A bean manager is only available in modules in which CDI has been enabled.
Where EE modules are defined to be; ejb-jar, rar, client jar and war.
This is a missmatch between the EE spec and the CDI spec. According to the CDI spec, any archive with a beans.xml is defined as a BeanArchive and should be included in a BeanManager, EE define it to be only EE modules should trigger BeanManager creation.
Opening this up to follow the CDI spec will let any library use the BeanManager to introspect other BeanArchives without having to involve the owning EE module in the loop.