Three Prompts—Role, Decision-Making, Output—Take Center Stage in Building Claude Agents

When building an agent with Claude (Anthropic's AI), a prompt-design approach centered on defining three elements—Role, Decision-making, and Output quality—is being formalized as a practical method within the developer community. The discussion that sparked the topic put forward a role-definition prompt template such as "You are an expert [role] whose primary goal is to [objective]. Stay within this scope and ask clarifying questions when information is missing.", which states in a single sentence the agent's expert stance and objective, its scope, and how it should act when information is missing. As usage shifts from general chat to agents that use tools and handle long-running tasks, the clarity of the system prompt is positioned as key to curbing an agent's runaway behavior and vague output.