3 files changed, 43 insertions, 6 deletions
diff --git a/packages/cli/src/utils/package.ts b/packages/cli/src/utils/package.ts
new file mode 100644
index 00000000..d53a0234
--- /dev/null
+++ b/packages/cli/src/utils/package.ts
@@ -0,0 +1,38 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  readPackageUp,
+  type PackageJson as BasePackageJson,
+} from 'read-package-up';
+import { fileURLToPath } from 'url';
+import path from 'path';
+
+export type PackageJson = BasePackageJson & {
+  config?: {
+    sandboxImageUri?: string;
+  };
+};
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+let packageJson: PackageJson | undefined;
+
+export async function getPackageJson(): Promise<PackageJson | undefined> {
+  if (packageJson) {
+    return packageJson;
+  }
+
+  const result = await readPackageUp({ cwd: __dirname });
+  if (!result) {
+    // TODO: Maybe bubble this up as an error.
+    return;
+  }
+
+  packageJson = result.packageJson;
+  return packageJson;
+}
diff --git a/packages/cli/src/utils/sandbox.ts b/packages/cli/src/utils/sandbox.ts
index 74e45136..12fb6629 100644
--- a/packages/cli/src/utils/sandbox.ts
+++ b/packages/cli/src/utils/sandbox.ts
@@ -10,7 +10,7 @@ import path from 'node:path';
 import fs from 'node:fs';
 import { readFile } from 'node:fs/promises';
 import { quote } from 'shell-quote';
-import { readPackageUp } from 'read-package-up';
+import { getPackageJson } from './package.js';
 import commandExists from 'command-exists';
 import {
   USER_SETTINGS_DIR,
@@ -102,13 +102,10 @@ async function shouldUseCurrentUserInSandbox(): Promise<boolean> {
 async function getSandboxImageName(
   isCustomProjectSandbox: boolean,
 ): Promise<string> {
-  const packageJsonResult = await readPackageUp();
-  const packageJsonConfig = packageJsonResult?.packageJson.config as
-    | { sandboxImageUri?: string }
-    | undefined;
+  const packageJson = await getPackageJson();
   return (
     process.env.GEMINI_SANDBOX_IMAGE ??
-    packageJsonConfig?.sandboxImageUri ??
+    packageJson?.config?.sandboxImageUri ??
     (isCustomProjectSandbox
       ? LOCAL_DEV_SANDBOX_IMAGE_NAME + '-' + path.basename(path.resolve())
       : LOCAL_DEV_SANDBOX_IMAGE_NAME)
diff --git a/packages/core/package.json b/packages/core/package.json
index c216905b..511167ec 100644
--- a/packages/core/package.json
+++ b/packages/core/package.json
@@ -35,6 +35,7 @@
     "glob": "^10.4.5",
     "google-auth-library": "^9.11.0",
     "ignore": "^7.0.0",
+    "micromatch": "^4.0.8",
     "open": "^10.1.2",
     "shell-quote": "^1.8.2",
     "simple-git": "^3.28.0",
@@ -45,6 +46,7 @@
   "devDependencies": {
     "@types/diff": "^7.0.2",
     "@types/dotenv": "^6.1.1",
+    "@types/micromatch": "^4.0.8",
     "@types/minimatch": "^5.1.2",
     "@types/ws": "^8.5.10",
     "typescript": "^5.3.3",