fix: handle symlinks during extension installation

packages/core/src/extension/claude-converter.ts

@@ -387,15 +387,15 @@ export async function convertClaudePluginPackage(
   const strict = marketplacePlugin.strict ?? false;
   let mergedConfig: ClaudePluginConfig;
 
-  if (strict) {
-    const pluginJsonPath = path.join(
-      pluginSource,
-      '.claude-plugin',
-      'plugin.json',
-    );
-    if (!fs.existsSync(pluginJsonPath)) {
-      throw new Error(`Strict mode requires plugin.json at ${pluginJsonPath}`);
-    }
+  const pluginJsonPath = path.join(
+    pluginSource,
+    '.claude-plugin',
+    'plugin.json',
+  );
+  if (strict && !fs.existsSync(pluginJsonPath)) {
+    throw new Error(`Strict mode requires plugin.json at ${pluginJsonPath}`);
+  }
+  if (fs.existsSync(pluginJsonPath)) {
     const pluginContent = fs.readFileSync(pluginJsonPath, 'utf-8');
     const pluginConfig: ClaudePluginConfig = JSON.parse(pluginContent);
     mergedConfig = mergeClaudeConfigs(marketplacePlugin, pluginConfig);
@@ -552,6 +552,18 @@ async function collectResources(
         const srcFile = path.join(resolvedPath, file);
         const destFile = path.join(finalDestDir, file);
 
+        // Check if the source is a regular file (skip sockets, FIFOs, directories behind symlinks, etc.)
+        try {
+          const fileStat = fs.statSync(srcFile);
+          if (!fileStat.isFile()) {
+            debugLogger.debug(`Skipping non-regular file: ${srcFile}`);
+            continue;
+          }
+        } catch {
+          debugLogger.debug(`Failed to stat file, skipping: ${srcFile}`);
+          continue;
+        }
+
         // Ensure parent directory exists
         const destFileDir = path.dirname(destFile);
         if (!fs.existsSync(destFileDir)) {

packages/core/src/extension/extensionManager.ts

@@ -1238,7 +1238,21 @@ export async function copyExtension(
   source: string,
   destination: string,
 ): Promise<void> {
-  await fs.promises.cp(source, destination, { recursive: true });
+  await fs.promises.cp(source, destination, {
+    recursive: true,
+    dereference: true,
+    filter: async (src: string) => {
+      try {
+        const stats = await fs.promises.stat(src);
+        // Only copy regular files and directories
+        // Skip sockets, FIFOs, block devices, and character devices
+        return stats.isFile() || stats.isDirectory();
+      } catch {
+        // If we can't stat the file, skip it
+        return false;
+      }
+    },
+  });
 }
 
 export function getExtensionId(

packages/core/src/extension/gemini-converter.ts

@@ -130,9 +130,24 @@ export async function copyDirectory(
 
     if (entry.isDirectory()) {
       await copyDirectory(sourcePath, destPath);
-    } else {
+    } else if (entry.isSymbolicLink()) {
+      // Resolve symlink and copy the target content
+      try {
+        const realPath = fs.realpathSync(sourcePath);
+        const targetStat = fs.statSync(realPath);
+        if (targetStat.isDirectory()) {
+          await copyDirectory(realPath, destPath);
+        } else if (targetStat.isFile()) {
+          fs.copyFileSync(realPath, destPath);
+        }
+        // Skip sockets, FIFOs, etc.
+      } catch {
+        // Skip broken symlinks
+      }
+    } else if (entry.isFile()) {
       fs.copyFileSync(sourcePath, destPath);
     }
+    // Skip sockets, FIFOs, block devices, and character devices
   }
 }
 

packages/core/src/extension/github.test.ts

@@ -69,6 +69,8 @@ describe('git extension helpers', () => {
       await cloneFromGit(installMetadata, destination);
 
       expect(mockGit.clone).toHaveBeenCalledWith('http://my-repo.com', './', [
+        '-c',
+        'core.symlinks=true',
         '--depth',
         '1',
       ]);

packages/core/src/extension/github.ts

@@ -75,7 +75,12 @@ export async function cloneFromGit(
         // We let git handle the source as is.
       }
     }
-    await git.clone(sourceUrl, './', ['--depth', '1']);
+    await git.clone(sourceUrl, './', [
+      '-c',
+      'core.symlinks=true',
+      '--depth',
+      '1',
+    ]);
 
     const remotes = await git.getRemotes(true);
     if (remotes.length === 0) {