Evidence-first authority page
How to Fix Token Bloat & Context Window Overflow in MCP
Why connecting many MCP servers can overflow a model's context window, and practical ways to reduce token overhead.
Direct answer
MCP token bloat happens because every connected server's tool descriptions and schemas are loaded into the model's context on every request — connecting many servers with verbose tool descriptions can consume a large fraction of the available context window before the actual task even begins. Reduce it by connecting only the servers a given task needs and trimming overly verbose tool descriptions.
Last reviewed 2026-08-29
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Why this happens
Each MCP server declares its available tools with a name, description, and input schema, and this full declaration is included in the model's context so it knows what it can call — with enough servers connected simultaneously, this overhead alone can consume a meaningful share of the context window before any actual conversation or task content is added.
Practical mitigations
- Disconnect or disable servers not relevant to the current task rather than leaving every server connected by default.
- If you're authoring a server, write concise, specific tool descriptions — verbose descriptions written for a human reader consume more tokens than necessary without improving the model's ability to use the tool correctly.
- Where a client supports it, group related tools under fewer, more general tool definitions rather than many narrow ones, reducing the total schema overhead.