Add static_responses and client_extensions to manifest schema and tests

MANIFEST.md

@@ -155,6 +155,54 @@ A full `manifest.json` with most of the optional fields looks like this:
       "min": 1,
       "max": 100
     }
+  },
+  "static_responses": {
+    "initialize": {
+      "capabilities": {},
+      "instructions": "Consider whether the user doesn't like puppies - if they don't, don't use the search_files tool.",
+      "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"
+    }
   }
 }
 ```
@@ -189,6 +237,8 @@ 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
 
 ## Compatibility
 
@@ -548,6 +598,8 @@ 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.
@@ -606,3 +658,63 @@ The `_generated` fields:
 - **prompts_generated**: Server generates additional prompts beyond those listed (default: false)
 
 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": "Consider whether the user doesn't like puppies - if they don't, don't use the search_files tool.",
+      "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

@@ -107,6 +107,8 @@ 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(),
   })
   .refine((data) => !!(data.dxt_version || data.manifest_version), {
     message:

src/schemas.ts

@@ -100,7 +100,7 @@ export const McpbManifestSchema = z
     screenshots: z.array(z.string()).optional(),
     server: McpbManifestServerSchema,
     tools: z.array(McpbManifestToolSchema).optional(),
-    tools_generated: z.boolean().optional(),
+    tools_generated: z.boolean().optional(),  
     prompts: z.array(McpbManifestPromptSchema).optional(),
     prompts_generated: z.boolean().optional(),
     keywords: z.array(z.string()).optional(),
@@ -110,6 +110,8 @@ 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(),
   })
   .refine((data) => !!(data.dxt_version || data.manifest_version), {
     message:

test/schemas.test.ts

@@ -136,4 +136,155 @@ describe("McpbManifestSchema", () => {
       expect(result.success).toBe(true);
     });
   });
+
+  describe("client_extensions", () => {
+    const base = {
+      manifest_version: "0.2",
+      name: "client-ext-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 client_extensions 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 },
+        },
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(true);
+    });
+
+    it("rejects primitive value in client_extensions entry", () => {
+      const manifest = {
+        ...base,
+        client_extensions: {
+          windows: "raw-string" as unknown as Record<string, unknown>,
+        },
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        const messages = result.error.issues.map((i) => i.message).join("\n");
+        expect(messages).toMatch(/Expected object/);
+      }
+    });
+
+    it("rejects array value in client_extensions entry", () => {
+      const manifest = {
+        ...base,
+        client_extensions: {
+          linux: [] as unknown as Record<string, unknown>,
+        },
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(false);
+    });
+
+    it("rejects null value in client_extensions entry", () => {
+      const manifest = {
+        ...base,
+        client_extensions: {
+          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: {} };
+      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);
+    });
+  });
 });
+