(covers information from several alternate timelines)
A temporal agent was an operative working for a faction in the Temporal Cold War based in the 31st century. Enforcing the Temporal Accord, the agents worked to protect the timeline from temporal incursions, and monitor authorized time travel activities.
Daniels was a temporal agent assigned to monitor the initial mission of the Enterprise NX-01 in 2151, posing as a steward. (ENT: "Cold Front") Daniels would continue to interact with Enterprise's crew, specifically Captain Jonathan Archer, to oppose the plans of the Cabal and other Cold War factions, including Vosk, a Na'kuhl operative. (ENT: "The Expanse", "Carpenter Street", "Storm Front", "Storm Front, Part II")
Daniels carried a suite of 31st century equipment to support his mission, including a historical database, a space-time scanner capable of displaying a Temporal Observatory, and a phase device that allowed the user to pass through solid objects. (ENT: "Cold Front", "Shockwave")