In depth
An MCP registry is the machine-readable counterpart to a marketplace. Where a marketplace is the human UX (browse, rate, click install), a registry is the JSON/HTTP API that tools like the MCPizy CLI query to get server metadata, versions, and install commands.
A typical registry entry includes: server name, description, publisher, current version, install command (stdio command + args, or HTTP URL), required env vars, declared tool list, supported protocol versions, and security/signing metadata. CLIs and marketplaces consume this to render listings and automate installs.
Anthropic maintains a first-party registry at `registry.modelcontextprotocol.io` (as of late 2024 / 2025 rollout). It's the authoritative source for official and verified servers. Community registries (MCPizy, Smithery) federate with it and add curation, ratings, usage analytics.
Registries also support update notifications — when a server publishes a new version, subscribed clients can show an update badge. This is how MCP stays fresh without manual work.