Claude Code Subagents vs MCP Servers: What's the Difference?
Subagents and MCP servers are the two most powerful ways to extend Claude Code, and they're often confused. The short version: a subagent changes who does the work; an MCP server changes what they can reach.
A subagent is a specialist with its own instructions and context. An MCP server is a connection to an outside system — a database, a browser, an issue tracker. Used together, they let Claude Code do real work across your whole stack.
Quick verdict
Add a subagent when you want a specialist to handle a kind of task. Add an MCP server when Claude Code needs to read from or act on a system it can't reach today. Most strong setups use both.
Use a subagent when…
- You want a specialist role, like reviewer or SEO auditor
- The task is long and should stay out of your main context
- You want to limit which tools the task can use
- You want consistent output for a repeated job
Use an MCP server when…
- Claude Code needs data from another system
- You want it to act in a tool: a browser, database or tracker
- You want the same connection across many tasks
- A ready-made server already exists for your tool
Side-by-side comparison
| Subagents | MCP servers | |
|---|---|---|
| What it is | A specialist with its own system prompt | A connection that gives Claude Code new tools and data |
| Defined in | Markdown files in .claude/agents/ | Claude Code's MCP configuration |
| Adds | Expertise and focus | Capabilities and access |
| Context | Runs in its own context window | Its tools are available in whichever context uses them |
| Examples | Code reviewer, test writer, SEO auditor | Database, browser automation, issue tracker, docs search |
What a subagent is
A subagent is a markdown file with a name, a description of when to use it, optional tool limits and a system prompt. When Claude Code hands it a task, it works in a fresh context window and reports back. That keeps big jobs — reviewing a pull request, auditing every page — from crowding your main conversation.
What an MCP server is
MCP, the Model Context Protocol, is an open standard for connecting AI tools to outside systems. An MCP server exposes tools and data — run a database query, open a web page, create an issue — that Claude Code can then call. Many servers are available off the shelf, and you can write your own.
How they work together
The best setups pair them. A database-migration subagent becomes far more useful with a database MCP server; an SEO-audit subagent can check live pages through a browser server. You can also restrict a subagent's tools so it only touches the MCP servers its job needs.
- Subagent: technical SEO auditor + MCP: browser → audit live pages
- Subagent: bug triager + MCP: issue tracker → label and summarise issues
- Subagent: data analyst + MCP: database → answer questions with real queries
Where claudeagents fits
claudeagents gives you the subagent side ready-made: 120+ specialists for coding, SEO and marketing, plus 54 skills and 54 slash commands. Add the MCP servers for the tools you already use, and the agents can put them to work.
Frequently asked questions
Is an MCP server the same as a subagent?
No. A subagent is a specialist that does a type of work. An MCP server is a connection that gives Claude Code access to an outside system.
Can a subagent use MCP tools?
Yes. Subagents can use MCP tools, and you can limit each subagent to only the tools it needs.
Do I need MCP servers to use subagents?
No. Subagents work with Claude Code's built-in tools for files and commands. MCP servers are only needed when an agent must reach another system.
Who makes MCP?
Anthropic introduced the Model Context Protocol as an open standard, and many other tools now support it.
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