See which protocol revision your server actually negotiates, and whether a client expecting 2024-11-05 will work with it.
Once the transport is right, the remaining problem is that nobody can see what your server does. MCP Showcase turns the same URL into a live playground with documentation for every tool.
Any deployed MCP endpoint.
The initialize exchange reports the revision your server settles on, which is not always the one you built against.
Along with the transport, capabilities and full tool list.
MCP revisions are dated rather than numbered, and client and server negotiate a shared one during the initialize handshake. That means the revision that matters is not the one in your dependency manifest — it is the one the two ends agree on at runtime, which this check reports.
Servers built against a newer SDK than they were tested with, or pinned to an old one by a transitive dependency, routinely negotiate something other than what their author expects.
Rarely the core: tools, resources and prompts have been stable throughout. The differences that bite are in capability negotiation, authorization and — most of all — transports. The move to streamable HTTP accompanied the newer revisions, and a transport mismatch causes far more real-world failures than a revision mismatch does. If a client cannot see your server, check the transport before the revision.
Whatever your SDK currently supports, kept reasonably current. Chasing revisions ahead of your SDK gains nothing. Sitting several behind is how a server gradually stops working with newer clients, and because negotiation degrades quietly rather than failing loudly, it is usually noticed as "some people say it does not work" rather than as an outage.
Once a client can reach your server, the remaining problem is that nobody can tell what it does. A tool list is not a demonstration, and a prospect will not install a client to find out. MCP Showcase points at the same URL and produces a live playground with generated documentation for every tool, so evaluating your server takes a click.