Skills vs MCP vs subagents vs CLAUDE.md
Agent skills, MCP servers, subagents and CLAUDE.md files compared: what each does, when to use it and how they work together.
Updated Nov 10, 2026 · 4 min read
These four ideas are often confused because they all "extend" an agent. They solve different problems.
- Skills teach how: procedures, checklists, templates and scripts, loaded only when relevant.
- MCP servers give access: tools and data from other systems (GitHub, databases, Figma).
- Subagents split work: separate agents with their own context for parallel or isolated tasks.
- CLAUDE.md / AGENTS.md set house rules: always-on project context and conventions.
A simple rule
If the agent cannot reach something, add MCP. If it can reach it but does the job badly, add a skill. If the rule applies to every single task in a project, put it in CLAUDE.md or AGENTS.md. If a task is big enough to deserve its own context window, use a subagent.
How they combine
A strong setup for shipping a feature might use a GitHub MCP server for access, a planning skill and a code review skill for method, a testing subagent for verification and an AGENTS.md for repo conventions.
FAQ
Are skills replacing MCP?
No. Skills and MCP are complementary. Many skills are written specifically to use an MCP server well.
Is a CLAUDE.md file a skill?
No. CLAUDE.md is always loaded. Skills load on demand. Some popular repos, like the Karpathy guidelines, ship both forms.
Next guide
Do agent skills actually work? What the research says