This is not at all an MCP server you want to use with a regular tool, as this is about low level context window management. Tbh it’s really trivial to do this, and I have no idea why OP decided to make an MCP server for this as it’s completely useless for that.
As a matter of fact, i think this is not a problem at all as Anthropic makes it extremely easy to cache stuff; you just set your preferred cache level on the last message, and Anthropic will automatically cache it under the hood. Every distinct message is another “cache” point, eg they first compute the hash of all messages, if not found, compute the hash of all messages - 1, etc.
It’s really a non problem.