Because it's not a request format for LLMs, it's a request format for client software that is instrumenting LLMs. If you make a connector to say HomeAssistant to turn on/off your lights you're exposing a tool definition which is really just a JSON schema. The agent will present that tool to the LLM as one it's allowed to use, validate that the LLM matched your change_light_state tool schema and send off the appropriate API call to your server.
The spec is genuinely a hot fucking mess that looks like a hobby project by an overeager junior dev but conceptually it's just a set of JSON schemas to represent common LLM things (prompts, tools, files) and some verbs.
The spec is genuinely a hot fucking mess that looks like a hobby project by an overeager junior dev but conceptually it's just a set of JSON schemas to represent common LLM things (prompts, tools, files) and some verbs.
The useful content of the spec is literally just https://github.com/modelcontextprotocol/specification/blob/m... and even then it's a bit much.