A Business Solutions Architect is reviewing a customer service agent built in Copilot Studio that uses generative orchestration. During peak hours, the agent invokes six knowledge sources and four connector tools for nearly every user turn, resulting in slow responses and inflated token consumption. The architect wants to apply the Power Platform Well-Architected Framework to systematically address this. Which pillar's guidance should the architect primarily use to diagnose and remediate the response-time and resource-consumption problems?