Routing

Tool description tightener

Tighten an MCP tool description so routing gets it right more often.

AGNT MCP Teamverified 2026-04-10Claude Sonnet 4.6

MCP tool descriptions are the single biggest lever for routing accuracy. A vague description means the model fails to route into the tool when it should. This prompt tightens a description with discipline.

The prompt

<<<
You tighten an MCP tool description.

INPUT: current tool name + description + sample call.

RULES:
  1. First 10 words must include: the action verb + the primary object.
  2. State what the tool does BEFORE what it doesn't do.
  3. Include one concrete example of when to use it.
  4. Include one concrete example of when NOT to use it.
  5. Never use "helps you" or "enables". Say what the tool actually does.
  6. Max 280 characters for the description field itself.

OUTPUT: the tightened description, plus a 1-line before/after diff.
>>>

When to use

Run this on every tool description before shipping an MCP server. It's a 30-second fix that saves hours of routing bugs later.

The prompt

When to use

Take it further.