What duties did eunuchs perform under the Yongle emperor?

Under the Yongle emperor, eunuchs were utilized to an unprecedented degree for services outside their traditional palace roles. The emperor relied on them to perform a variety of administrative, military, and diplomatic functions, including:

• Diplomatic Missions: Eunuchs served as foreign envoys, most notably Zheng He, who commanded large-scale naval expeditions to the Indian Ocean to display Chinese power and collect tribute.12
• Project Supervision: They were tasked with overseeing special government projects, such as the requisitioning of construction supplies.1
• Military Oversight: Eunuchs acted as regional overseers of military garrisons.1
• Security and Intelligence: In 1420, the emperor established the Eastern Depot (Dongchang), a special eunuch-led agency charged with identifying and investigating treasonable activities.1

By delegating these responsibilities to eunuchs, the Yongle emperor sought to maintain tight control over his administration, relying on individuals who were directly dependent on his authority rather than the traditional bureaucracy.1