Anthropic keeps advertising its MCP (Model Context Protocol), but to the extent it doesn't support other LLMs, e.g. GPT, it couldn't possibly gain adoption. I have yet to see any example of MCP that can be extended to use a random LLM.
You can use it with any LLM in LibreChat, Cody, Zed, etc. See https://modelcontextprotocol.io/clients. The protocol doesn’t prescribe an LLM, has facilities to sample from the client independent of LLM and brings support to build your own bespoke host in their SDK.