fix(cli): improve network handling and shell escaping

- Add network connectivity check before CLIProxy operations

- Enhance PowerShell argument escaping for special characters

src/cliproxy/cliproxy-executor.ts

@@ -286,6 +286,29 @@ export async function execClaudeWithCLIProxy(
       spinner.succeed('CLIProxy binary ready');
     } catch (error) {
       spinner.fail('Failed to prepare CLIProxy');
+      const err = error as Error;
+
+      // Check if network offline (DNS, connection, or timeout failure)
+      const networkErrors = [
+        'getaddrinfo',
+        'ENOTFOUND',
+        'ETIMEDOUT',
+        'ECONNREFUSED',
+        'ENETUNREACH',
+        'EAI_AGAIN',
+      ];
+      const isNetworkError = networkErrors.some((errCode) => err.message.includes(errCode));
+
+      if (isNetworkError) {
+        console.error('');
+        console.error(fail('No network connection detected'));
+        console.error('');
+        console.error('CLIProxy binary download requires internet access.');
+        console.error('Please check your network connection and try again.');
+        console.error('');
+        process.exit(1);
+      }
+
       throw error;
     }
   }

src/utils/shell-executor.ts

@@ -11,9 +11,33 @@ import { getImageReadBlockHookEnv } from './hooks/image-read-block-hook-env';
 
 /**
  * Escape arguments for shell execution (Windows compatibility)
+ * Handles PowerShell special characters: backticks, $variables, double quotes
  */
 export function escapeShellArg(arg: string): string {
-  return '"' + String(arg).replace(/"/g, '""') + '"';
+  const isWindows = process.platform === 'win32';
+
+  if (isWindows) {
+    // PowerShell: Use single quotes for literal strings to prevent variable expansion
+    // Escape single quotes by doubling them (PowerShell syntax)
+    // Fallback to double quotes with escapes if single quotes present
+    if (arg.includes("'")) {
+      // Contains single quote - use double quotes with escape sequences
+      return (
+        '"' +
+        String(arg)
+          .replace(/\$/g, '`$') // Escape $ to prevent variable expansion
+          .replace(/`/g, '``') // Escape backticks
+          .replace(/"/g, '`"') + // Escape double quotes
+        '"'
+      );
+    } else {
+      // No single quotes - use single quotes for literal string (safest)
+      return "'" + String(arg) + "'";
+    }
+  } else {
+    // Unix/macOS: Double quotes with escaped inner quotes
+    return '"' + String(arg).replace(/"/g, '""') + '"';
+  }
 }
 
 /**