--- a/base/rendered.txt
+++ b/head/rendered.txt
@@ -142,7 +142,7 @@
 {
 "identifier": "urn:air:example.com:mcp:weather",
 "type": "application/mcp-server-card+json",
-"url": "https://api.example.com/.well-known/mcp/server-card.json"
+"url": "https://api.example.com/mcp/server-card"
 },
 {
 "identifier": "urn:air:example.com:a2a:research",
@@ -1498,7 +1498,7 @@
 "identifier": "urn:air:acme.com:server:finance-mcp",
 "version": "1.4.0",
 "type": "application/mcp-server-card+json",
-"url": "https://api.acme-corp.com/.well-known/mcp/server-card.json",
+"url": "https://api.acme-corp.com/mcp/server-card",
 "description": "MCP server with finance tools.",
 "tags": ["finance", "mcp"],
 "updatedAt": "2026-03-15T10:00:00Z"
@@ -1520,7 +1520,7 @@
 {
 "identifier": "urn:air:acme.com:server:finance-mcp",
 "type": "application/mcp-server-card+json",
-"url": "https://api.acme-corp.com/.well-known/mcp/server-card.json"
+"url": "https://api.acme-corp.com/mcp/server-card"
 },
 {
 "identifier": "urn:air:acme.com:data:market-2026q1",
@@ -1624,7 +1624,7 @@
 {
 "identifier": "urn:air:acme.com:agent:finance:mcp",
 "type": "application/mcp-server-card+json",
-"url": "https://api.acme-corp.com/.well-known/mcp/server-card.json"
+"url": "https://api.acme-corp.com/mcp/server-card"
 },
 {
 "identifier": "urn:air:acme.com:agent:finance:a2a",
@@ -1912,268 +1912,34 @@
 losslessly, allowing simple consumers to work with the logical format
 while infrastructure-oriented deployments leverage OCI distribution.
 
-Mapping to MCP Registry server.json
-
-This appendix describes how the MCP Registry server.json format
-(see modelcontextprotocol/registry)
-relates to AI Catalog, enabling MCP servers to be discovered alongside
-other AI artifacts through a unified catalog.
-
-Note: The MCP ecosystem defines two distinct metadata documents
-for servers. The Registry server.json is an installable package
-descriptor (package coordinates, transports, environment variables).
-The MCP Server Card (SEP-1649)
-is a runtime discovery document at /.well-known/mcp/server-card.json
-describing capabilities, tools, and authentication. An AI Catalog
-entry can reference either artifact depending on the use case — use
-server.json for installable packages and Server Cards for
-connectable HTTP endpoints.
+Mapping to MCP Servers
+
+This appendix describes how remote (HTTP-connectable) MCP servers
+map to AI Catalog, enabling them to be discovered alongside other AI
+artifacts through a unified catalog. The documented, supported path is
+to reference each server's MCP Server Card
+(SEP-2127)
+as the artifact content of a Catalog Entry.
+
+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.
 
 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. The
-AI Catalog does not duplicate or redefine server.json fields.
-Instead, 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 or data
-
-name (reverse-DNS identifier)
-
-Entry identifier (mapped to URI form)
-
-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 catalog
-
-remotes[] (streamable-http, sse)
-
-Inside the artifact — not surfaced in catalog
-
-environmentVariables[]
-
-Inside the artifact — not surfaced in catalog
-
-_meta
-
-Entry metadata for catalog-level hints; otherwise stays in 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 Registry (centralized service)
-
-AI Catalog (decentralized, any URL)
-
-Separation of Concerns
-
-The server.json format and AI Catalog address different concerns:
-
-server.json (Operational)
-
-How do I install this server? What packages, transports, arguments,
-and environment variables does it need?
-
-AI Catalog (Discovery + Trust)
-
-What servers exist? Who published them? Can I trust them? Where is
-their metadata?
-
-This separation means the AI Catalog entry is thin — it points at the
-server.json and adds only what server.json lacks: publisher
-identity, trust verification, and cross-ecosystem discoverability.
-
-MCP Server as Catalog Entry
-
-An MCP server listed in the Registry maps to a Catalog Entry whose
-url points to the server.json document and whose type
-reflects the Registry format:
-
-{
-"identifier": "urn:air:anonymous.modelcontextprotocol.io:mcp:brave-search",
-"version": "1.0.2",
-"type": "application/mcp-server-card+json",
-"url": "https://registry.modelcontextprotocol.io/servers/brave-search/server.json",
-"description": "MCP server for Brave Search API integration",
-"tags": ["search", "brave", "web"],
-"publisher": {
-"identifier": "did:web:modelcontextprotocol.io",
-"displayName": "Model Context Protocol"
-},
-"trustManifest": {
-"identity": "did:web:anonymous.modelcontextprotocol.io:mcp:brave-search",
-"attestations": [
-{
-"type": "publisher-identity",
-"uri": "https://registry.modelcontextprotocol.io/certs/publisher.jwt",
-"description": "Verifies did:web:modelcontextprotocol.io as publisher"
-}
-],
-"provenance": [
-{
-"relation": "publishedFrom",
-"sourceId": "https://github.com/modelcontextprotocol/servers",
-"registryUri": "https://registry.npmjs.org"
-}
-]
-},
-"metadata": {
-"repository": "https://github.com/modelcontextprotocol/servers"
-},
-"updatedAt": "2026-03-15T10:00:00Z"
-}
-
-The url points to the complete server.json. A client fetches the
-catalog entry for discovery and trust evaluation, then retrieves the
-server.json for operational details (packages, transports, env vars).
-
-Note: This example uses application/json because the MCP
-Registry has not registered a dedicated media type for server.json.
-When referencing an MCP Server Card (SEP-1649) instead, use
-application/mcp-server-card+json — see
-Relationship to MCP Server Cards.
-
-MCP Registry as AI Catalog
-
-The MCP Registry — a centralized index of MCP servers — can be
-represented as an AI Catalog. This enables clients that understand
-application/ai-catalog+json to discover 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:anonymous.modelcontextprotocol.io:mcp:brave-search",
-"version": "1.0.2",
-"type": "application/mcp-server-card+json",
-"url": "https://registry.modelcontextprotocol.io/servers/brave-search/server.json",
-"description": "MCP server for Brave Search API integration",
-"tags": ["search", "brave"]
-},
-{
-"identifier": "urn:air:modelcontextprotocol.github.io:mcp:filesystem",
-"version": "1.0.2",
-"type": "application/mcp-server-card+json",
-"url": "https://registry.modelcontextprotocol.io/servers/filesystem/server.json",
-"description": "MCP server for filesystem operations",
-"tags": ["filesystem", "files"]
-},
-{
-"identifier": "urn:air:example.github.io:mcp:weather-mcp",
-"version": "0.5.0",
-"type": "application/mcp-server-card+json",
-"url": "https://registry.modelcontextprotocol.io/servers/weather/server.json",
-"description": "Python MCP server for weather data access",
-"tags": ["weather", "python"],
-"publisher": {
-"identifier": "did:web:example.github.io",
-"displayName": "Example Corp"
-}
-}
-]
-}
-
-Decentralized Discovery
-
-The MCP Registry is a centralized service. AI Catalog enables
-decentralized discovery: any domain can publish its MCP servers at
-/.well-known/ai-catalog.json without registering with a central
-authority.
-
-A vendor hosting its own MCP servers can publish:
-
-https://api.acme-corp.com/.well-known/ai-catalog.json
-
-Clients and crawlers discover the catalog via the well-known URL,
-find entries by type, and fetch the referenced artifacts for
-operational details — whether those are MCP Server Cards, Registry
-server.json documents, or other AI artifact formats.
-
-The centralized MCP Registry and decentralized AI Catalogs are
-complementary. The registry can serve an AI Catalog as its response
-format, while individual domains publish their own catalogs for
-direct discovery.
-
-What AI Catalog Adds to server.json
-
-The server.json format has no trust or identity layer. AI Catalog
-fills this gap:
-
-Publisher identity: Verifiable publisher with DID or domain
-anchor, absent from server.json.
-
-Trust verification: Attestations (SOC2, HIPAA, publisher
-identity proofs) via the Trust Manifest.
-
-Provenance: Links to source repositories, registries, and
-build artifacts with cryptographic digests.
-
-Signing: Detached JWS signature on the Trust Manifest for
-integrity verification.
-
-Cross-ecosystem discovery: MCP servers become discoverable
-alongside A2A agents, plugins, and datasets through a single
-catalog format.
-
-Composability: MCP servers can be packaged with related
-artifacts (A2A agents, datasets) in nested catalogs.
-
-Relationship to MCP Server Cards (SEP-1649)
-
-MCP Server Cards
-(SEP-1649)
-define a static discovery document for individual HTTP-based MCP
-servers at /.well-known/mcp/server-card.json. A Server Card mirrors
-the MCP initialization handshake response: it carries the server's
-name, version, transport configuration, capabilities, authentication
-requirements, and optionally the full list of tools, resources, and
-prompts.
+An MCP Server Card is a static discovery document for an individual
+HTTP-based MCP server, describing its identity and how to connect to it.
+A Catalog Entry references the card wherever the server publishes it, as
+in the examples below. See
+SEP-2127
+for the Server Card's schema, fields, and hosting conventions.
+
+In AI Catalog terms, the Server Card is the artifact content — the
+native metadata that a Catalog Entry references via its url, declared
+with the known type application/mcp-server-card+json. The AI Catalog
+does not duplicate or redefine Server Card fields; it provides the
+discovery and trust layer that the Server Card does not address.
 
 AI Catalog and MCP Server Cards address different layers of discovery:
 
@@ -2189,13 +1955,63 @@
 trust them? What other artifact types are available alongside MCP
 servers?
 
-The two mechanisms layer naturally. An AI Catalog entry for an MCP
-server can reference the Server Card as its artifact content:
+Conceptual Mapping
+
+MCP Server Card
+
+AI Catalog Equivalent
+
+Server Card document (whole file)
+
+Artifact content via entry url (type application/mcp-server-card+json) or data
+
+Server name (reverse-DNS identifier)
+
+Entry identifier (mapped to the urn:air:{publisher}:{namespace}:{name} URN form — e.g. urn:air:example.com:mcp:finance-server)
+
+title
+
+Stays in the Server Card (which carries its own title); entry displayName is omitted unless the artifact lacks a name
+
+description
+
+Entry description
+
+version
+
+Entry version
+
+transport / capabilities / tools / resources / auth
+
+Inside the Server Card — not surfaced in the catalog
+
+repository
+
+Entry metadata.repository
+
+(not in the Server Card)
+
+Entry publisher
+
+(not in the Server Card)
+
+Entry trustManifest (identity, attestations, provenance)
+
+(not in the Server Card)
+
+Entry tags for cross-artifact discovery
+
+MCP Server as Catalog Entry
+
+A remote MCP server maps to a Catalog Entry whose url points to the
+server's Server Card and whose type is the known type
+application/mcp-server-card+json:
 
 {
 "identifier": "urn:air:example.com:mcp:finance-server",
+"version": "1.0.2",
 "type": "application/mcp-server-card+json",
-"url": "https://api.acme-corp.com/.well-known/mcp/server-card.json",
+"url": "https://api.acme-corp.com/mcp/server-card",
 "description": "MCP server for financial data and trading tools",
 "tags": ["finance", "mcp"],
 "publisher": {
@@ -2218,12 +2034,75 @@
 }
 }
 
+Note on type: The type member is an open-text type identifier
+(ADR 0014);
+any string is accepted, with a recommended set of "known types." The
+known type for an MCP server referenced by its Server Card is
+application/mcp-server-card+json. Note the deliberate naming
+distinction: the MCP Server Card extension uses
+application/mcp-server-card+json (not application/mcp-server+json)
+to avoid colliding with the MCP Registry's server.json concept
+(modelcontextprotocol/experimental-ext-server-card issue #9 / PR #18).
+
+MCP Servers as an AI Catalog
+
+A domain that hosts remote MCP servers can publish them as an AI Catalog,
+letting clients that understand application/ai-catalog+json discover
+those servers alongside A2A agents, skills, and other artifacts. Each
+entry points to a server's Server Card:
+
+{
+"specVersion": "1.0",
+"host": {
+"displayName": "Acme MCP Servers",
+"identifier": "did:web:acme-corp.com",
+"documentationUrl": "https://acme-corp.com/docs"
+},
+"entries": [
+{
+"identifier": "urn:air:acme-corp.com:mcp:finance-server",
+"version": "1.0.2",
+"type": "application/mcp-server-card+json",
+"url": "https://api.acme-corp.com/finance/server-card",
+"description": "MCP server for financial data and trading tools",
+"tags": ["finance", "mcp"]
+},
+{
+"identifier": "urn:air:acme-corp.com:mcp:docs-search",
+"version": "1.0.2",
+"type": "application/mcp-server-card+json",
+"url": "https://api.acme-corp.com/docs-search/server-card",
+"description": "MCP server for searching internal documentation",
+"tags": ["search", "docs"]
+},
+{
+"identifier": "urn:air:acme-corp.com:mcp:ci-cd",
+"version": "0.5.0",
+"type": "application/mcp-server-card+json",
+"url": "https://api.acme-corp.com/ci-cd/server-card",
+"description": "MCP server for CI/CD pipeline operations",
+"tags": ["ci", "cd", "devops"]
+}
+]
+}
+
+Decentralized Discovery
+
+AI Catalog enables decentralized discovery: any domain can publish its
+MCP servers at /.well-known/ai-catalog.json without registering with a
+central authority.
+
+A vendor hosting its own MCP servers can publish:
+
+https://api.acme-corp.com/.well-known/ai-catalog.json
+
 A client discovering MCP servers follows this flow:
 
 Fetch /.well-known/ai-catalog.json to discover all artifacts on
 a domain (MCP servers, A2A agents, plugins, etc.).
 
-Filter entries by type to find MCP servers.
+Filter entries by type (application/mcp-server-card+json) to find
+MCP servers.
 
 Evaluate the Trust Manifest for publisher identity and attestations.
 
@@ -2238,6 +2117,30 @@
 protocol-specific operational details. A domain with multiple MCP
 servers publishes one AI Catalog listing all of them, with each entry
 pointing to its respective Server Card.
+
+What AI Catalog Adds
+
+A Server Card describes a single server but has no cross-server discovery
+or trust layer. AI Catalog fills this gap:
+
+Publisher identity: Verifiable publisher with DID or domain
+anchor.
+
+Trust verification: Attestations (SOC2, HIPAA, publisher
+identity proofs) via the Trust Manifest.
+
+Provenance: Links to source repositories, registries, and
+build artifacts with cryptographic digests.
+
+Signing: Detached JWS signature on the Trust Manifest for
+integrity verification.
+
+Cross-ecosystem discovery: MCP servers become discoverable
+alongside A2A agents, plugins, and datasets through a single
+catalog format.
+
+Composability: MCP servers can be packaged with related
+artifacts (A2A agents, datasets) in nested catalogs.
 
 Mapping to Claude Code Plugins Marketplace
 
