When operation handlers request non-existent capabilities, the error messages aren't particularly helpful. For example:

/"WFLYCTL0158: Operation handler failed: java.lang.IllegalStateException: WFLYCTL0364: Capability 'org.wildfly.data-source.invalid' is unknown."

This is largely because it's the CapabilityRegistry that throws the exceptions, and it doesn't have much context about why the capability is needed to use in a better error message.

Likely solutions are:

1) If CapabilityRegistryImpl has more context than is being used, look into using it.
2) Provide more context to CapabilityRegistry (I don't much like this one; providing parameters to a call only for use in a failure message is smelly to me.)
3) Use a custom exception type when the capability is missing, instead of ISE, and have OperationContextImpl catch that and add contextual information.

I expect 3) is the likely solution.