Short answer: A registry is a cloud-centered discovery layer; a local-first workflow keeps the contract in your repo and generates the server on save. The first is about finding and connecting to services; the second is about owning the source of truth and never depending on a snapshot. For your own API, local-first is the durable default.

What a registry centers on

The catalog, the connection, and the hosted gateway. It is a discovery and access product, and it assumes the server is something you connect to rather than something you maintain.

What local-first centers on

PropertyRegistryLocal-first
Source of truthPublished entriesSpec in your repo
On changeRe-publishRegenerate on save
OfflineCloud-orientedWorks fully local
AccountOften requiredNot required

Why the source matters for your own API

When the contract is in the repo, the server is a build output, like generated code. It is current, reviewable, and versioned with the API. A registry entry is a copy that has to be kept in sync by hand.

The honest takeaway

Use a registry to find and connect to the world, and keep a local-first generator for the API you build. The boundary is the same as the one between a dependency and your own code.

Return to the Powerduck vs Smithery comparison, or read the MCP server guide.