The new MCP specs from July 2026 removed sessions, the handshake and Mcp-Session-Id are gone. The question you may be asking after looking at that is: is it just REST...with extra steps?

In this talk I will try to answer with data, exposing the same backend in a Kubernetes cluster as a stateless MCP server and as a REST API backend, giving both to the same agent with the same tasks. We can then measure what changes for the agent, like the success rate and the tokens spent, and how each asks the user for missing input or instructions. Then we can see what changes for the humans, the platform team, and where REST still wins (spoiler: HTTP caching).

You will leave with a better understanding of when to use stateless MCP when you need your agent to discover (and self-correct against) tools, and when to use REST when your caller is code and you want caching and a clear, cache-friendly contract.