Design Principles: API vs MCP

As adoption of the Model Context Protocol (MCP) accelerates, many teams are building MCP servers using familiar API design patterns - CRUD-style tools, exposed resources, and thin wrappers over existing APIs. While this approach can function, it does not maximize the value MCP is designed to unlock. MCP is not an API replacement; it introduces a different model built around capabilities, constraints, and agent-driven orchestration. This talk explains why API-oriented designs limit MCP’s effectiveness, even when they “work”. We’ll contrast traditional API principles, where deterministic clients orchestrate workflows with MCP design principles, where autonomous agents reason over narrowly scoped capabilities. Using vendor-neutral examples from deployment and operations workflows, I’ll show how to design MCP tools that are minimal, safe, and agent-native, and clarify when MCP provides more value than an API.