feat: add UV runtime support in manifest v0.4

Add UV as a new server type for Python extensions that use UV runtime
for dependency management instead of bundling dependencies.

Schema changes (v0.4):
- Add "uv" to server.type enum
- Make mcp_config optional (not needed for UV type)
- UV extensions rely on pyproject.toml for dependencies

Documentation:
- Add UV runtime section to MANIFEST.md explaining benefits and usage
- Update README.md to recommend UV runtime for Python
- Add complete hello-world-uv example

Benefits of UV runtime:
- Cross-platform support (Windows/macOS/Linux, Intel/ARM)
- Small bundle size (~100 KB vs 5-10 MB)
- Handles compiled dependencies portably
- No user Python installation required

Example manifest:
{
  "manifest_version": "0.4",
  "server": {
    "type": "uv",
    "entry_point": "src/server.py"
  }
}

Co-authored-by: Joan <joan@anthropic.com>

src/schemas/0.4.ts

@@ -0,0 +1,145 @@
+// v0.4: Adds UV runtime support for Python extensions
+import * as z from "zod";
+
+export const MANIFEST_VERSION = "0.4";
+
+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(),
+  env: z.record(z.string(), z.string()).optional(),
+});
+
+export const McpbManifestAuthorSchema = z.strictObject({
+  name: z.string(),
+  email: z.string().email().optional(),
+  url: z.string().url().optional(),
+});
+
+export const McpbManifestRepositorySchema = z.strictObject({
+  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.strictObject({
+  type: z.enum(["python", "node", "binary", "uv"]),
+  entry_point: z.string(),
+  // mcp_config is optional for UV type (UV handles execution)
+  mcp_config: McpbManifestMcpConfigSchema.optional(),
+});
+
+export const McpbManifestCompatibilitySchema = z.strictObject({
+  claude_desktop: z.string().optional(),
+  platforms: z.array(z.enum(["darwin", "win32", "linux"])).optional(),
+  runtimes: z
+    .strictObject({
+      python: z.string().optional(),
+      node: z.string().optional(),
+    })
+    .optional(),
+});
+
+export const McpbManifestToolSchema = z.strictObject({
+  name: z.string(),
+  description: z.string().optional(),
+});
+
+export const McpbManifestPromptSchema = z.strictObject({
+  name: z.string(),
+  description: z.string().optional(),
+  arguments: z.array(z.string()).optional(),
+  text: z.string(),
+});
+
+export const McpbUserConfigurationOptionSchema = z.strictObject({
+  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 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(),
+  size: z
+    .string()
+    .regex(
+      ICON_SIZE_REGEX,
+      'size 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(),
+    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(),
+  })
+  .refine((data) => !!(data.dxt_version || data.manifest_version), {
+    message:
+      "Either 'dxt_version' (deprecated) or 'manifest_version' must be provided",
+  });

src/schemas/any.ts

@@ -3,13 +3,15 @@ import * as z from "zod";
 import * as v0_1 from "./0.1.js";
 import * as v0_2 from "./0.2.js";
 import * as v0_3 from "./0.3.js";
+import * as v0_4 from "./0.4.js";
 
 /**
- * Union schema that accepts any supported manifest version (0.1, 0.2, 0.3).
+ * Union schema that accepts any supported manifest version.
  * Use this when you need to validate manifests of any version.
  */
 export const McpbManifestSchema = z.union([
   v0_1.McpbManifestSchema,
   v0_2.McpbManifestSchema,
   v0_3.McpbManifestSchema,
+  v0_4.McpbManifestSchema,
 ]);

src/schemas/index.ts

@@ -1,10 +1,12 @@
 import { McpbManifestSchema as ManifestSchemaV0_1 } from "./0.1.js";
 import { McpbManifestSchema as ManifestSchemaV0_2 } from "./0.2.js";
 import { McpbManifestSchema as ManifestSchemaV0_3 } from "./0.3.js";
+import { McpbManifestSchema as ManifestSchemaV0_4 } from "./0.4.js";
 
 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 v0_4 from "./0.4.js";
 export * as vAny from "./any.js";
 
 /**
@@ -14,4 +16,5 @@ export const VERSIONED_MANIFEST_SCHEMAS = {
   "0.1": ManifestSchemaV0_1,
   "0.2": ManifestSchemaV0_2,
   "0.3": ManifestSchemaV0_3,
+  "0.4": ManifestSchemaV0_4,
 } as const;