Wildfly supports MicroProfile 3.3 (MP) officially. The MP Config specification is part of these [1]. This spec allows to inject config, system and environment properties into CDI-managed classes allowing cloud first development by an overwrite system. 

An example would be shown like this

@Inject
@ConfigProperty(name = "property.key")
String value;

Using JBoss Tools you get a warning about its usage with following error message

No bean is eligible for injection to the injection point [JSR-365 §5.2.2]

Thus JBoss Tools does not detect the usage of @ConfigProperty qualifier.

Possible resolutions would be to

• ignore @ConfigProperty
• support @ConfigProperty with default config source provider evaluating System Environments, System Properties and Config File Properties

1. https://github.com/eclipse/microprofile-config