>The LLM has no way of knowing which CLI to use and how it should use it…unless each tool is listed with a description somewhere either in AGENTS|CLAUDE.md or a README.md

This is what the skill file is for.

>Centralizing this behind MCP allows each developer to authenticate via OAuth to the MCP server and sensitive API keys and secrets can be controlled behind the server

This doesn't require MCP. Nothing is stopping you from creating a service to proxy requests from a CLI.

The problem with this article is it doesn't recognize that skills is a more general superset compared with MCP. Anything done with MCP could have an equivalent done with a skill.