A more thorough explanation:

A diplomatic agent is a representative of a country who is authorized to act on behalf of their government in another country. There are four categories of diplomatic agents: ambassadors, envoys and ministers plenipotentiary, ministers resident accredited to the sovereign, or chargés d'affaires accredited to the minister of foreign affairs.

For example, the United States ambassador to France is a diplomatic agent who represents the U.S. government in France. They have the authority to negotiate treaties, attend official events, and communicate with the French government on behalf of the U.S.

This term is important in international relations and diplomacy, as diplomatic agents play a crucial role in maintaining relationships between countries and promoting their interests.