Claude Skills vs MCP servers: when to use which.

Q: What’s the actual difference?

A Claude Skill is a markdown file that Claude reads when triggered. The skill describes a procedure, prompt template, or workflow — Claude follows it as instructions [cite: https://docs.anthropic.com/en/docs/claude-code/skills · 2026-04-15 · high].

An MCP server is a long-running process that exposes typed tools to Claude over stdio [cite: https://modelcontextprotocol.io · 2024-11-25 · high]. Claude calls the tools by name, gets typed responses, and acts.

Skills are instruction-time extension. MCP is execution-time extension.

Q: When does a Skill make sense?

Skills shine when the work is “Claude itself doing the work, but smarter.” Examples:

• A prompt template for code review with your team’s specific style preferences
• A multi-step workflow where Claude follows a checklist
• Domain knowledge Claude should reference for a class of tasks
• A persona / voice guide for content generation

The Skill is text. Claude reads it, internalises it, behaves accordingly. No external process. No state across sessions [cite: https://reddit.com/r/ClaudeAI/comments/1sxj6s3/ · 2026-04-20 · medium].

Q: When does MCP make sense?

MCP shines when Claude needs to do something Claude itself can’t do:

• Read or write files on the user’s machine
• Hit a database or API with credentials
• Run a deterministic algorithm that Claude shouldn’t try to mentally execute
• Query stateful systems (calendars, ticket queues, build systems)

The MCP server is code. It runs as a subprocess. Claude calls its tools and gets structured responses [cite: https://en.wikipedia.org/wiki/Model_Context_Protocol · 2026-04-10 · medium].

Q: Decision tree?

Does Claude need to execute a deterministic operation against
external state (files, APIs, databases, processes)?

├── Yes → MCP server
└── No  → Does the user want shareable, version-controlled
         instructions Claude can follow?
         ├── Yes → Skill
         └── No  → Just a system prompt is fine

Q: Can I combine them?

Yes, and increasingly people do. A Skill can instruct Claude to use specific MCP tools in a specific order. The Skill is the workflow; MCP servers are the verbs.

Example: a Skill for “morning email triage” instructs Claude to call the gmail-mcp server’s list-unread tool, classify each message using a specific prompt, then call gmail-label to apply labels. Skill = workflow. MCP = mechanism.

Q: What’s the maintenance cost difference?

Skills: zero process, zero ports, zero secrets. They live as markdown files in the user’s Skills folder. Sharing means sharing a file [cite: https://reddit.com/r/ClaudeAI/comments/1sxj6s3/ · 2026-04-20 · medium].

MCP servers: a Node or Python process. Needs install, needs config, may need API keys, needs restarts when config changes. More powerful, more friction.

Q: What about Claude Code specifically?

Both apply. Claude Code supports Skills and MCP servers, with Skills surfacing as triggerable instructions and MCP servers exposing tools. The distinction is the same: Skills shape Claude’s behaviour, MCP gives it new abilities.

Q: Real-world examples worth installing?

Useful Skills (markdown, free):

• A “git commit message” Skill that enforces conventional-commits
• A “code review” Skill with your team’s checklist
• A “summarise this thread” Skill for long Slack channels

Useful MCP servers (process, free / open-source):

• filesystem-mcp — read/write files in your project
• github-mcp — operate on issues, PRs, repos
• cv-mirror-mcp — lint a CV against 5 ATS parsers

Q: Where does this go from here?

The clean line is: Skills define how Claude should think; MCP servers define what Claude can do. Most workflows benefit from both. Reddit threads have started accumulating real-world combinations: r/ClaudeAI: “best Skill + MCP combos for daily work” is the canonical thread to date.

Sources

• Claude Skills documentation
• Model Context Protocol official spec
• Wikipedia: Model Context Protocol
• r/ClaudeAI thread on Skill + MCP combinations
• Awesome MCP Servers list