I have been building agentic workflows for the better part of a year, and the same friction keeps coming back: my agents have access to too many tools and judgement about almost none of them. MCP fixed the access problem. It standardised how agents call tools, how clients connect, how servers describe themselves. That is real, and it has unlocked a wave of useful servers — browser automation, file systems, search, databases, you name it. But access is not selection. When I ask Claude Code to "build me a real-time chat app with auth," it does not need a list of every MCP server in the world. It needs to know: which database, which realtime transport, which auth provider, and whether those four picks are version-compatible with each other. That is a different problem, and it is the one I built ToolCairn to solve. The shape of the problem If you have built anything serious on top of MCP, you have probably hit one of these: Tool overload. Your agent has 30+ servers connected. Most are noise for the current task.…