AI Plugin IndexSkills vs MCP servers vs plugins: what is the difference?
Skills teach an assistant how to do a task (instructions and files). MCP servers give it new tools that reach outside systems (APIs, databases, apps). Plugins bundle skills, MCP servers and commands into one installable package. Use a skill for know-how, an MCP server for access, and a plugin to install a full setup at once.
| Skill | MCP server | Plugin | |
|---|---|---|---|
| What it is | Folder with SKILL.md | Program exposing tools | Bundle of skills, servers, commands |
| Gives the assistant | Know-how | Access to systems | Both, packaged |
| Runs code | Optional scripts | Yes | Depends on contents |
| Typical example | Write in our brand voice | Query our Postgres database | Full code review setup |
| Works in | Claude apps, Claude Code, API | Most AI assistants | Claude Code, Codex, ChatGPT (each its own format) |
When to use which
Need the assistant to know how to do something your way? Use a skill. Need it to reach a system it cannot see? Use an MCP server. Want a team to get the same setup in one step? Use a plugin.