Custom instructions #196

Would you consider allowing users to customise the instructions field as described at https://modelcontextprotocol.info/blog/server-instructions/?

Currently the server returns Altinity ClickHouse MCP Server - A Model Context Protocol server for interacting with ClickHouse databases as its instructions. We have a server with some custom tools configured, so I was looking for a way to provide precise information about which tools suit certain purposes, and more detailed usage information for the server.