The Seven Deadly Sins of MCP: Design Sins

This part of the series focuses on the design sins: Gluttony , Pride , and Envy . They belong in this category because they shape the day-to-day quality of the system itself. Things like how much it carries, how clearly its contracts are exposed, and how easy it is for both humans and models to reason about what it can do. Many MCP systems do not fail first as security disasters. They fail because they become expensive, crowded, and hard to reason about. One tool returns far too much data. Another disappears behind a clever abstraction. A third is added because it looks impressive next to the others. None of that feels catastrophic in the moment. It just makes the system slower, noisier, and harder to trust over time. Gluttony, pride, and envy are design sins because all three involve building more than the task requires. Too much data. Too much abstraction. Too many tools, prompts, and resources. They may not create the highest blast radius on day one, but they compound into systems t