Silent Token Drain: Why Disabled MCP Tools Still Sabotage AI Output

Claude Code's MCP servers load tool schemas even when explicitly disabled, consuming thousands of unnecessary tokens per session that directly degrade AI output quality. The phenomenon known as context rot means longer context windows actually reduce model performance, making every wasted token a tax on reasoning ability. For developers, token optimization isn't about cost savings—it's about preserving the AI's cognitive context across extended work sessions.