Shrinking MCP Tool Descriptions Makes Agents Smarter: The Hidden Cost of Context Noise
Street_Inevitable_77 · reddit · 2026-08-12
A developer discovered that overly verbose MCP tool and parameter descriptions severely degrade Agent performance. Since these descriptions are sent with the context on every tool call, detailed docs, edge case explanations, and repetitive descriptions intended as 'safety margins' actually become noise the model must filter through constantly.
Optimization & Gains:
- Trimmed all tool descriptions to a single tight sentence, only adding detail where the tool name was ambiguous.
- The result was a win-win: a significant drop in token usage and a noticeable improvement in tool selection reliability, as the model no longer wades through filler to find the one line that matters.
The author notes that providing excessive information isn't always safe; past a certain point, noise incurs a continuous hidden cost and interferes with decision-making.
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