MCP is incredibly vibe-coded. We know how to make APIs. We know how to make two-way communications. And yet "let's invent new terminology that makes little sense and awkward workarounds on top of unidirectional protocols and call it the best thing since sliced cheese".
MCP is not just providing an API, it’s providing a client that uses that API.
And it does so in a standard way so that my client is available across AI providers. My users can install my client from an ordained URL without getting phished, or the LLM asking them to enter an API key.
What’s the alternative? Providing a sandbox to execute arbitrary code and make API calls? Having an LLM implement OAuth on the fly when it needs to make an API call?
It does just provide an API. Your client may have a way to talk to some software via MCP protocol. You know, like a client can talk to a server exposing an endpoint via an API.
> And it does so in a standard way so that my client is available across AI providers.
As in: it's an API on a port with a schema that a certain subset of software understands.
> What’s the alternative? Providing a sandbox to execute arbitrary code and make API calls?
MCP is a protocol. It couldn't care less what you do with your "tool" calls. Vast majority of clients and servers don't run in any sandbox at all. Because MCP is a protocol, not a docker container.
> Having an LLM implement OAuth on the fly when it needs to make an API call?
Yes, MCP has also a bolted-on authorisation that they didn't even think of when they vibe-coded the protocol. And at least finally there was some adult in the room that said "perhaps you should actually use a standardised way to do this". You know, like all other APIs get OAuth (and other types) of authorisations.
Perhaps confusingly, I’m referring to MCP as the sum of the protocol, a server adhering to the protocol, and clients adding support (e.g. “Connectors”).
The combination of these things turns into an ecosystem.
MCP is a Protocol. The server and the clients are just that. It truly is a rebranding of “API” seemingly just because it’s for a specific purpose. Not that there’s anything wrong with that… call it whatever. But I don’t understand the need to sell it as something else entirely. It is quite literally a reinvention of RPC.
What is indeterministic about MCP servers? Most of them follow fairly simple rules, eg an MCP server to interact with Slack gives pretty deterministic responses to requests.
Or are you confusing the LLM / MCP client invoking the tools being non-deterministic?
MCP is already deterministic. What's huge about it is that it has automatic API discovery and integration built-in. It's a bit rough yet but I think we will only see how it's getting improved more and more.
You really want to use WSDL? OpenAPI v3 would be a much better fit. But it has a tone of features that are completely unnecessary for this use-case. What if we just stripped it down to input and output json schemas? Oh wait ... we just invented MCP.
