fix: use text/html;profile=mcp-app MIME type for MCP Apps resources (#577)

The ext-apps spec requires RESOURCE_MIME_TYPE (text/html;profile=mcp-app)
for hosts to recognize resources as MCP Apps. Without the profile parameter,
Claude Desktop/web fails with "Failed to load MCP App: the resource may
exceed the 5 MB size limit."

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -283,8 +283,8 @@ jobs:
       - name: Install dependencies
         run: npm ci
       
-      - name: Build project
+      - name: Build project (server + UI apps)
-        run: npm run build
+        run: npm run build:all
 
       # Database is already built and committed during development
       # Rebuilding here causes segfault due to memory pressure (exit code 139)
@@ -322,8 +322,8 @@ jobs:
       - name: Install dependencies
         run: npm ci
       
-      - name: Build project
+      - name: Build project (server + UI apps)
-        run: npm run build
+        run: npm run build:all
 
       # Database is already built and committed during development
       - name: Verify database exists
@@ -347,6 +347,8 @@ jobs:
           # Copy necessary files
           cp -r dist $PUBLISH_DIR/
           cp -r data $PUBLISH_DIR/
+          mkdir -p $PUBLISH_DIR/ui-apps
+          cp -r ui-apps/dist $PUBLISH_DIR/ui-apps/
           cp README.md $PUBLISH_DIR/
           cp LICENSE $PUBLISH_DIR/
           cp .env.example $PUBLISH_DIR/
@@ -377,7 +379,7 @@ jobs:
           pkg.license = 'MIT';
           pkg.bugs = { url: 'https://github.com/czlonkowski/n8n-mcp/issues' };
           pkg.homepage = 'https://github.com/czlonkowski/n8n-mcp#readme';
-          pkg.files = ['dist/**/*', 'data/nodes.db', '.env.example', 'README.md', 'LICENSE'];
+          pkg.files = ['dist/**/*', 'ui-apps/dist/**/*', 'data/nodes.db', '.env.example', 'README.md', 'LICENSE'];
           delete pkg.private;
           require('fs').writeFileSync('./package.json', JSON.stringify(pkg, null, 2));
           "

CHANGELOG.md

@@ -7,6 +7,25 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.34.3] - 2026-02-07
+
+### Fixed
+
+- **MCP Apps: Use correct MIME type for ext-apps spec**: Changed resource MIME type from `text/html` to `text/html;profile=mcp-app` (the `RESOURCE_MIME_TYPE` constant from `@modelcontextprotocol/ext-apps`). Without this profile parameter, Claude Desktop/web fails to recognize resources as MCP Apps and shows "Failed to load MCP App: the resource may exceed the 5 MB size limit."
+
+Conceived by Romuald Czlonkowski - https://www.aiadvisors.pl/en
+
+## [2.34.2] - 2026-02-07
+
+### Fixed
+
+- **CI: UI apps missing from npm package**: Release pipeline only ran `npm run build` (TypeScript), so `ui-apps/dist/` was never built and excluded from published packages
+  - Changed build step to `npm run build:all` in `build-and-verify` and `publish-npm` jobs
+  - Added `ui-apps/dist/` to npm publish staging directory
+  - Added `ui-apps/dist/**/*` to published package files list
+
+Conceived by Romuald Czlonkowski - https://www.aiadvisors.pl/en
+
 ## [2.34.1] - 2026-02-07
 
 ### Changed

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.34.1",
+  "version": "2.34.3",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

src/mcp/ui/app-configs.ts

@@ -6,7 +6,7 @@ export const UI_APP_CONFIGS: UIAppConfig[] = [
     displayName: 'Operation Result',
     description: 'Visual summary of workflow operations (create, update, delete, test)',
     uri: 'ui://n8n-mcp/operation-result',
-    mimeType: 'text/html',
+    mimeType: 'text/html;profile=mcp-app',
     toolPatterns: [
       'n8n_create_workflow',
       'n8n_update_full_workflow',
@@ -22,7 +22,7 @@ export const UI_APP_CONFIGS: UIAppConfig[] = [
     displayName: 'Validation Summary',
     description: 'Visual summary of node and workflow validation results',
     uri: 'ui://n8n-mcp/validation-summary',
-    mimeType: 'text/html',
+    mimeType: 'text/html;profile=mcp-app',
     toolPatterns: [
       'validate_node',
       'validate_workflow',

tests/unit/mcp/ui/app-configs.test.ts

@@ -65,9 +65,9 @@ describe('UI_APP_CONFIGS', () => {
     }
   });
 
-  it('should have consistent mimeType of text/html', () => {
+  it('should have consistent mimeType of text/html;profile=mcp-app', () => {
     for (const config of UI_APP_CONFIGS) {
-      expect(config.mimeType).toBe('text/html');
+      expect(config.mimeType).toBe('text/html;profile=mcp-app');
     }
   });