Skills DirectoryClaude Skills vs MCP Servers
Claude Skills and MCP servers are often mentioned together, but they solve different problems.
The simplest distinction:
- Skills teach the agent a workflow.
- MCP servers give the agent tools or data.
A skill is process. MCP is capability.
What a skill does
A Claude Skill packages instructions, examples, and sometimes helper files. It tells Claude how to approach a task.
Examples:
- how to review code
- how to write a PRD
- how to debug systematically
- how to draft a newsletter
- how to audit UI accessibility
A skill answers:
What steps should the agent follow?
What an MCP server does
An MCP server exposes tools, resources, or prompts over the Model Context Protocol. It lets an AI client call external systems in a structured way.
Examples:
- query a database
- search Linear issues
- read GitHub pull requests
- fetch analytics
- call a SaaS API
- browse files or docs
An MCP server answers:
What external capability can the agent use?
Side-by-side comparison
| Question | Claude Skill | MCP Server |
|---|---|---|
| Primary job | Teach workflow | Expose tools/data |
| Typical form | SKILL.md folder | Running local/remote server |
| Best for | Process, standards, decision trees | APIs, databases, files, SaaS tools |
| Risk surface | Instructions, scripts, hidden behavior | Tool permissions, auth, data access |
| Example | Code review checklist | GitHub issue API connector |
When to use a skill
Use a skill when the agent needs a repeatable process:
- Review every PR the same way.
- Write release notes in a consistent format.
- Follow a debugging loop.
- Apply design-system rules.
- Create content briefs from a fixed template.
Skills are especially useful when the task requires judgment and sequence.
When to use MCP
Use MCP when the agent needs access to external systems:
- fetch customer records
- inspect project management tickets
- query an internal database
- call a search API
- manipulate files through a controlled server
- authenticate against a SaaS tool
MCP is especially useful when the task requires live data or tool calls.
Use both for real workflows
The strongest setups combine them.
Example: GitHub triage
- MCP server: exposes GitHub issues and pull requests.
- Skill: defines the triage policy, labels, escalation rules, and summary format.
Example: SEO workflow
- MCP/API/tool: gets Search Console or keyword data.
- Skill: turns that data into a prioritization process and content brief.
Example: database migration
- MCP server: exposes database metadata.
- Skill: defines migration planning, risk checks, rollback plan, and approval gates.
Security differences
Both can be risky, but the risks differ.
Skill risks:
- malicious instructions
- prompt injection
- unsafe shell commands
- credential exfiltration instructions
- hidden helper files
MCP risks:
- over-broad permissions
- exposed tokens
- destructive tools
- data leakage
- weak auth or logging
For both, prefer least privilege and human approval for destructive actions.
Practical rule
Ask:
Does the agent need to know how to do something, or does it need access to something?
If it needs to know how: use a skill.
If it needs access: use MCP.
If it needs both: combine them deliberately.