vs executable - don’t need a full shell environment to run it
vs openapi - there’s some more advanced agent-specific concepts in MCP, but primarily, I would say, it’s convention and optimizing for the client. Existing openapi specs will often have not great descriptions, or be a huge mess, or just be huge. Making an MCP server requires you to rethink the UX and tools to be optimized for the access patterns of an agent, and also makes you test it with them.
That said, Claude Skills[0] is something more in the vein of cli with —help (really, with a markdown guide), embracing what is already there with a bit of instructions, as opposed to building from scratch.
My personal opinion, having built multiple MCP servers, is that long-term they will not be the primary approach to tools, and that skills for instance are a better approach for most use-cases. But they do have their use-cases.
MCP defines other useful things like Resources, Elicitation, Sampling, prompts which are model/agent-specific, there is nothing in openai or a "good --help" that could match that.
If you don't see this as useful, that is ok, but it is not the same as a command line executable.
