The way the function is described to the LLM matter. Even when the parameters are the same and the effect is the same the title and description can fundamentally influence how the task is performed.

The other issue is that you cannot think of MCP servers as universal pluggable systems that can fit into every use-case with minimal wrapping. Real world scenarios require pulling a lot of tricks. Caching can be done at higher or lower level depending on the use-case. Communication of different information from the MCP server also is different depending on the use-case (should we replace these long IDs for shorter IDs that are automatically translated to longer ones). Should we automatically tinyurl all the links to reduce hallucination? Which operations can be effectively solved with pure algorithms (compress 2-3 operations into one) because doing this with LLMs is not only error-prone but also not optimal (imagine using LLM to grep for strings in many files one by one using tool calls rather than using grep to search for strings - not the same)

There are so many things to consider. MCP is nice abstraction but it is not a silver bullet.

Speaking from experience with actual customers and real use-case.