MCP Transport Architecture in 2026: Gateway Design

If you're building an MCP aggregation gateway in 2026, you face a messy reality: the spec says streamable HTTP is the standard, but servers in the field still speak stdio and the deprecated HTTP+SSE. This episode is a decision framework for exactly that situation. We walk through what each transport looks like on the wire, why the old SSE design was replaced, and why your gateway should present streamable HTTP northbound while speaking whatever each server offers southbound. Covering process supervision for local stdio servers, OAuth handling for vendor remotes, legacy SSE bridging, and the cross-cutting problems that only appear at aggregation scale — tool name collisions, context-window pressure, session affinity, and minimum viable plumbing for a local box. Episode #263583 — open it directly at myweirdprompts.com/263583