fix deep links not working in markdown

ui/desktop/src/components/MCPUIResourceRenderer.tsx

@@ -13,6 +13,7 @@ import { toast } from 'react-toastify';
 import { EmbeddedResource } from '../api';
 import { useTheme } from '../contexts/ThemeContext';
 import { errorMessage } from '../utils/conversionUtils';
+import { isProtocolSafe, getProtocol } from '../utils/urlSecurity';
 
 interface MCPUIResourceRendererProps {
   content: EmbeddedResource & { type: 'resource' };
@@ -177,52 +178,63 @@ export default function MCPUIResourceRenderer({
       const { url } = actionEvent.payload;
 
       try {
-        const urlObj = new URL(url);
-        if (!['http:', 'https:'].includes(urlObj.protocol)) {
+        // Safe protocols open directly, unknown protocols require user confirmation
+        // Dangerous protocols are blocked by main.ts in the open-external handler
+        if (isProtocolSafe(url)) {
+          await window.electron.openExternal(url);
           return {
-            status: 'error' as const,
-            error: {
-              code: UIActionErrorCode.NAVIGATION_FAILED,
-              message: `Blocked potentially unsafe URL protocol: ${urlObj.protocol}`,
-              details: { url, protocol: urlObj.protocol },
-            },
+            status: 'success' as const,
+            message: `Opened ${url} in default application`,
           };
         }
 
-        await window.electron.openExternal(url);
-        return {
-          status: 'success' as const,
-          message: `Opened ${url} in default browser`,
-        };
-      } catch (error) {
-        if (error instanceof TypeError && error.message.includes('Invalid URL')) {
+        // Unknown protocols require user confirmation
+        const protocol = getProtocol(url);
+        if (!protocol) {
           return {
             status: 'error' as const,
             error: {
               code: UIActionErrorCode.INVALID_PARAMS,
               message: `Invalid URL format: ${url}`,
-              details: { url, error: error.message },
+              details: { url },
             },
           };
-        } else if (error instanceof Error && error.message.includes('Failed to open')) {
-          return {
-            status: 'error' as const,
-            error: {
-              code: UIActionErrorCode.NAVIGATION_FAILED,
-              message: `Failed to open URL in default browser`,
-              details: { url, error: error.message },
-            },
-          };
-        } else {
+        }
+
+        const result = await window.electron.showMessageBox({
+          type: 'question',
+          buttons: ['Cancel', 'Open'],
+          defaultId: 0,
+          title: 'Open External Link',
+          message: `Open ${protocol} link?`,
+          detail: `This will open: ${url}`,
+        });
+
+        if (result.response !== 1) {
           return {
             status: 'error' as const,
             error: {
               code: UIActionErrorCode.NAVIGATION_FAILED,
-              message: `Unexpected error opening URL: ${url}`,
-              details: errorMessage(error),
+              message: 'User cancelled',
+              details: { url },
             },
           };
         }
+
+        await window.electron.openExternal(url);
+        return {
+          status: 'success' as const,
+          message: `Opened ${url} in default application`,
+        };
+      } catch (error) {
+        return {
+          status: 'error' as const,
+          error: {
+            code: UIActionErrorCode.NAVIGATION_FAILED,
+            message: `Failed to open URL: ${url}`,
+            details: errorMessage(error),
+          },
+        };
       }
     };
 

ui/desktop/src/components/MarkdownContent.tsx

@@ -28,6 +28,7 @@ const customOneDarkTheme = {
 
 import { Check, Copy } from './icons';
 import { wrapHTMLInCodeBlock } from '../utils/htmlSecurity';
+import { isProtocolSafe, getProtocol, BLOCKED_PROTOCOLS } from '../utils/urlSecurity';
 
 interface CodeProps extends React.ClassAttributes<HTMLElement>, React.HTMLAttributes<HTMLElement> {
   inline?: boolean;
@@ -143,6 +144,21 @@ const MarkdownCode = memo(
   })
 );
 
+// Custom URL transform to preserve deep link URLs (spotify:, vscode:, slack:, etc.)
+// React-markdown's default only allows http/https/mailto and strips all other protocols
+// We allow all protocols except dangerous ones (javascript:, data:, file:, etc.)
+const customUrlTransform = (url: string): string => {
+  try {
+    const protocol = new URL(url).protocol;
+    if (BLOCKED_PROTOCOLS.includes(protocol)) {
+      return '';
+    }
+  } catch {
+    // Not a valid URL, allow it (could be relative path)
+  }
+  return url;
+};
+
 const MarkdownContent = memo(function MarkdownContent({
   content,
   className = '',
@@ -179,6 +195,7 @@ const MarkdownContent = memo(function MarkdownContent({
       prose-li:m-0 prose-li:font-sans ${className}`}
     >
       <ReactMarkdown
+        urlTransform={customUrlTransform}
         remarkPlugins={[remarkGfm, remarkBreaks, [remarkMath, { singleDollarTextMath: false }]]}
         rehypePlugins={[
           [
@@ -191,7 +208,39 @@ const MarkdownContent = memo(function MarkdownContent({
           ],
         ]}
         components={{
-          a: ({ ...props }) => <a {...props} target="_blank" rel="noopener noreferrer" />,
+          a: (props) => {
+            return (
+              <a
+                {...props}
+                target="_blank"
+                rel="noopener noreferrer"
+                onClick={async (e) => {
+                  e.preventDefault();
+                  e.stopPropagation();
+                  if (!props.href) return;
+
+                  if (isProtocolSafe(props.href)) {
+                    window.electron.openExternal(props.href);
+                  } else {
+                    const protocol = getProtocol(props.href);
+                    if (!protocol) return;
+
+                    const result = await window.electron.showMessageBox({
+                      type: 'question',
+                      buttons: ['Cancel', 'Open'],
+                      defaultId: 0,
+                      title: 'Open External Link',
+                      message: `Open ${protocol} link?`,
+                      detail: `This will open: ${props.href}`,
+                    });
+                    if (result.response === 1) {
+                      window.electron.openExternal(props.href);
+                    }
+                  }
+                }}
+              />
+            );
+          },
           code: MarkdownCode,
         }}
       >

ui/desktop/src/components/McpApps/McpAppRenderer.tsx

@@ -22,6 +22,7 @@ import { cn } from '../../utils';
 import { DEFAULT_IFRAME_HEIGHT } from './utils';
 import { readResource, callTool } from '../../api';
 import { errorMessage } from '../../utils/conversionUtils';
+import { isProtocolSafe, getProtocol } from '../../utils/urlSecurity';
 
 interface McpAppRendererProps {
   resourceUri: string;
@@ -119,7 +120,37 @@ export default function McpAppRenderer({
       switch (method) {
         case 'ui/open-link': {
           const { url } = params as McpMethodParams['ui/open-link'];
-          await window.electron.openExternal(url);
+
+          // Safe protocols open directly, unknown protocols require confirmation
+          // Dangerous protocols are blocked by main.ts in the open-external handler
+          if (isProtocolSafe(url)) {
+            await window.electron.openExternal(url);
+          } else {
+            const protocol = getProtocol(url);
+            if (!protocol) {
+              return {
+                status: 'error',
+                message: 'Invalid URL',
+              } as McpMethodResponse['ui/open-link'];
+            }
+
+            const result = await window.electron.showMessageBox({
+              type: 'question',
+              buttons: ['Cancel', 'Open'],
+              defaultId: 0,
+              title: 'Open External Link',
+              message: `Open ${protocol} link?`,
+              detail: `This will open: ${url}`,
+            });
+            if (result.response !== 1) {
+              return {
+                status: 'error',
+                message: 'User cancelled',
+              } as McpMethodResponse['ui/open-link'];
+            }
+            await window.electron.openExternal(url);
+          }
+
           return {
             status: 'success',
             message: 'Link opened successfully',

ui/desktop/src/components/settings/app/ExternalBackendSection.tsx

@@ -4,6 +4,7 @@ import { Input } from '../../ui/input';
 import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '../../ui/card';
 import { AlertCircle } from 'lucide-react';
 import { ExternalGoosedConfig } from '../../../utils/settings';
+import { WEB_PROTOCOLS } from '../../../utils/urlSecurity';
 
 const DEFAULT_CONFIG: ExternalGoosedConfig = {
   enabled: false,
@@ -40,7 +41,7 @@ export default function ExternalBackendSection() {
     }
     try {
       const parsed = new URL(value);
-      if (!['http:', 'https:'].includes(parsed.protocol)) {
+      if (!WEB_PROTOCOLS.includes(parsed.protocol)) {
         setUrlError('URL must use http or https protocol');
         return false;
       }

ui/desktop/src/main.ts

@@ -46,6 +46,7 @@ import './utils/recipeHash';
 import { Client, createClient, createConfig } from './api/client';
 import { GooseApp } from './api';
 import installExtension, { REACT_DEVELOPER_TOOLS } from 'electron-devtools-installer';
+import { BLOCKED_PROTOCOLS, WEB_PROTOCOLS } from './utils/urlSecurity';
 
 function shouldSetupUpdater(): boolean {
   // Setup updater if either the flag is enabled OR dev updates are enabled
@@ -659,21 +660,34 @@ const createChat = async (
     }
   });
 
-  // Handle new window creation for links
+  // Handle new window creation for links (fallback for any links not handled by onClick)
   mainWindow.webContents.setWindowOpenHandler(({ url }) => {
-    // Open all links in external browser
-    if (url.startsWith('http:') || url.startsWith('https:')) {
-      shell.openExternal(url);
+    try {
+      const protocol = new URL(url).protocol;
+      if (BLOCKED_PROTOCOLS.includes(protocol)) {
+        return { action: 'deny' };
+      }
+    } catch {
       return { action: 'deny' };
     }
-    return { action: 'allow' };
+
+    shell.openExternal(url);
+    return { action: 'deny' };
   });
 
   // Handle new-window events (alternative approach for external links)
   // Use type assertion for non-standard Electron event
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   mainWindow.webContents.on('new-window' as any, function (event: any, url: string) {
     event.preventDefault();
+    try {
+      const protocol = new URL(url).protocol;
+      if (BLOCKED_PROTOCOLS.includes(protocol)) {
+        return;
+      }
+    } catch {
+      return;
+    }
     shell.openExternal(url);
   });
 
@@ -1166,15 +1180,15 @@ ipcMain.on('react-ready', (event) => {
   log.info('React ready - window is prepared for deep links');
 });
 
-// Handle external URL opening
 ipcMain.handle('open-external', async (_event, url: string) => {
-  try {
-    await shell.openExternal(url);
-    return true;
-  } catch (error) {
-    console.error('Error opening external URL:', error);
-    throw error;
+  const parsedUrl = new URL(url);
+
+  if (BLOCKED_PROTOCOLS.includes(parsedUrl.protocol)) {
+    console.warn(`[Main] Blocked dangerous protocol: ${parsedUrl.protocol}`);
+    return;
   }
+
+  await shell.openExternal(url);
 });
 
 ipcMain.handle('directory-chooser', async () => {
@@ -2150,8 +2164,8 @@ async function appMain() {
       // Validate URL
       const parsedUrl = new URL(url);
 
-      // Only allow http and https protocols
-      if (!['http:', 'https:'].includes(parsedUrl.protocol)) {
+      // Only allow http and https protocols for fetching web content
+      if (!WEB_PROTOCOLS.includes(parsedUrl.protocol)) {
         throw new Error('Invalid URL protocol. Only HTTP and HTTPS are allowed.');
       }
 
@@ -2189,8 +2203,8 @@ async function appMain() {
       // Validate URL
       const parsedUrl = new URL(url);
 
-      // Only allow http and https protocols
-      if (!['http:', 'https:'].includes(parsedUrl.protocol)) {
+      // Only allow http and https protocols for browser URLs
+      if (!WEB_PROTOCOLS.includes(parsedUrl.protocol)) {
         console.error('Invalid URL protocol. Only HTTP and HTTPS are allowed.');
         return;
       }