Because it's about the MCP Host <-> LLM interaction. Not how a vanilla server and client communicate to each other and have done so for the last 5+ decades.
This really is not that hard to understand. The LLM must be "bootstrapped" with tool definitions and it must retain stable enough context to continue to call those tools into the future.
This will fail at some point, with any model. It will pretend to do a tool call, it will simply not do the tool call, or it will attempt to call a tool that does not exist, or any of the above or anything else not listed here. It is a statistical certainty.
I don't know why people are pretending MCP does something to fix this, or that MCP is special in anyway. It won't, and it's not.
This really is not that hard to understand. The LLM must be "bootstrapped" with tool definitions and it must retain stable enough context to continue to call those tools into the future.
This will fail at some point, with any model. It will pretend to do a tool call, it will simply not do the tool call, or it will attempt to call a tool that does not exist, or any of the above or anything else not listed here. It is a statistical certainty.
I don't know why people are pretending MCP does something to fix this, or that MCP is special in anyway. It won't, and it's not.
Make sure you have a good understanding of the overall model: https://hackteam.io/blog/your-llm-does-not-care-about-mcp/
Then take a look at research like this: https://www.archgw.com/blogs/detecting-hallucinations-in-llm...