An agent = a specialized “AI worker” with its own role and job (code reviewer, researcher, debugger, and so on) — curated and ready to use, with clear notes on what each does. copy it to set up as a subagent/role
Prompt · Rule · Agent — how they differ: by “what they change about the AI” and “when they run”
💡 How to use: Copy the agent definition and set it up as a subagent (e.g. .claude/agents/ in Claude Code) or as a Custom GPT / custom mode in the AI you use → then call that specialized agent as the task needs.