-schema/json-schema/wiki/Minimum-and-exclusiveminimum
• https://github.com/json-schema/json-schema/wiki/Maximum-and-exclusivemaximum

Although, I'll include a type check for integer and number