They’re not that rare, it’s just that flat big catalogs don’t work well.

The most common failure mode for MCP server design is mapping MCP tools to system APIs. This results in a tool to list files, a tool to rename a file, a tool to copy a file, etc.

You can have 100 “tools”, you just need to define 10-12 areas (actual tools in the MCP model) and actions within each one. It creates a hierarchy that models can dive into when needed and avoid context clutter when that area is not needed.

So instead of 15 tools for file operations you have a single “file” tool, with actions like list, copy, rename, etc.

Single biggest arch requirement for any MCP server (well, any that has more than a handful of operations).