Make the extension card-only: remove registry Server/package types

README.md

@@ -2,7 +2,7 @@
 
 > #### **Status:** Experimental. This work is for prototyping and feedback only, and is not an accepted or official MCP extension.
 
-This repository defines a TypeScript source-of-truth and generated JSON Schema for **MCP Server Cards** — a static metadata document that describes a remote MCP server enough for clients to discover and connect to it before initialization.
+This repository defines a TypeScript source-of-truth and generated JSON Schema for **MCP Server Cards**. Server Cards are a static metadata document that describes a remote MCP server enough for clients to discover and connect to it before initialization.
 
 It tracks [SEP-2127](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/2127) and is intended to be lifted directly into the main spec when Server Cards graduate (see [Graduation plan](#graduation-plan) below).
 
@@ -16,9 +16,13 @@ A **Server Card** is a JSON document — hosted at any unreserved URI, with `GET
 - Its remote transport endpoints (URLs, headers, variable templates, supported protocol versions)
 - Optional registry-style extension metadata (`_meta`)
 
-The companion **Server** document is a strict superset that adds locally-runnable `packages` — it is the shape the [MCP Registry](https://github.com/modelcontextprotocol/registry) uses for `server.json`.
+Server Cards intentionally omit primitive listings (tools, resources, prompts) — those remain subject to runtime listing via the protocol's standard list operations. They also intentionally omit local installation metadata — see [Relationship to the MCP Registry](#relationship-to-the-mcp-registry).
 
-Server Cards intentionally omit primitive listings (tools, resources, prompts) — those remain subject to runtime listing via the protocol's standard list operations.
+## Relationship to the MCP Registry
+
+A Server Card describes **remote connectivity only**. Metadata for locally-installable servers, packages, registries (npm, PyPI, OCI, NuGet, MCPB), runtime hints, command-line arguments, environment variables, lives in the [MCP Registry](https://github.com/modelcontextprotocol/registry)'s [`server.json` schema](https://github.com/modelcontextprotocol/registry/blob/main/docs/reference/server-json/generic-server-json.md), which is owned by the registry, not by this extension.
+
+Vendors who genuinely need to attach install hints to a Server Card can use namespaced [`_meta`](https://modelcontextprotocol.io/specification/latest/basic#meta) extension metadata, which remains the card's extension point.
 
 ## Layout
 
@@ -30,7 +34,6 @@ scripts/
   validate-examples.ts       # Validates examples/ against the generated schema
 examples/
   ServerCard/{valid,invalid} # Example Server Card documents
-  Server/{valid,invalid}     # Example Server (registry-shaped) documents
 ```
 
 The generated `schema.json` is checked into the repo so consumers can grab it without running the toolchain.
@@ -55,14 +58,14 @@ The `$schema` field on every document MUST be a URL of the form:
 https://static.modelcontextprotocol.io/schemas/v1/<name>.schema.json
 ```
 
-Schema URLs are versioned by their `vN` segment rather than by date, so additive revisions of the v1 shape don't bump every published document's `$schema`. Breaking changes would publish a `v2` family.
+Schema URLs are versioned by their `vN` segment. Server Card objects are closed (`additionalProperties: false`): a document using a field the schema doesn't declare is rejected, and vendor-specific data belongs in namespaced `_meta`, which stays open. Once `v1` is published a breaking revision of the shape would publish a new `vN` family rather than mutating `v1` in place. The `v1` shape is still pre-release and card-only — it intentionally does not include the registry-shaped `Server` / `packages` types.
 
 ## Graduation plan
 
 When the SEP is accepted and Server Cards graduate from this experimental extension:
 
 1. The contents of `schema.ts` in this repo move into `schema/draft/schema.ts` of [`modelcontextprotocol/modelcontextprotocol`](https://github.com/modelcontextprotocol/modelcontextprotocol). The two `MetaObject` and `Icon` definitions inlined here at the bottom of `schema.ts` already exist in the main spec and are dropped from the migration.
-2. The main spec's existing `scripts/generate-schemas.ts` regenerates `schema/draft/schema.json` (and downstream `docs/specification/draft/schema.mdx`) — no per-extension generator is required there.
+2. The main spec's existing `scripts/generate-schemas.ts` regenerates `schema/draft/schema.json` (and downstream `docs/specification/draft/schema.mdx`) — no per-extension generator is required there. One caveat: this repo passes `--noExtraProps` to `typescript-json-schema`, which is what makes Server Card objects closed (`additionalProperties: false`) and rejects registry-style `packages` documents. The main spec's generator does not use that flag, so the closed-object behavior must be carried over (or re-expressed) during migration — otherwise the graduated schema would silently accept unknown properties again.
 3. Published documents update their `$schema` to point at the main spec's hosted schema URL (e.g., `https://static.modelcontextprotocol.io/schemas/v1/server-card.schema.json` served from `modelcontextprotocol/static`).
 4. This repository is archived with a pointer to the relevant section of `schema/draft/schema.ts` in the main spec.
 

examples/ServerCard/invalid/with-packages.json

@@ -0,0 +1,19 @@
+{
+  "$schema": "https://static.modelcontextprotocol.io/schemas/v1/server-card.schema.json",
+  "name": "example-org/with-packages",
+  "version": "0.4.2",
+  "description": "Package metadata belongs to the registry's server.json, not a Server Card.",
+  "remotes": [
+    {
+      "type": "streamable-http",
+      "url": "https://example.com/mcp"
+    }
+  ],
+  "packages": [
+    {
+      "registryType": "npm",
+      "identifier": "@example-org/with-packages",
+      "transport": { "type": "stdio" }
+    }
+  ]
+}

examples/ServerCard/invalid/wrong-schema-name.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "https://static.modelcontextprotocol.io/schemas/v1/server.schema.json",
+  "name": "example-org/wrong-schema-name",
+  "version": "1.0.0",
+  "description": "References the removed registry server.json schema; only server-card.schema.json is valid in v1."
+}