Looking at https://github.com/modelcontextprotocol/python-sdk?tab=readm... it's clear that there must be a decision connecting, for example, `tools` returned by the MCP server and `call_tool` executed by the host.

In case of Claude Desktop App, I assume the decision which MCP-server's tool to use based on the end-user's query is done by Claude LLM using something like ReAct loop. Are the prompts and LLM-generated tokens involved inside "Protocol Handshake"-phase available for review?