--- a/base/rendered.txt
+++ b/head/rendered.txt
@@ -248,6 +248,8 @@
 application/a2a-agent-card+json — an A2A Agent Card
 
 application/mcp-server-card+json — an MCP Server Card
+
+application/mcp-server+json — an MCP Registry server.json document
 
 application/agent-skills+json — Agent Skill Metadata json file
 
@@ -1924,7 +1926,8 @@
 A Server Card is a static discovery document for a single HTTP-based MCP
 server (its identity and connection details). It is distinct from the MCP
 Registry's server.json, an installable-package descriptor — a separate
-artifact type that this appendix does not address.
+artifact type mapped in
+Mapping to MCP Registry server.json.
 
 Overview
 
@@ -2141,6 +2144,210 @@
 
 Composability: MCP servers can be packaged with related
 artifacts (A2A agents, datasets) in nested catalogs.
+
+Mapping to MCP Registry server.json
+
+This appendix describes how the MCP Registry server.json format
+(see modelcontextprotocol/registry)
+maps to AI Catalog as a first-class cataloged artifact type, enabling
+installable MCP servers to be discovered alongside other AI artifacts
+through a unified catalog.
+
+Two MCP server artifacts, two types. The MCP ecosystem defines two
+distinct documents for a server, and AI Catalog gives each its own known
+type:
+
+MCP Server Card (application/mcp-server-card+json) — a static
+discovery document for a connectable HTTP server (identity, transport,
+capabilities, auth). See Mapping to MCP Servers.
+
+MCP Registry server.json (application/mcp-server+json) — an
+installable package descriptor (package coordinates, transports,
+environment variables, CLI arguments).
+
+These are different artifacts, so they use different media types. The
+Server Card deliberately uses application/mcp-server-card+json (not
+application/mcp-server+json) to leave the unqualified mcp-server
+name for the Registry server.json document
+(modelcontextprotocol/experimental-ext-server-card issue #9 / PR #18).
+A catalog entry references whichever artifact fits the use case — a
+server.json for installable packages, a Server Card for connectable
+endpoints — and a domain MAY list both.
+
+Overview
+
+The MCP Registry defines a server.json format for describing MCP
+servers. Each server.json document captures everything needed to
+install, configure, and connect to a single MCP server: package
+coordinates (npm, PyPI, NuGet, OCI), remote endpoints (streamable-http,
+SSE), transport configuration, environment variables, and CLI arguments.
+
+In AI Catalog terms, a server.json document is the artifact
+content — the native metadata that a Catalog Entry references, declared
+with the known type application/mcp-server+json. AI Catalog does not
+duplicate or redefine server.json fields; it provides the discovery and
+trust layer that server.json does not address.
+
+Conceptual Mapping
+
+MCP server.json
+
+AI Catalog Equivalent
+
+server.json document (whole file)
+
+Artifact content via entry url (type application/mcp-server+json) or data
+
+name (reverse-DNS identifier)
+
+Entry identifier (mapped to the urn:air:{publisher}:{namespace}:{name} URN form — e.g. registry name com.pulsemcp/remote-filesystem → urn:air:pulsemcp.com:mcp:remote-filesystem). The mapping is not a mechanical transliteration: publisher is the publisher's actual domain (e.g. pulsemcp.com) and namespace is a chosen category (e.g. mcp), independent of the registry name's reverse-DNS segments.
+
+title
+
+Stays in the artifact (server.json carries its own title); entry displayName is omitted unless the artifact lacks a name
+
+description
+
+Entry description
+
+version
+
+Entry version
+
+repository
+
+Entry metadata.repository
+
+packages[] (npm, pypi, nuget, oci)
+
+Inside the artifact — not surfaced in the catalog
+
+remotes[] (streamable-http, sse)
+
+Inside the artifact — not surfaced in the catalog
+
+environmentVariables[]
+
+Inside the artifact — not surfaced in the catalog
+
+_meta
+
+Entry metadata for catalog-level hints; otherwise stays in the artifact
+
+(not in server.json)
+
+Entry publisher
+
+(not in server.json)
+
+Entry trustManifest (identity, attestations, provenance)
+
+(not in server.json)
+
+Entry tags for cross-artifact discovery
+
+MCP Server as Catalog Entry
+
+An MCP server published as a Registry server.json maps to a Catalog
+Entry whose url points to the server.json document and whose type
+is the known type application/mcp-server+json:
+
+{
+"identifier": "urn:air:pulsemcp.com:mcp:remote-filesystem",
+"version": "0.1.5",
+"type": "application/mcp-server+json",
+"url": "https://registry.modelcontextprotocol.io/v0/servers/com.pulsemcp%2Fremote-filesystem/versions/0.1.5",
+"description": "MCP server for remote filesystem operations on cloud storage",
+"tags": ["filesystem", "storage"],
+"publisher": {
+"identifier": "did:web:pulsemcp.com",
+"displayName": "PulseMCP"
+},
+"trustManifest": {
+"identity": "urn:air:pulsemcp.com:mcp:remote-filesystem",
+"attestations": [
+{
+"type": "publisher-identity",
+"uri": "https://trust.pulsemcp.com/certs/publisher.jwt"
+}
+],
+"provenance": [
+{
+"relation": "publishedFrom",
+"sourceId": "https://github.com/pulsemcp/mcp-servers",
+"registryUri": "https://registry.npmjs.org"
+}
+]
+},
+"metadata": {
+"repository": "https://github.com/pulsemcp/mcp-servers"
+},
+"updatedAt": "2026-03-15T10:00:00Z"
+}
+
+The url resolves to the server's server.json. In the MCP Registry, a
+specific version is addressed as
+/v0/servers/{name}/versions/{version} — where {name} is the server's
+reverse-DNS registry name, URL-encoded (the / between namespace and
+name becomes %2F) — and the response carries the server.json document
+in its server field alongside registry _meta. A client fetches the
+catalog entry for discovery and trust evaluation, then retrieves the
+server.json for operational details (packages, transports, env vars).
+
+MCP Registry as AI Catalog
+
+The MCP Registry — a centralized index of MCP servers — can be
+represented as an AI Catalog. This lets clients that understand
+application/ai-catalog+json discover installable MCP servers alongside
+A2A agents, skills, and other artifacts:
+
+{
+"specVersion": "1.0",
+"host": {
+"displayName": "MCP Server Registry",
+"identifier": "did:web:modelcontextprotocol.io",
+"documentationUrl": "https://modelcontextprotocol.io/docs"
+},
+"entries": [
+{
+"identifier": "urn:air:pulsemcp.com:mcp:remote-filesystem",
+"version": "0.1.5",
+"type": "application/mcp-server+json",
+"url": "https://registry.modelcontextprotocol.io/v0/servers/com.pulsemcp%2Fremote-filesystem/versions/0.1.5",
+"description": "MCP server for remote filesystem operations on cloud storage",
+"tags": ["filesystem", "storage"]
+},
+{
+"identifier": "urn:air:pulsemcp.com:mcp:pulse-fetch",
+"version": "0.2.14",
+"type": "application/mcp-server+json",
+"url": "https://registry.modelcontextprotocol.io/v0/servers/com.pulsemcp.servers%2Fpulse-fetch/versions/0.2.14",
+"description": "MCP server that extracts clean, structured content from web pages",
+"tags": ["fetch", "web"]
+}
+]
+}
+
+Relationship to MCP Server Cards
+
+A Registry server.json and an MCP Server Card describe the same kind of
+thing at different lifecycle stages, and they layer naturally:
+
+server.json (application/mcp-server+json)
+
+How do I install and configure this server? What packages,
+transports, arguments, and environment variables does it need?
+
+Server Card (application/mcp-server-card+json)
+
+How do I connect to and use this running server? What transport
+endpoint, capabilities, tools, and authentication does it expose?
+
+A domain MAY publish both as separate catalog entries — one entry of each
+type pointing at the respective artifact — so clients can pick the
+representation that matches what they are doing (provisioning vs.
+connecting). AI Catalog provides the trust and cross-ecosystem indexing
+layer over both; each artifact carries its own protocol-specific detail.
 
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