Add localization/theming feature to 0.3 version

MANIFEST.md

@@ -1,7 +1,7 @@
 # MCPB Manifest.json Spec
 
-Current version: `0.2`
+Current version: `0.3`
-Last updated: 2025-09-12
+Last updated: 2025-10-24
 
 ## Manifest Schema
 
@@ -11,7 +11,7 @@ A basic `manifest.json` with just the required fields looks like this:
 
 ```jsonc
 {
-  "manifest_version": "0.2", // Manifest spec version this manifest conforms to
+  "manifest_version": "0.3", // Manifest spec version this manifest conforms to
   "name": "my-extension", // Machine-readable name (used for CLI, APIs)
   "version": "1.0.0", // Semantic version of your extension
   "description": "A simple MCP extension", // Brief description of what the extension does
@@ -37,7 +37,7 @@ A basic `manifest.json` with just the required fields looks like this:
 
 ```json
 {
-  "manifest_version": "0.2",
+  "manifest_version": "0.3",
   "name": "my-extension",
   "version": "1.0.0",
   "description": "A simple MCP extension",
@@ -71,7 +71,7 @@ A full `manifest.json` with most of the optional fields looks like this:
 
 ```json
 {
-  "manifest_version": "0.1",
+  "manifest_version": "0.3",
   "name": "My MCP Extension",
   "display_name": "My Awesome MCP Extension",
   "version": "1.0.0",
@@ -90,10 +90,26 @@ A full `manifest.json` with most of the optional fields looks like this:
   "documentation": "https://docs.example.com/my-extension",
   "support": "https://github.com/your-username/my-extension/issues",
   "icon": "icon.png",
+  "icons": [
+    {
+      "src": "assets/icons/icon-16-light.png",
+      "sizes": "16x16",
+      "theme": "light"
+    },
+    {
+      "src": "assets/icons/icon-16-dark.png",
+      "sizes": "16x16",
+      "theme": "dark"
+    }
+  ],
   "screenshots": [
     "assets/screenshots/screenshot1.png",
     "assets/screenshots/screenshot2.png"
   ],
+  "localization": {
+    "resources": "resources/${locale}.json",
+    "default_locale": "en-US"
+  },
   "server": {
     "type": "node",
     "entry_point": "server/index.js",
@@ -221,6 +237,7 @@ A full `manifest.json` with most of the optional fields looks like this:
 ### Optional Fields
 
 - **icon**: Path to a png icon file, either relative in the package or a https:// url.
+- **icons**: Array of icon descriptors (`src`, `sizes`, optional `theme`) for light/dark or size-specific assets.
 - **display_name**: Human-friendly name for UI display
 - **long_description**: Detailed description for extension stores, markdown
 - **repository**: Source code repository information (type and url)
@@ -238,6 +255,38 @@ A full `manifest.json` with most of the optional fields looks like this:
 - **compatibility**: Compatibility requirements (client app version, platforms, and runtime versions)
 - **user_config**: User-configurable options for the extension (see User Configuration section)
 - **_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.
+- **localization**: Location of translated strings for user-facing fields (`resources` path containing a `${locale}` placeholder and `default_locale`).
+
+### Localization
+
+Provide localized strings without bloating the manifest by pointing to external per-locale resource files. A localization entry looks like this:
+
+```json
+"localization": {
+  "resources": "resources/${locale}.json",
+  "default_locale": "en-US"
+}
+```
+
+- `resources` must include a `${locale}` placeholder. Clients resolve it relative to the server install directory.
+- `default_locale` must be a valid [BCP 47](https://www.rfc-editor.org/rfc/bcp/bcp47.txt) identifier such as `en-US` or `zh-Hans`.
+- Values for the default locale stay in the main manifest; localized files only need to contain overrides.
+- When a translation is missing, clients fall back to the default locale value from the manifest.
+
+### Icons
+
+Use the `icons` array when you need multiple icon variants (different sizes or themes):
+
+```json
+"icons": [
+  { "src": "assets/icons/icon-16-light.png", "sizes": "16x16", "theme": "light" },
+  { "src": "assets/icons/icon-16-dark.png", "sizes": "16x16", "theme": "dark" }
+]
+```
+
+- `sizes` must be in `WIDTHxHEIGHT` form (e.g., `128x128`).
+- `theme` is optional; use values like `light`, `dark`, or platform-specific labels (e.g., `high-contrast`).
+- The legacy `icon` field remains supported for single assets—clients use it when `icons` is omitted.
 
 ## Compatibility
 

src/cli/init.ts

@@ -449,6 +449,58 @@ export async function promptVisualAssets() {
     },
   });
 
+  const addIconVariants = await confirm({
+    message: "Add theme/size-specific icons array?",
+    default: false,
+  });
+
+  const icons: Array<{
+    src: string;
+    sizes: string;
+    theme?: string;
+  }> = [];
+
+  if (addIconVariants) {
+    let addMoreIcons = true;
+    while (addMoreIcons) {
+      const iconSrc = await input({
+        message: "Icon source path (relative to manifest):",
+        validate: (value) => {
+          if (!value.trim()) return "Icon path is required";
+          if (value.includes("..")) return "Relative paths cannot include '..'";
+          return true;
+        },
+      });
+
+      const iconSizes = await input({
+        message: "Icon size (e.g., 16x16):",
+        validate: (value) => {
+          if (!value.trim()) return "Icon size is required";
+          if (!/^\d+x\d+$/.test(value)) {
+            return "Icon size must be in WIDTHxHEIGHT format (e.g., 128x128)";
+          }
+          return true;
+        },
+      });
+
+      const iconTheme = await input({
+        message: "Icon theme (light, dark, or custom - optional):",
+        default: "",
+      });
+
+      icons.push({
+        src: iconSrc,
+        sizes: iconSizes,
+        ...(iconTheme.trim() ? { theme: iconTheme.trim() } : {}),
+      });
+
+      addMoreIcons = await confirm({
+        message: "Add another icon entry?",
+        default: false,
+      });
+    }
+  }
+
   const addScreenshots = await confirm({
     message: "Add screenshots?",
     default: false,
@@ -475,7 +527,56 @@ export async function promptVisualAssets() {
     }
   }
 
-  return { icon, screenshots };
+  return { icon, icons, screenshots };
+}
+
+export async function promptLocalization() {
+  const configureLocalization = await confirm({
+    message: "Configure localization resources?",
+    default: false,
+  });
+
+  if (!configureLocalization) {
+    return undefined;
+  }
+
+  const placeholderRegex = /\$\{locale\}/i;
+
+  const resourcesPath = await input({
+    message: "Localization resources path (must include ${locale} placeholder):",
+    default: "resources/${locale}.json",
+    validate: (value) => {
+      if (!value.trim()) {
+        return "Resources path is required";
+      }
+      if (value.includes("..")) {
+        return "Relative paths cannot include '..'";
+      }
+      if (!placeholderRegex.test(value)) {
+        return "Path must include a ${locale} placeholder";
+      }
+      return true;
+    },
+  });
+
+  const defaultLocale = await input({
+    message: "Default locale (BCP 47, e.g., en-US):",
+    default: "en-US",
+    validate: (value) => {
+      if (!value.trim()) {
+        return "Default locale is required";
+      }
+      if (!/^[A-Za-z0-9]{2,8}(?:-[A-Za-z0-9]{1,8})*$/.test(value)) {
+        return "Default locale must follow BCP 47 (e.g., en-US or zh-Hans)";
+      }
+      return true;
+    },
+  });
+
+  return {
+    resources: resourcesPath,
+    default_locale: defaultLocale,
+  };
 }
 
 export async function promptCompatibility(
@@ -721,6 +822,11 @@ export function buildManifest(
   },
   visualAssets: {
     icon: string;
+    icons: Array<{
+      src: string;
+      sizes: string;
+      theme?: string;
+    }>;
     screenshots: string[];
   },
   serverConfig: {
@@ -767,6 +873,10 @@ export function buildManifest(
     license: string;
     repository?: { type: string; url: string };
   },
+  localization?: {
+    resources: string;
+    default_locale: string;
+  },
 ): McpbManifest {
   const { name, displayName, version, description, authorName } = basicInfo;
   const { authorEmail, authorUrl } = authorInfo;
@@ -791,9 +901,11 @@ export function buildManifest(
     ...(urls.documentation ? { documentation: urls.documentation } : {}),
     ...(urls.support ? { support: urls.support } : {}),
     ...(visualAssets.icon ? { icon: visualAssets.icon } : {}),
+    ...(visualAssets.icons.length > 0 ? { icons: visualAssets.icons } : {}),
     ...(visualAssets.screenshots.length > 0
       ? { screenshots: visualAssets.screenshots }
       : {}),
+    ...(localization ? { localization } : {}),
     server: {
       type: serverType,
       entry_point: entryPoint,
@@ -876,8 +988,11 @@ export async function initExtension(
       ? { homepage: "", documentation: "", support: "" }
       : await promptUrls();
     const visualAssets = nonInteractive
-      ? { icon: "", screenshots: [] }
+      ? { icon: "", icons: [], screenshots: [] }
       : await promptVisualAssets();
+    const localization = nonInteractive
+      ? undefined
+      : await promptLocalization();
     const serverConfig = nonInteractive
       ? getDefaultServerConfig(packageData)
       : await promptServerConfig(packageData);
@@ -910,6 +1025,7 @@ export async function initExtension(
       compatibility,
       userConfig,
       optionalFields,
+      localization,
     );
 
     // Write manifest

src/schemas/0.3.ts

@@ -3,6 +3,10 @@ import * as z from "zod";
 
 export const MANIFEST_VERSION = "0.3";
 
+const LOCALE_PLACEHOLDER_REGEX = /\$\{locale\}/i;
+const BCP47_REGEX = /^[A-Za-z0-9]{2,8}(?:-[A-Za-z0-9]{1,8})*$/;
+const ICON_SIZE_REGEX = /^\d+x\d+$/;
+
 export const McpServerConfigSchema = z.strictObject({
   command: z.string(),
   args: z.array(z.string()).optional(),
@@ -77,6 +81,35 @@ export const McpbUserConfigValuesSchema = z.record(
   z.union([z.string(), z.number(), z.boolean(), z.array(z.string())]),
 );
 
+export const McpbManifestLocalizationSchema = z.strictObject({
+  resources: z
+    .string()
+    .regex(
+      LOCALE_PLACEHOLDER_REGEX,
+      'resources must include a "${locale}" placeholder',
+    ),
+  default_locale: z
+    .string()
+    .regex(
+      BCP47_REGEX,
+      "default_locale must be a valid BCP 47 locale identifier",
+    ),
+});
+
+export const McpbManifestIconSchema = z.strictObject({
+  src: z.string(),
+  sizes: z
+    .string()
+    .regex(
+      ICON_SIZE_REGEX,
+      'sizes must be in the format "WIDTHxHEIGHT" (e.g., "16x16")',
+    ),
+  theme: z
+    .string()
+    .min(1, "theme cannot be empty when provided")
+    .optional(),
+});
+
 export const McpbManifestSchema = z
   .strictObject({
     $schema: z.string().optional(),
@@ -96,7 +129,9 @@ export const McpbManifestSchema = z
     documentation: z.string().url().optional(),
     support: z.string().url().optional(),
     icon: z.string().optional(),
+  icons: z.array(McpbManifestIconSchema).optional(),
     screenshots: z.array(z.string()).optional(),
+  localization: McpbManifestLocalizationSchema.optional(),
     server: McpbManifestServerSchema,
     tools: z.array(McpbManifestToolSchema).optional(),
     tools_generated: z.boolean().optional(),

src/schemas/latest.ts

@@ -1 +1 @@
-export * from "./0.2.js";
+export * from "./0.3.js";

src/schemas_loose/0.3.ts

@@ -0,0 +1,164 @@
+import * as z from "zod";
+
+export const MANIFEST_VERSION = "0.3";
+
+const LOCALE_PLACEHOLDER_REGEX = /\$\{locale\}/i;
+const BCP47_REGEX = /^[A-Za-z0-9]{2,8}(?:-[A-Za-z0-9]{1,8})*$/;
+const ICON_SIZE_REGEX = /^\d+x\d+$/;
+
+export const McpServerConfigSchema = z.object({
+  command: z.string(),
+  args: z.array(z.string()).optional(),
+  env: z.record(z.string(), z.string()).optional(),
+});
+
+export const McpbManifestAuthorSchema = z.object({
+  name: z.string(),
+  email: z.string().email().optional(),
+  url: z.string().url().optional(),
+});
+
+export const McpbManifestRepositorySchema = z.object({
+  type: z.string(),
+  url: z.string().url(),
+});
+
+export const McpbManifestPlatformOverrideSchema =
+  McpServerConfigSchema.partial();
+
+export const McpbManifestMcpConfigSchema = McpServerConfigSchema.extend({
+  platform_overrides: z
+    .record(z.string(), McpbManifestPlatformOverrideSchema)
+    .optional(),
+});
+
+export const McpbManifestServerSchema = z.object({
+  type: z.enum(["python", "node", "binary"]),
+  entry_point: z.string(),
+  mcp_config: McpbManifestMcpConfigSchema,
+});
+
+export const McpbManifestCompatibilitySchema = z
+  .object({
+    claude_desktop: z.string().optional(),
+    platforms: z.array(z.enum(["darwin", "win32", "linux"])).optional(),
+    runtimes: z
+      .object({
+        python: z.string().optional(),
+        node: z.string().optional(),
+      })
+      .optional(),
+  })
+  .passthrough();
+
+export const McpbManifestToolSchema = z.object({
+  name: z.string(),
+  description: z.string().optional(),
+});
+
+export const McpbManifestPromptSchema = z.object({
+  name: z.string(),
+  description: z.string().optional(),
+  arguments: z.array(z.string()).optional(),
+  text: z.string(),
+});
+
+export const McpbUserConfigurationOptionSchema = z.object({
+  type: z.enum(["string", "number", "boolean", "directory", "file"]),
+  title: z.string(),
+  description: z.string(),
+  required: z.boolean().optional(),
+  default: z
+    .union([z.string(), z.number(), z.boolean(), z.array(z.string())])
+    .optional(),
+  multiple: z.boolean().optional(),
+  sensitive: z.boolean().optional(),
+  min: z.number().optional(),
+  max: z.number().optional(),
+});
+
+export const McpbUserConfigValuesSchema = z.record(
+  z.string(),
+  z.union([z.string(), z.number(), z.boolean(), z.array(z.string())]),
+);
+
+export const McpbManifestLocalizationSchema = z
+  .object({
+    resources: z
+      .string()
+      .regex(
+        LOCALE_PLACEHOLDER_REGEX,
+        'resources must include a "${locale}" placeholder',
+      ),
+    default_locale: z
+      .string()
+      .regex(
+        BCP47_REGEX,
+        "default_locale must be a valid BCP 47 locale identifier",
+      ),
+  })
+  .passthrough();
+
+export const McpbManifestIconSchema = z
+  .object({
+    src: z.string(),
+    sizes: z
+      .string()
+      .regex(
+        ICON_SIZE_REGEX,
+        'sizes must be in the format "WIDTHxHEIGHT" (e.g., "16x16")',
+      ),
+    theme: z.string().min(1).optional(),
+  })
+  .passthrough();
+
+export const McpbManifestSchema = z
+  .object({
+    $schema: z.string().optional(),
+    dxt_version: z
+      .literal(MANIFEST_VERSION)
+      .optional()
+      .describe("@deprecated Use manifest_version instead"),
+    manifest_version: z.literal(MANIFEST_VERSION).optional(),
+    name: z.string(),
+    display_name: z.string().optional(),
+    version: z.string(),
+    description: z.string(),
+    long_description: z.string().optional(),
+    author: McpbManifestAuthorSchema,
+    repository: McpbManifestRepositorySchema.optional(),
+    homepage: z.string().url().optional(),
+    documentation: z.string().url().optional(),
+    support: z.string().url().optional(),
+    icon: z.string().optional(),
+    icons: z.array(McpbManifestIconSchema).optional(),
+    screenshots: z.array(z.string()).optional(),
+    localization: McpbManifestLocalizationSchema.optional(),
+    server: McpbManifestServerSchema,
+    tools: z.array(McpbManifestToolSchema).optional(),
+    tools_generated: z.boolean().optional(),
+    prompts: z.array(McpbManifestPromptSchema).optional(),
+    prompts_generated: z.boolean().optional(),
+    keywords: z.array(z.string()).optional(),
+    license: z.string().optional(),
+    privacy_policies: z.array(z.string().url()).optional(),
+    compatibility: McpbManifestCompatibilitySchema.optional(),
+    user_config: z
+      .record(z.string(), McpbUserConfigurationOptionSchema)
+      .optional(),
+    _meta: z.record(z.string(), z.record(z.string(), z.any())).optional(),
+  })
+  .passthrough()
+  .refine((data) => !!(data.dxt_version || data.manifest_version), {
+    message:
+      "Either 'dxt_version' (deprecated) or 'manifest_version' must be provided",
+  });
+
+export const McpbSignatureInfoSchema = z.object({
+  status: z.enum(["signed", "unsigned", "self-signed"]),
+  publisher: z.string().optional(),
+  issuer: z.string().optional(),
+  valid_from: z.string().optional(),
+  valid_to: z.string().optional(),
+  fingerprint: z.string().optional(),
+});

src/schemas_loose/index.ts

@@ -1,3 +1,4 @@
 export * as v0_1 from "./0.1.js";
 export * as v0_2 from "./0.2.js";
+export * as v0_3 from "./0.3.js";
 export * as latest from "./latest.js";

src/schemas_loose/latest.ts

@@ -1 +1 @@
-export * from "./0.2.js";
+export * from "./0.3.js";

src/shared/constants.ts

@@ -1,14 +1,16 @@
 import { McpbManifestSchema as ManifestSchemaV0_1 } from "../schemas/0.1.js";
 import { McpbManifestSchema as ManifestSchemaV0_2 } from "../schemas/0.2.js";
+import { McpbManifestSchema as ManifestSchemaV0_3 } from "../schemas/0.3.js";
 import { McpbManifestSchema as CurrentManifestSchema } from "../schemas/latest.js";
 import { McpbManifestSchema as LooseManifestSchemaV0_1 } from "../schemas_loose/0.1.js";
 import { McpbManifestSchema as LooseManifestSchemaV0_2 } from "../schemas_loose/0.2.js";
+import { McpbManifestSchema as LooseManifestSchemaV0_3 } from "../schemas_loose/0.3.js";
 import { McpbManifestSchema as CurrentLooseManifestSchema } from "../schemas_loose/latest.js";
 
 /**
  * Latest manifest version - the version that new manifests should use
  */
-export const LATEST_MANIFEST_VERSION = "0.2" as const;
+export const LATEST_MANIFEST_VERSION = "0.3" as const;
 
 /**
  * Map of manifest versions to their strict schemas
@@ -16,6 +18,7 @@ export const LATEST_MANIFEST_VERSION = "0.2" as const;
 export const MANIFEST_SCHEMAS = {
   "0.1": ManifestSchemaV0_1,
   "0.2": ManifestSchemaV0_2,
+  "0.3": ManifestSchemaV0_3,
 } as const;
 
 /**
@@ -24,6 +27,7 @@ export const MANIFEST_SCHEMAS = {
 export const MANIFEST_SCHEMAS_LOOSE = {
   "0.1": LooseManifestSchemaV0_1,
   "0.2": LooseManifestSchemaV0_2,
+  "0.3": LooseManifestSchemaV0_3,
 } as const;
 
 /**

test/config.test.ts

@@ -90,7 +90,7 @@ describe("getMcpConfigForManifest", () => {
   };
 
   const baseManifest: McpbManifest = {
-    manifest_version: "0.2",
+    manifest_version: "0.3",
     name: "test-extension",
     version: "1.0.0",
     description: "Test extension",
@@ -305,7 +305,7 @@ describe("getMcpConfigForManifest", () => {
 
 describe("hasRequiredConfigMissing", () => {
   const baseManifest: McpbManifest = {
-    manifest_version: "0.2",
+    manifest_version: "0.3",
     name: "test-extension",
     version: "1.0.0",
     description: "Test extension",

test/init.test.ts

@@ -194,6 +194,7 @@ describe("init functions", () => {
         },
         {
           icon: "",
+          icons: [],
           screenshots: [],
         },
         {
@@ -215,6 +216,7 @@ describe("init functions", () => {
           keywords: "",
           license: "",
         },
+        undefined,
       );
 
       expect(manifest).toEqual({
@@ -258,6 +260,10 @@ describe("init functions", () => {
         },
         {
           icon: "icon.png",
+          icons: [
+            { src: "assets/icons/icon-16-light.png", sizes: "16x16", theme: "light" },
+            { src: "assets/icons/icon-16-dark.png", sizes: "16x16", theme: "dark" },
+          ],
           screenshots: ["screen1.png", "screen2.png"],
         },
         {
@@ -301,6 +307,10 @@ describe("init functions", () => {
           license: "MIT",
           repository: { type: "git", url: "https://github.com/user/repo" },
         },
+        {
+          resources: "resources/${locale}.json",
+          default_locale: "en-US",
+        },
       );
 
       expect(manifest).toEqual({
@@ -320,7 +330,23 @@ describe("init functions", () => {
         documentation: "https://docs.example.com",
         support: "https://support.example.com",
         icon: "icon.png",
+        icons: [
+          {
+            src: "assets/icons/icon-16-light.png",
+            sizes: "16x16",
+            theme: "light",
+          },
+          {
+            src: "assets/icons/icon-16-dark.png",
+            sizes: "16x16",
+            theme: "dark",
+          },
+        ],
         screenshots: ["screen1.png", "screen2.png"],
+        localization: {
+          resources: "resources/${locale}.json",
+          default_locale: "en-US",
+        },
         server: {
           type: "python",
           entry_point: "server/main.py",

test/schemas.test.ts

@@ -1,7 +1,7 @@
 import { readFileSync } from "fs";
 import { join } from "path";
 
-import { McpbManifestSchema, v0_3 } from "../src/schemas/index.js";
+import { McpbManifestSchema, v0_2, v0_3 } from "../src/schemas/index.js";
 
 describe("McpbManifestSchema", () => {
   it("should validate a valid manifest", () => {
@@ -35,9 +35,26 @@ describe("McpbManifestSchema", () => {
     }
   });
 
+  it("should accept a 0.2 manifest when upgraded to 0.3", () => {
+    const manifestPath = join(__dirname, "valid-manifest-0.2.json");
+    const manifestContent = readFileSync(manifestPath, "utf-8");
+    const manifestData = JSON.parse(manifestContent);
+
+    const legacyResult = v0_2.McpbManifestSchema.safeParse(manifestData);
+    expect(legacyResult.success).toBe(true);
+
+    const upgradedManifest = {
+      ...manifestData,
+      manifest_version: "0.3",
+    };
+    const upgradedResult = v0_3.McpbManifestSchema.safeParse(upgradedManifest);
+
+    expect(upgradedResult.success).toBe(true);
+  });
+
   it("should validate manifest with all optional fields", () => {
     const fullManifest = {
-      manifest_version: "0.2",
+      manifest_version: "0.3",
       name: "full-extension",
       display_name: "Full Featured Extension",
       version: "2.0.0",
@@ -56,7 +73,23 @@ describe("McpbManifestSchema", () => {
       documentation: "https://docs.example.com",
       support: "https://support.example.com",
       icon: "icon.png",
+      icons: [
+        {
+          src: "assets/icons/icon-16-light.png",
+          sizes: "16x16",
+          theme: "light",
+        },
+        {
+          src: "assets/icons/icon-16-dark.png",
+          sizes: "16x16",
+          theme: "dark",
+        },
+      ],
       screenshots: ["screenshot1.png", "screenshot2.png"],
+      localization: {
+        resources: "resources/${locale}.json",
+        default_locale: "en-US",
+      },
       server: {
         type: "python",
         entry_point: "main.py",
@@ -109,6 +142,8 @@ describe("McpbManifestSchema", () => {
       expect(result.data.tools).toHaveLength(1);
       expect(result.data.compatibility?.platforms).toContain("darwin");
       expect(result.data.user_config?.api_key.type).toBe("string");
+      expect(result.data.icons).toHaveLength(2);
+      expect(result.data.localization?.default_locale).toBe("en-US");
     }
   });
 
@@ -117,7 +152,7 @@ describe("McpbManifestSchema", () => {
 
     serverTypes.forEach((type) => {
       const manifest = {
-        manifest_version: "0.2",
+        manifest_version: "0.3",
         name: "test",
         version: "1.0.0",
         description: "Test",
@@ -213,4 +248,92 @@ describe("McpbManifestSchema", () => {
     });
   });
 
+  describe("localization", () => {
+    const base = {
+      manifest_version: "0.3" as const,
+      name: "loc-ext",
+      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("requires a ${locale} placeholder", () => {
+      const manifest = {
+        ...base,
+        localization: {
+          resources: "resources/fr.json",
+          default_locale: "en-US",
+        },
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(false);
+      if (!result.success) {
+        const messages = result.error.issues.map((issue) => issue.message);
+        expect(messages.join(" ")).toContain("${locale}");
+      }
+    });
+
+    it("rejects invalid default locale", () => {
+      const manifest = {
+        ...base,
+        localization: {
+          resources: "resources/${locale}.json",
+          default_locale: "en_us",
+        },
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(false);
+    });
+
+    it("accepts valid localization settings", () => {
+      const manifest = {
+        ...base,
+        localization: {
+          resources: "resources/${locale}.json",
+          default_locale: "en-US",
+        },
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(true);
+    });
+  });
+
+  describe("icons", () => {
+    const base = {
+      manifest_version: "0.3" as const,
+      name: "icon-ext",
+      version: "1.0.0",
+      description: "Test manifest",
+      author: { name: "Author" },
+      server: {
+        type: "python" as const,
+        entry_point: "main.py",
+        mcp_config: { command: "python", args: ["main.py"] },
+      },
+    };
+
+    it("rejects icons with invalid size format", () => {
+      const manifest = {
+        ...base,
+        icons: [{ src: "assets/icon.png", sizes: "16", theme: "light" }],
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(false);
+    });
+
+    it("allows icons without theme", () => {
+      const manifest = {
+        ...base,
+        icons: [{ src: "assets/icon.png", sizes: "128x128" }],
+      };
+      const result = McpbManifestSchema.safeParse(manifest);
+      expect(result.success).toBe(true);
+    });
+  });
+
 });

test/valid-manifest-0.2.json

@@ -0,0 +1,21 @@
+{
+    "manifest_version": "0.2",
+    "name": "legacy-extension",
+    "display_name": "Legacy Extension",
+    "version": "1.0.0",
+    "description": "An extension that predates 0.3",
+    "author": {
+        "name": "Legacy Author",
+        "email": "legacy@example.com"
+    },
+    "server": {
+        "type": "node",
+        "entry_point": "server/index.js",
+        "mcp_config": {
+            "command": "node",
+            "args": [
+                "${__dirname}/server/index.js"
+            ]
+        }
+    }
+}

test/valid-manifest.json

@@ -1,5 +1,5 @@
 {
-  "manifest_version": "0.2",
+  "manifest_version": "0.3",
   "name": "test-extension",
   "display_name": "Test Extension",
   "version": "1.0.0",
@@ -13,7 +13,9 @@
     "entry_point": "server/index.js",
     "mcp_config": {
       "command": "node",
-      "args": ["${__dirname}/server/index.js"]
+      "args": [
+        "${__dirname}/server/index.js"
+      ]
     }
   }
 }