diff --git a/packages/cli/src/utils/sandbox.test.ts b/packages/cli/src/utils/sandbox.test.ts
index 75128457bb..cfb9e21787 100644
--- a/packages/cli/src/utils/sandbox.test.ts
+++ b/packages/cli/src/utils/sandbox.test.ts
@@ -122,6 +122,9 @@ describe('sandbox', () => {
   });
 
   afterEach(() => {
+    // Note: We intentionally avoid vi.restoreAllMocks() here because it clears the top-level
+    // vi.mock('@google/gemini-cli-core') entirely, making its un-exported constants (like GEMINI_DIR)
+    // undefined in subsequent tests. Call counts are still reset by clearAllMocks() in beforeEach.
     process.env = originalEnv;
     process.argv = originalArgv;
   });
diff --git a/packages/core/src/utils/constants.ts b/packages/core/src/utils/constants.ts
index 5806dc8443..0a725cc3e4 100644
--- a/packages/core/src/utils/constants.ts
+++ b/packages/core/src/utils/constants.ts
@@ -10,3 +10,4 @@ export const REFERENCE_CONTENT_END = '--- End of content ---';
 export const LOCAL_DEV_SANDBOX_IMAGE_NAME = 'gemini-cli-sandbox';
 export const SANDBOX_NETWORK_NAME = 'gemini-cli-sandbox';
 export const SANDBOX_PROXY_NAME = 'gemini-cli-sandbox-proxy';
+export const GEMINI_DIR = '.gemini';