feat: make generated Zod schemas version-agnostic (v3.25+/v4)

- Change generated schema imports from `zod/v4` to standard `zod`
- Replace v4-only `z.looseObject()` with `z.object().passthrough()`
- Works with both Zod v3.25+ and v4, matching MCP TS SDK approach
- Bump version to 0.2.2

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: ochafik

package.json

@@ -5,7 +5,7 @@
     "url": "https://github.com/modelcontextprotocol/ext-apps"
   },
   "homepage": "https://github.com/modelcontextprotocol/ext-apps",
-  "version": "0.2.0",
+  "version": "0.2.2",
   "license": "MIT",
   "description": "MCP Apps SDK — Enable MCP servers to display interactive user interfaces in conversational clients.",
   "type": "module",

scripts/generate-schemas.ts

@@ -8,12 +8,10 @@
  *
  * ts-to-zod is a powerful tool but has limitations that require post-processing:
  *
- * ### 1. Zod Import Path (`"zod"` → `"zod/v4"`)
+ * ### 1. Zod Import Path (keep standard `"zod"` for version agnosticism)
  *
- * **Problem**: ts-to-zod generates `import { z } from "zod"` but this project
- * uses the Zod v4 subpath import `"zod/v4"` for explicit version targeting.
- *
- * **Solution**: Replace the import path in the generated output.
+ * ts-to-zod generates `import { z } from "zod"` which works with both
+ * Zod v3.25+ and v4. We keep this standard import to support both versions.
  *
  * ### 2. External Type References (`z.any()` → actual schemas)
  *
@@ -24,13 +22,14 @@
  *
  * **Solution**: Import the schemas from MCP SDK and remove the z.any() placeholders.
  *
- * ### 3. Index Signatures (`z.record().and()` → `z.looseObject()`)
+ * ### 3. Index Signatures (`z.record().and()` → `z.object().passthrough()`)
  *
  * **Problem**: TypeScript index signatures like `[key: string]: unknown` are
  * translated by ts-to-zod to `z.record(z.string(), z.unknown()).and(z.object({...}))`.
  * This creates a `ZodIntersection` type which doesn't support `.extend()` etc.
  *
- * **Solution**: Replace the intersection pattern with `z.looseObject()`.
+ * **Solution**: Replace with `z.object({...}).passthrough()` which works in both
+ * Zod v3 and v4, allowing extra properties while validating known ones.
  *
  * ## Adding Schema Descriptions
  *
@@ -178,50 +177,46 @@ async function generateJsonSchema() {
  * Post-process generated schemas for project compatibility.
  */
 function postProcess(content: string): string {
-  // 1. Update import to use zod/v4
-  content = content.replace(
-    'import { z } from "zod";',
-    'import * as z from "zod/v4";',
-  );
-
-  // 2. Add MCP SDK schema imports
+  // 1. Add MCP SDK schema imports (keep standard zod import for v3/v4 compatibility)
   const mcpImports = EXTERNAL_TYPE_SCHEMAS.join(",\n  ");
   content = content.replace(
-    'import * as z from "zod/v4";',
-    `import * as z from "zod/v4";
+    'import { z } from "zod";',
+    `import { z } from "zod";
 import {
   ${mcpImports},
 } from "@modelcontextprotocol/sdk/types.js";`,
   );
 
-  // 3. Remove z.any() placeholders for external types (now imported from MCP SDK)
+  // 2. Remove z.any() placeholders for external types (now imported from MCP SDK)
   for (const schema of EXTERNAL_TYPE_SCHEMAS) {
     content = content.replace(
       new RegExp(`(?:export )?const ${schema} = z\\.any\\(\\);\\n?`, "g"),
       "",
     );
   }
 
-  // 4. Replace z.record().and(z.object({...})) with z.looseObject({...})
+  // 3. Replace z.record().and(z.object({...})) with z.object({...}).passthrough()
   // Uses brace-counting to handle nested objects correctly.
-  content = replaceRecordAndWithLooseObject(content);
+  // passthrough() works in both Zod v3 and v4, unlike looseObject() which is v4-only.
+  content = replaceRecordAndWithPassthrough(content);
 
-  // 5. Add header comment
+  // 4. Add header comment
   content = content.replace(
     "// Generated by ts-to-zod",
     `// Generated by ts-to-zod
-// Post-processed for Zod v4 and MCP SDK compatibility
+// Post-processed for Zod v3/v4 compatibility and MCP SDK integration
 // Run: npm run generate:schemas`,
   );
 
   return content;
 }
 
 /**
- * Replace z.record(z.string(), z.unknown()).and(z.object({...})) with z.looseObject({...})
+ * Replace z.record(z.string(), z.unknown()).and(z.object({...})) with z.object({...}).passthrough()
  * Uses brace-counting to handle nested objects correctly.
+ * passthrough() works in both Zod v3 and v4, allowing extra properties.
  */
-function replaceRecordAndWithLooseObject(content: string): string {
+function replaceRecordAndWithPassthrough(content: string): string {
   const pattern = "z.record(z.string(), z.unknown()).and(z.object({";
   let result = content;
   let startIndex = 0;
@@ -245,7 +240,7 @@ function replaceRecordAndWithLooseObject(content: string): string {
     // Check if followed by ))
     if (result.slice(i, i + 2) === "))") {
       const objectContent = result.slice(objectStart, i - 1);
-      const replacement = `z.looseObject({${objectContent}})`;
+      const replacement = `z.object({${objectContent}}).passthrough()`;
       result = result.slice(0, matchStart) + replacement + result.slice(i + 2);
       startIndex = matchStart + replacement.length;
     } else {
@@ -260,11 +255,7 @@ function replaceRecordAndWithLooseObject(content: string): string {
  * Post-process generated integration tests.
  */
 function postProcessTests(content: string): string {
-  content = content.replace(
-    'import { z } from "zod";',
-    'import * as z from "zod/v4";',
-  );
-
+  // Keep standard zod import for v3/v4 compatibility
   content = content.replace(
     "// Generated by ts-to-zod",
     `// Generated by ts-to-zod