alt Hacker NewsIt's instructive to skim the top level of the MCP spec to get a sense. But you can also scroll to the end of the post and see the three .gifs there and see why MCP: because it also defines interaction models with the clients and exposes MCP prompts as `/` (slash) commands and MCP resources as `@` (at) references among other things.
You are right: MCP tools are in essence OpenAPI specs with some niceties like standardized progress reporting. But MCP is more than tools.
Neither slash commands or interaction models are unique to mcp, you can have a http api that offers both.
More concretely, you can have an installable (and updatable) skills that will teach the agents how to use your api and will come with slash commands.
What you cannot do with an mcp is pipe the output into standard tools (jq, head, etc...) or create scripts around it, etc.