It was just a few months ago that the MCP spec added a concept called "prompts" which are really similar to skills.

And of course Claude Code has custom slash commands which are also very similar.

Getting a lot of whiplash from all these specifications that are hastily put together and then quickly forgotten.

My understanding is, that MCP Prompts and Slash Commands are "user triggered" whereas Skills (and MCP Tools) are "model triggered".

Other than that it appears MCP prompts end up as slash commands provided by an MCP Server (instead of client side command definitions).

But the actual knowledge that is encoded in skills/commands/mcp prompts is very similar.

It's a "standard" though! /s