Schema should have a type defined, being explicit about type of data a schema describes and can be used to validate, helping standardize the type of data being made available
OpenAPI Schema Type Info
Message: Schema Has Type Property
Policies
Schema Type
Every schema needs a type. Without it, validation tools and code generators can not do their job, and consumers have no way to know what shape of data to expect.
Data Validation
Data validation at the API boundary catches problems before they propagate. Type checking, format enforcement, required fields, and enum validation are the building blocks of data integrity.