Currently, toolbox validates swagger spec content at the following levels:

• yam/json syntax
• swagger schema

There are semantic validations not done to check, for instance, duplicated operationId.
Semantic validations should be implemented to reject invalid swagger docs. Source for semantic validations: https://github.com/swagger-api/swagger-editor/tree/master/src/plugins/validate-semantic

More info at https://github.com/3scale/3scale_toolbox/issues/223