In our reference documentation, we state that the CustomPolicyDefinition is only required if you wish to edit the policy in the admin portal. However, upstream documentation has deeper explanation of this functionality and should be included in official documentation.

Upstream Documentation: https://github.com/3scale/3scale-operator/blob/3scale-2.14-stable/doc/adding-custom-policies.md#adding-the-custom-policy-to-a-policy-chain-in-3scale

Official Documentation: https://access.redhat.com/documentation/en-us/red_hat_3scale_api_management/2.14/html-single/installing_red_hat_3scale_api_management/index#injecting-custom-policies-with-the-threescale-operator