Connecting MCP servers can silently consume tokens before you write a single prompt.
Every connected server preloads its full tool manifest: tool names, descriptions, and the complete JSON schema for every parameter of every tool. That overhead is paid on every message in the session.
Run /insights to see the MCP line in the token breakdown. The fix is to connect only the - servers your current workflow needs and disconnect the rest. I've seen sessions where MCP overhead exceeded the entire conversation history.