I keep running into a design question I can't answer on my own, and it's the kind of thing other people building in this space will have opinions on.

MCPulse currently reports 16 things: calls per tool, which client they came from, first-call success, retries, empty results, bad arguments, tool errors, crashes, latency, result size, sessions, cost per session, tool pairs, schema size, and dead tools.

That's too many for a first screen. Sixteen numbers is a wall, and a dashboard that makes you work out what to care about has done half the job.

So the question: if you maintain an MCP server and could see exactly one number about it, which would it be?