The Model Context Protocol is everywhere right now. Everyone is building MCP servers, connecting tools to agents, and exposing internal systems to AI clients.
What gets less attention is the architecture behind those servers.
An MCP server is not just a template you set up once and forget. Depending on the use case, the right structure can be completely different. A thin wrapper around an API, a local resource server, and an orchestration layer for long-running jobs all expose capabilities through MCP, but they should not be designed the same way.
I have seen six patterns emerge in practice. This is not an academic classification. It is a decision aid:
Which MCP server shape fits the problem?
