The primary command for managing individual agents: creating them from the catalog, listing, starting and stopping, inspecting budget utilization, viewing logs, and rolling back configuration to a previous revision. Agents run as Claude Code sessions inside tmux, and this command drives their lifecycle.
A new agent must be created first (fleet agent create or fleet template spawn) before fleet agent start <name> can launch it. Starting an agent is license-gated; read-only operations like list and budget are not.