Refactor manifest schema to replace static_responses and client_extensions with _meta for improved organization

Author: asklar

MANIFEST.md

@@ -156,52 +156,52 @@ A full `manifest.json` with most of the optional fields looks like this:
       "max": 100
     }
   },
-  "static_responses": {
-    "initialize": {
-      "capabilities": {},
-      "instructions": "When the user wants to search files, use the search_files tool but only after asking them whether the files are local.",
-      "protocolVersion": "2025-06-18",
-      "serverInfo": {
-        "name": "MyMCPExtension",
-        "title": "My MCP Extension - Pro Edition",
-        "version": "1.0.0"
-      }
-    },
-    "tools/list": {
-      "tools": [
-        {
-          "name": "search_files",
-          "title": "File search",
-          "description": "Search for files in a directory",
-          "inputSchema": {
-            "type": "object",
-            "properties": {
-              "fileSpec": {
-                "type": "string",
-                "description": "The file name to search for. Wildcards are supported"
-              }
-            },
-            "required": ["fileSpec"]
-          },
-          "outputSchema": {
-            "type": "object",
-            "properties": {
-              "searchResults": {
-                "type": "array",
-                "description": "The list of file paths that were found",
-                "items": {
-                  "type": "string"
-                }
-              }
-            },
+  "_meta": {
+    "com.microsoft.windows": {
+      "package_family_name": "MyMcpMSIXPackage_51g09708xawrw",
+      "static_responses": {
+        "initialize": {
+          "capabilities": {},
+          "instructions": "When the user wants to search files, use the search_files tool but only after asking them whether the files are local.",
+          "protocolVersion": "2025-06-18",
+          "serverInfo": {
+            "name": "MyMCPExtension",
+            "title": "My MCP Extension - Pro Edition",
+            "version": "1.0.0"
           }
+        },
+        "tools/list": {
+          "tools": [
+            {
+              "name": "search_files",
+              "title": "File search",
+              "description": "Search for files in a directory",
+              "inputSchema": {
+                "type": "object",
+                "properties": {
+                  "fileSpec": {
+                    "type": "string",
+                    "description": "The file name to search for. Wildcards are supported"
+                  }
+                },
+                "required": ["fileSpec"]
+              },
+              "outputSchema": {
+                "type": "object",
+                "properties": {
+                  "searchResults": {
+                    "type": "array",
+                    "description": "The list of file paths that were found",
+                    "items": {
+                      "type": "string"
+                    }
+                  }
+                },
+              }
+            }
+          ]
         }
-      ]
-    }
-  },
-  "client_extensions": {
-    "windows": {
-      "package_family_name": "MyMcpMSIXPackage_51g09708xawrw"
+      },
     }
   }
 }
@@ -237,8 +237,7 @@ A full `manifest.json` with most of the optional fields looks like this:
 - **privacy_policies**: Array of URLs to privacy policies for external services that handle user data. Required when the extension connects to external services (first- or third-party) that process user data. Each URL should link to the respective service's privacy policy document
 - **compatibility**: Compatibility requirements (client app version, platforms, and runtime versions)
 - **user_config**: User-configurable options for the extension (see User Configuration section)
-- **static_responses**: A set of static response to protocol messages (for example, `initialize`, `tools/list`, etc.). This allows clients to avoid running a server when a static response is present (e.g. to get the set of tools with their input schemas). For more information, consult the [MCP specification](https://modelcontextprotocol.io/specification).
-- **client_extensions**: Platform-specific client integration metadata (e.g., Windows `package_family_name`, macOS bundle identifiers) enabling tighter OS/app store integration
+- **_meta**: Platform-specific client integration metadata (e.g., Windows `package_family_name`, macOS bundle identifiers) enabling tighter OS/app store integration. The keys in the `_meta` object are reverse-DNS namespaced, and the values are a dictionary of platform-specific metadata.
 
 ## Compatibility
 
@@ -598,8 +597,6 @@ These fields describe the tools and prompts your MCP server provides. For server
 
 Note: Resources are not included in the manifest because MCP resources are inherently dynamic - they represent URIs to data that the server discovers at runtime based on configuration, filesystem state, database connections, etc.
 
-You can provide richer static tools by adding an `tools/list` entry inside the `static_responses` object.
-
 ### Static Declaration
 
 For servers with a fixed set of capabilities, list them in arrays.
@@ -659,62 +656,3 @@ The `_generated` fields:
 
 This helps implementing apps understand that querying the server at runtime will reveal more capabilities than what's declared in the manifest.
 
-## Static responses
-
-Servers can provide clients with static responses to protocol messages. Static responses let clients short-circuit server startup for discovery or platform integration metadata.
-This is useful to obtain rich tool schema information, server instructions, protocol version that the server supports, etc.
-The `static_responses` object is a dictionary where the key is the name of an MCP JSON-RPC method. For more information, consult the [MCP specification](https://modelcontextprotocol.io/specification).
-
-If both the `tools/list` static response and the `tools` array are present, clients should use the tools described in `tools/list`.
-
-Example:
-
-```json
-{
-  "static_responses": {
-    "initialize": {
-      "capabilities": {},
-      "instructions": "When the user wants to search files, use the search_files tool but only after asking them whether the files are local.",
-      "protocolVersion": "2025-06-18",
-      "serverInfo": {
-        "name": "MyMCPExtension",
-        "title": "My MCP Extension - Pro Edition",
-        "version": "1.0.0"
-      }
-    },
-    "tools/list": {
-      "tools": [
-        {
-          "name": "search_files",
-          "title": "File search",
-          "description": "Search for files in a directory",
-          "inputSchema": {
-            "type": "object",
-            "properties": {
-              "fileSpec": {
-                "type": "string",
-                "description": "The file name to search for. Wildcards are supported"
-              }
-            },
-            "required": ["fileSpec"]
-          },
-          "outputSchema": {
-            "type": "object",
-            "properties": {
-              "searchResults": {
-                "type": "array",
-                "description": "The list of file paths that were found",
-                "items": {
-                  "type": "string"
-                }
-              }
-            },
-          }
-        }
-      ]
-    }
-  },
-}
-```
-
-

src/schemas-loose.ts

@@ -107,8 +107,7 @@ export const McpbManifestSchema = z
     user_config: z
       .record(z.string(), McpbUserConfigurationOptionSchema)
       .optional(),
-    static_responses: z.record(z.string(), z.any()).optional(),
-    client_extensions: z.record(z.string(), z.record(z.string(), z.any())).optional(),
+    _meta: z.record(z.string(), z.record(z.string(), z.any())).optional(),
   })
   .refine((data) => !!(data.dxt_version || data.manifest_version), {
     message:

src/schemas.ts

@@ -110,8 +110,7 @@ export const McpbManifestSchema = z
     user_config: z
       .record(z.string(), McpbUserConfigurationOptionSchema)
       .optional(),
-    static_responses: z.record(z.string(), z.any()).optional(),
-    client_extensions: z.record(z.string(), z.record(z.string(), z.any())).optional(),
+    _meta: z.record(z.string(), z.record(z.string(), z.any())).optional(),
   })
   .refine((data) => !!(data.dxt_version || data.manifest_version), {
     message:

test/schemas.test.ts

@@ -137,7 +137,7 @@ describe("McpbManifestSchema", () => {
     });
   });
 
-  describe("client_extensions", () => {
+  describe("_meta", () => {
     const base = {
       manifest_version: "0.2",
       name: "client-ext-test",
@@ -151,23 +151,23 @@ describe("McpbManifestSchema", () => {
       },
     };
 
-    it("accepts valid client_extensions object with nested dictionaries", () => {
+    it("accepts valid _meta object with nested dictionaries", () => {
       const manifest = {
         ...base,
-        client_extensions: {
-          windows: { package_family_name: "Pkg_123", channel: "stable" },
-          darwin: { bundle_id: "com.example.app", notarized: true },
+        _meta: {
+          "com.microsoft.windows": { package_family_name: "Pkg_123", channel: "stable" },
+          "com.apple.darwin": { bundle_id: "com.example.app", notarized: true },
         },
       };
       const result = McpbManifestSchema.safeParse(manifest);
       expect(result.success).toBe(true);
     });
 
-    it("rejects primitive value in client_extensions entry", () => {
+    it("rejects primitive value in _meta entry", () => {
       const manifest = {
         ...base,
-        client_extensions: {
-          windows: "raw-string" as unknown as Record<string, unknown>,
+        _meta: {
+          "com.microsoft.windows": "raw-string" as unknown as Record<string, unknown>,
         },
       };
       const result = McpbManifestSchema.safeParse(manifest);
@@ -178,113 +178,33 @@ describe("McpbManifestSchema", () => {
       }
     });
 
-    it("rejects array value in client_extensions entry", () => {
+    it("rejects array value in _meta entry", () => {
       const manifest = {
         ...base,
-        client_extensions: {
-          linux: [] as unknown as Record<string, unknown>,
+        _meta: {
+          "com.apple.darwin": [] as unknown as Record<string, unknown>,
         },
       };
       const result = McpbManifestSchema.safeParse(manifest);
       expect(result.success).toBe(false);
     });
 
-    it("rejects null value in client_extensions entry", () => {
+    it("rejects null value in _meta entry", () => {
       const manifest = {
         ...base,
-        client_extensions: {
+        _meta: {
           custom: null as unknown as Record<string, unknown>,
         },
       };
       const result = McpbManifestSchema.safeParse(manifest);
       expect(result.success).toBe(false);
     });
 
-    it("allows empty object for client_extensions", () => {
-      const manifest = { ...base, client_extensions: {} };
+    it("allows empty object for _meta", () => {
+      const manifest = { ...base, _meta: {} };
       const result = McpbManifestSchema.safeParse(manifest);
       expect(result.success).toBe(true);
     });
   });
 
-  describe("static_responses", () => {
-    const base = {
-      manifest_version: "0.2",
-      name: "static-resp-test",
-      version: "1.0.0",
-      description: "Test manifest",
-      author: { name: "Author" },
-      server: {
-        type: "node" as const,
-        entry_point: "server/index.js",
-        mcp_config: { command: "node", args: ["server/index.js"] },
-      },
-    };
-
-    it("accepts valid static_responses with object entries", () => {
-      const manifest = {
-        ...base,
-        static_responses: {
-          initialize: {
-            capabilities: {},
-            protocolVersion: "2025-06-18",
-            serverInfo: { name: "Test", version: "1.0.0" },
-          },
-          "tools/list": {
-            tools: [
-              {
-                name: "search_files",
-                description: "Search for files",
-                inputSchema: { type: "object", properties: { query: { type: "string" } } },
-              },
-            ],
-          },
-        },
-      };
-      const result = McpbManifestSchema.safeParse(manifest);
-      expect(result.success).toBe(true);
-    });
-
-    it("accepts primitive value in static_responses entry", () => {
-      const manifest = {
-        ...base,
-        static_responses: {
-          ping: "pong",
-          code: 200,
-          ok: true,
-        },
-      };
-      const result = McpbManifestSchema.safeParse(manifest);
-      expect(result.success).toBe(true);
-    });
-
-    it("accepts array value in static_responses entry", () => {
-      const manifest = {
-        ...base,
-        static_responses: {
-          list: [1, 2, 3],
-        },
-      };
-      const result = McpbManifestSchema.safeParse(manifest);
-      expect(result.success).toBe(true);
-    });
-
-    it("accepts null value in static_responses entry", () => {
-      const manifest = {
-        ...base,
-        static_responses: {
-          initialize: null,
-        },
-      };
-      const result = McpbManifestSchema.safeParse(manifest);
-      expect(result.success).toBe(true);
-    });
-
-    it("allows empty object for static_responses", () => {
-      const manifest = { ...base, static_responses: {} };
-      const result = McpbManifestSchema.safeParse(manifest);
-      expect(result.success).toBe(true);
-    });
-  });
 });
-