Claude skills vs MCP: what's the difference?

What does a Claude skill do?

A skill carries method. It is a file of instructions that the model loads when a particular kind of work shows up, and it encodes the discipline of doing that work well: the checklist, the order of steps, the judgment calls, the traps that separate a sharp audit or a piece of copy that converts from a generic one anybody could produce.

The detail people miss is that a skill changes behaviour without touching what the model can reach. Loaded or not, the model still has the same files, the same accounts, the same world in front of it. The skill only changes the quality and the shape of how it works through that world. Think of it as the difference between a competent generalist and a specialist who has done the job a thousand times: same hands, same tools on the bench, but a method that produces a reliably better result. A skill is that method, written down and reusable.

What does an MCP do?

An MCP is the bridge to the outside world. It is the connection that lets the model reach a real system instead of working from memory: a live Search Console account, an ad platform, a database, a file store. Without it, the model can reason about SEO beautifully and still have no actual numbers to reason about. With it, the model can pull the real search-terms report and act on what is genuinely there.

The thing to hold onto is that an MCP grants access, not competence. It opens the door to the data; it has no opinion about what to do once inside. Connecting a model to an ad account does not make it a good media buyer any more than handing someone the keys to a workshop makes them a carpenter. The MCP supplies the live material. Whether that material gets handled well is a separate question entirely, and that question is the skill’s department.

How are skills and MCP different?

The cleanest framing is two words: knowledge versus connection. A skill is knowledge loaded as a file, telling the model how to approach a task. An MCP is connection to a running service, giving the model something real to act on. One shapes the how; the other supplies the what.

People conflate them because both feel like “adding a capability to Claude,” and in a loose sense both do. But the line underneath is sharp and worth keeping straight, because confusing it leads to the wrong fix. If the model produces a shallow, generic audit, that is a method gap and you reach for a better skill; adding another data connection will not help. If the model is reasoning in a vacuum with no real numbers, that is an access gap and you reach for an MCP; a better checklist will not conjure data that was never connected. Knowing which gap you actually have is the whole value of keeping the two ideas apart.

When do you use each, or both?

Most serious work wants both at once, and the canonical pairing makes the point. An SEO audit skill running against a Search Console MCP is method and live data meeting inside the same task: the skill knows what a thorough audit looks like and in what order to check things, while the MCP supplies the actual impressions, positions, and queries to check. Run either alone and you get half a job. The skill alone produces a tidy, confident audit of data it never saw. The MCP alone produces a pile of real numbers and no disciplined read on them.

The practical rule is to diagnose before you add. When the output is well-structured but built on nothing real, you have access without method backwards, and the missing piece is the connection. When the output is grounded in real data but sloppy and generic in how it handles it, the missing piece is the skill. The strongest setups stop treating these as a menu to pick from and start treating them as a pair: a method that knows how, pointed at a connection that reaches what.

For a deeper grounding in the method side of this pairing, start with what Claude skills actually are. For the connection side, see what an MCP actually is.