MCP tools or skills: which should I use

Both give an agent a new capability, and an agent can use both at once. They differ in how much work they are and how much control you get.

	MCP tool	Skill
Setting it up	Easy: one click in the Marketplace, or paste JSON	You write the code
Control	Whatever the upstream tool exposes, no more	Exactly what you decide
Upkeep	Little	Ongoing, as schemas and APIs change

Reach for an MCP tool when

The thing you want already exists. Linear, Notion, GitHub, Stripe, Salesforce and hundreds more are in the MCP Marketplace behind an OAuth flow, so there is nothing to write and nothing to maintain. This is the right default.

Reach for a skill when

You need something an off-the-shelf tool will not do: a multi-step workflow, your own business rules, or a narrower surface than the upstream API exposes. A skill is a reusable capability package, either from the Marketplace or written by you, and you own its behaviour.

A useful middle path

Attach the MCP tool first and see how far it gets you. If the agent keeps making the same mistake with it, that is the point at which a skill wrapping the tool in your own rules starts paying for itself.