In various material at the Cassiopaea site, the word "agents" is sometimes used to designate individuals who either deliberately or unconsciously seek to derail the efforts of another towards spiritual progress or towards fulfillment of a personal mission.
Being an "agent of the Matrix" does not generally involve any direct relationship with any secret service or the like, although such is also not precluded. Neither does it always involve personal ill will. For example, family members with ostensibly the best intentions may be great hindrances for a person's spiritual quest while sincerely believing to be only helpers and protectors (and this becomes especially likely if strategic enclosure is not practiced).
In using the concept, there's the potential trap of falling into exaggeration and self-importance. One should not self-importantly assume that the mere fact of dealing with difficult or tiresome people means that one is at the brink of some great spiritual revelation that "the Matrix" fights tooth and nail to repress. On the other hand it has been seen time and time again that people benefit from distancing themselves from consistently draining or irreparably dysfunctional relationships.
Sometimes the activity of an "agent" is psychic only, without spying or overt conflict or disagreement. Sometimes the activity consists in generating constant worry, as in the case of family members.