Agent Skills · Learn · The open SKILL.md standard
Concepts

Agent skills vs MCP servers

They're often confused, but they solve different problems. A skill teaches the model how to do something. An MCP server gives the model new capabilities to call. The best setups use both.

Side by side

Agent skill (SKILL.md)MCP server
What it isMarkdown instructions + optional bundled filesA running program exposing tools/data over the Model Context Protocol
What it addsKnowledge, procedure, conventionsNew actions: query a DB, call an API, read a system
Runs code?Only scripts it bundles, when the agent chooses to run themYes — it's a live service the agent calls
InstallDrop a file into the agent's skills/rules directoryConfigure a server command + connection
FormatOpen SKILL.md (agentskills.io)Open MCP spec (modelcontextprotocol.io)

When to reach for which

They're complementary, not competing

The strongest pattern is both together: an MCP server exposes the tools, and a skill teaches the agent how to use those tools well — which tool for which job, the right arguments, the gotchas. A skill can explicitly reference an MCP server's tools in its instructions.

GuildSkills catalogs the skills side of this — 84,000+ cross-agent SKILL.md files. For MCP servers, see the open Model Context Protocol spec.

Frequently asked

Skills vs MCP servers — answered

Is a skill the same as an MCP server?
No. A skill is markdown instructions that teach the model how to do something. An MCP server is a running program that gives the model new tools to call. Skills add knowledge; MCP servers add capabilities.
Can I use a skill and an MCP server together?
Yes — that's the ideal setup. The MCP server exposes the tools; the skill teaches the agent how to use them well. A skill can reference an MCP server's tools directly in its instructions.
Which should I build first?
If the model already can do the task but does it inconsistently, write a skill. If it physically can't reach the data or system it needs, build (or install) an MCP server first, then add a skill to guide its use.