MCP lesson learned: collapse CRUD endpoints into fewer tools with enum params, not 20 granular ones

Relevant-Potential17 · reddit · 2026-09-19

After months of building MCP servers, the author's key lesson: don't mirror your REST API by exposing every CRUD endpoint as a separate tool.

Past 15–20 granular tools, schemas clutter the system prompt, the model gets indecisive, hallucinates tool calls or picks the wrong one, and latency rises;
Better: collapse into broader actions with enum params, e.g. manageuser(action="search"|"update", ...) or queryuser(filterby="id"|"email", value);
Treat tool description fields as prompt engineering, not swagger docs — explicitly telling the model when NOT to call a tool cut bad invocations in half.

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