I've been building Rex and Piper, two AI agents that help with sales prospecting for my higher-ed SaaS business. Here's a simplified version of how I structure Rex's instructions: - Identity: Act as a B2B researcher specializing in higher education. - Task: Research a college and determine whether it's a good prospect for our offering. - Context: Use our ideal customer profile, product information, and qualification criteria. - Constraints: Use verifiable sources, don't make assumptions, and identify missing information. - Output Format: Provide a score, supporting evidence, and a Pursue/Review/Hold/Do Not Pursue recommendation. Each part has a purpose. Identity establishes the expertise, Task defines the job, Context provides the business knowledge, Constraints help prevent bad assumptions, and Output Format makes results consistent. I expected Claude to give me better-qualified prospects rather than generic research, with fewer revisions needed. My biggest takeaway is that I don't necessarily need to repeat all five parts in every prompt. With ICM, much of the Identity, Context, and Constraints can live in reusable files that Claude already knows how to navigate. That's what I'm working toward with my Second Brain: better results, less repeated explanation, and context I can reuse across different AI tools.