I added MCP servers to Claude Code. Here's what they cost in tokens.

Integrating MCP servers into Claude Code extends its capabilities, but introduces significant token costs. Each registered MCP tool injects a tool-definition block into the context window during every turn. This process is not a one-time expense; instead, it compounds throughout the entire session. By analyzing the server's tool manifest, the system prompt includes specific details like tool name, description, and inputSchema, which directly increases the total number of tokens used per interaction.