What Agent Skills and SKILL.md do, how they differ from MCP, and how enterprise domain experts can turn practical review know-how into reusable guidance without replacing runtime controls.
MCP does not require a rebuild of stable REST APIs. The architectural choice is how to expose each capability to agents through OpenAPI, vendor hosted MCP, or a shared custom MCP surface.
MCP makes it easier to expose tools to AI agents, but tool connectivity is not execution authority. This article separates agent planning from runtime context, authorization, policy enforcement, approval, idempotency, and deterministic execution in enterprise systems.