fix(logging): Ensure sandbox startup messages are routed to stderr (#5725)

packages/cli/src/ui/types.ts

@@ -224,7 +224,7 @@ export type Message =
     };
 
 export interface ConsoleMessageItem {
-  type: 'log' | 'warn' | 'error' | 'debug';
+  type: 'log' | 'warn' | 'error' | 'debug' | 'info';
   content: string;
   count: number;
 }

packages/cli/src/ui/utils/ConsolePatcher.ts

@@ -18,6 +18,7 @@ export class ConsolePatcher {
   private originalConsoleWarn = console.warn;
   private originalConsoleError = console.error;
   private originalConsoleDebug = console.debug;
+  private originalConsoleInfo = console.info;
 
   private params: ConsolePatcherParams;
 
@@ -30,6 +31,7 @@ export class ConsolePatcher {
     console.warn = this.patchConsoleMethod('warn', this.originalConsoleWarn);
     console.error = this.patchConsoleMethod('error', this.originalConsoleError);
     console.debug = this.patchConsoleMethod('debug', this.originalConsoleDebug);
+    console.info = this.patchConsoleMethod('info', this.originalConsoleInfo);
   }
 
   cleanup = () => {
@@ -37,13 +39,14 @@ export class ConsolePatcher {
     console.warn = this.originalConsoleWarn;
     console.error = this.originalConsoleError;
     console.debug = this.originalConsoleDebug;
+    console.info = this.originalConsoleInfo;
   };
 
   private formatArgs = (args: unknown[]): string => util.format(...args);
 
   private patchConsoleMethod =
     (
-      type: 'log' | 'warn' | 'error' | 'debug',
+      type: 'log' | 'warn' | 'error' | 'debug' | 'info',
       originalMethod: (...args: unknown[]) => void,
     ) =>
     (...args: unknown[]) => {

packages/cli/src/utils/sandbox.ts

@@ -16,6 +16,7 @@ import {
 } from '../config/settings.js';
 import { promisify } from 'util';
 import { Config, SandboxConfig } from '@google/gemini-cli-core';
+import { ConsolePatcher } from '../ui/utils/ConsolePatcher.js';
 
 const execAsync = promisify(exec);
 
@@ -185,6 +186,13 @@ export async function start_sandbox(
   nodeArgs: string[] = [],
   cliConfig?: Config,
 ) {
+  const patcher = new ConsolePatcher({
+    debugMode: cliConfig?.getDebugMode() || !!process.env.DEBUG,
+    stderr: true,
+  });
+  patcher.patch();
+
+  try {
     if (config.command === 'sandbox-exec') {
       // disallow BUILD_SANDBOX
       if (process.env.BUILD_SANDBOX) {
@@ -424,7 +432,10 @@ export async function start_sandbox(
     if (!fs.existsSync(userSettingsDirOnHost)) {
       fs.mkdirSync(userSettingsDirOnHost);
     }
-  args.push('--volume', `${userSettingsDirOnHost}:${userSettingsDirInSandbox}`);
+    args.push(
+      '--volume',
+      `${userSettingsDirOnHost}:${userSettingsDirInSandbox}`,
+    );
     if (userSettingsDirInSandbox !== userSettingsDirOnHost) {
       args.push(
         '--volume',
@@ -784,6 +795,9 @@ export async function start_sandbox(
         resolve();
       });
     });
+  } finally {
+    patcher.cleanup();
+  }
 }
 
 // Helper functions to ensure sandbox image is present