Cutting an MCP Server from 85 to 9 Tools: Lessons in Deferred-Tool Search
Goldziher · reddit · 2026-08-08
The author details reducing an MCP (Model Context Protocol) server from 85 tools to 9, arguing that too many thin tools hurt performance:
- Search degradation: Hosts increasingly defer tool schemas and use keyword search. 85 thin tools caused queries to match dozens of options, leading to bad model choices. Consolidating into 9 dense tools with a required mode parameter improved searchability.
- Blast radius: A single defective schema took down the entire tool registry, halting all operations.
Key design decisions include:
- Required mode parameter: Prevents the model from omitting it and silently getting empty results, which are harder to recover from than errors.
- No deprecated aliases: Ghost names compete in keyword search.
- Accepted trade-offs: No outputschema due to spec limits, and coarse annotations (a domain is marked destructive if any mode is).
The CLI and MCP surface are kept in a strict bijection via tests. The project is a local code-intelligence layer written in Rust.
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