Anthropic announced the Model Context Protocol in November 2024. A year and a half later it is the closest thing the agent ecosystem has to a standard, with Anthropic's reference servers, a long tail of community implementations, IDE-level integrations in Cursor and Zed, and a W3C-adopted browser-side variant called WebMCP. The protocol is no longer the question. The question is what to build on top of it.
David Soria Parra, the MCP co-creator at Anthropic, recently gave a talk on the design lessons of the protocol's first year — the things teams keep doing wrong, and the design discipline the second year is going to require. The talk is the kind of artifact you don't normally get from a protocol author at this stage of an ecosystem's life: a clear, opinionated summary of where the mistakes are concentrated and what the corrective shape looks like.
This piece is my summary of those lessons, with the design rationale I think a developer building an MCP server in May 2026 actually needs. There are six of them.
1. Don't wrap REST as MCP
This is the design mistake every team makes once.
