I see this question frequently related to MCP, but I'm guessing these questions come from people who haven't built a lot of products using LLMs?
Even if you're LLM could learn the openai spec, you still have to figure out how to concretely receive a response back. This is necessary for virtually any application build using an LLM and requires support for far, far more use cases than just calling an API.
Consider the following use case:
- You need to include some relevant contextual data from a local RAG system.
- There are local functions that you want the model to be able to call
- The API example you describe
- You need to access data from a database
In all of these cases, if you have experience working with LLMs, you've implemented some ad hoc template solution to pass the context into the model. You might have writing something like "Here is the info relevant to this task {{info}}" or "These are the tools you can use {{tools}}", but in each case you've had to craft a prompting solution specific to one problem.
MCP solves this by making a generic interface to sending a wide range of information to the model to make use of. While the hype can be a bit much, it's a pretty good (minus the lack of foresight around security) and obvious solution to this current problem in AI Engineering.
you still have to figure out how to concretely receive a response back
Isn't that handled by whatever Tool API you're using? There's usually a `function_call_output` or `tool_result` message type. I haven't had a need for a separate protocol just to send responses.
Comments
I see this question frequently related to MCP, but I'm guessing these questions come from people who haven't built a lot of products using LLMs?
Even if you're LLM could learn the openai spec, you still have to figure out how to concretely receive a response back. This is necessary for virtually any application build using an LLM and requires support for far, far more use cases than just calling an API.
Consider the following use case: - You need to include some relevant contextual data from a local RAG system. - There are local functions that you want the model to be able to call - The API example you describe - You need to access data from a database
In all of these cases, if you have experience working with LLMs, you've implemented some ad hoc template solution to pass the context into the model. You might have writing something like "Here is the info relevant to this task {{info}}" or "These are the tools you can use {{tools}}", but in each case you've had to craft a prompting solution specific to one problem.
MCP solves this by making a generic interface to sending a wide range of information to the model to make use of. While the hype can be a bit much, it's a pretty good (minus the lack of foresight around security) and obvious solution to this current problem in AI Engineering.
Isn't that handled by whatever Tool API you're using? There's usually a `function_call_output` or `tool_result` message type. I haven't had a need for a separate protocol just to send responses.
Just ask the model to respond with JSON. Give it a template example response.
You don't need a spec.
For sending prompts to the LLM you will absolutely need to hand-craft custom prompts anyways, as each model responds slightly different.