I’m not really a fan. But if you’re building a protocol that needs to map to HTTP anyway, then maybe using the HTTP binding everywhere is not totally awful.
In the flip side: I’m currently designing an AI-adjacent protocol, and it will be able to map to WebTransport, but I don’t plan to define non-WebTransport HTTP bindings unless a very compelling reason appears. The main implementations will not use HTTP at all :)
> if you’re building a protocol that needs to map to HTTP anyway
I don't think there is any guarantee that HTTP will always be involved. For example I might be calling a local LLM via CLI/script on a server with a stdio MCP connector that just runs other CLI commands, and never sends any HTTP traffic.
Right. But there is a lot of real-world usage of MCP-over-HTTP-over-the-Internet, and a lot of “harnesses” want to support that use case, so they’re stuck either implementing the HTTP-based protocol or using a shim.
Those are mostly at a different layer. You can speak Thrift or Avro or Protobuf over stdio or HTTP or TCP or carrier pigeon.
gRPC spans layers, and it uses HTTP in a more intrusive way than even MCP does — it expects to own the entire URL space at the IP/port in question. Using gRPC in a nontrivial way for MCP would be fairly heavy-weight: you would probably need to set up reflection and figure out how to bind all the MCP calls to it unless you just use it as a tunnel.
I’m not really a fan. But if you’re building a protocol that needs to map to HTTP anyway, then maybe using the HTTP binding everywhere is not totally awful.
In the flip side: I’m currently designing an AI-adjacent protocol, and it will be able to map to WebTransport, but I don’t plan to define non-WebTransport HTTP bindings unless a very compelling reason appears. The main implementations will not use HTTP at all :)
> if you’re building a protocol that needs to map to HTTP anyway
I don't think there is any guarantee that HTTP will always be involved. For example I might be calling a local LLM via CLI/script on a server with a stdio MCP connector that just runs other CLI commands, and never sends any HTTP traffic.
Right. But there is a lot of real-world usage of MCP-over-HTTP-over-the-Internet, and a lot of “harnesses” want to support that use case, so they’re stuck either implementing the HTTP-based protocol or using a shim.
Would you prefer gRPC, thrift, avro, etc... ?
I would prefer a core transport agnostic protocol, and then see MCP-over-HTTP being a spec on top of that.
Those are mostly at a different layer. You can speak Thrift or Avro or Protobuf over stdio or HTTP or TCP or carrier pigeon.
gRPC spans layers, and it uses HTTP in a more intrusive way than even MCP does — it expects to own the entire URL space at the IP/port in question. Using gRPC in a nontrivial way for MCP would be fairly heavy-weight: you would probably need to set up reflection and figure out how to bind all the MCP calls to it unless you just use it as a tunnel.
grpc mcp is a thing... https://cloud.google.com/blog/products/networking/grpc-as-a-...
Wow, that looks like a huge mess.
Count me as not on board