diff --git a/packages/cli/src/commands/extensions/link.ts b/packages/cli/src/commands/extensions/link.ts
index d3eff0a6e..5baeee3f2 100644
--- a/packages/cli/src/commands/extensions/link.ts
+++ b/packages/cli/src/commands/extensions/link.ts
@@ -29,6 +29,10 @@ export async function handleLink(args: InstallArgs) {
       installMetadata,
       requestConsentOrFail.bind(null, requestConsentNonInteractive),
     );
+    if (!extension) {
+      console.log('Link extension failed to install.');
+      return;
+    }
     console.log(
       `Extension "${extension.name}" linked successfully and enabled.`,
     );
diff --git a/packages/cli/src/commands/extensions/list.ts b/packages/cli/src/commands/extensions/list.ts
index ea0fcba91..ef6545f20 100644
--- a/packages/cli/src/commands/extensions/list.ts
+++ b/packages/cli/src/commands/extensions/list.ts
@@ -13,7 +13,7 @@ export async function handleList() {
     const extensionManager = await getExtensionManager();
     const extensions = extensionManager.getLoadedExtensions();
 
-    if (extensions.length === 0) {
+    if (!extensions || extensions.length === 0) {
       console.log('No extensions installed.');
       return;
     }
diff --git a/packages/core/src/config/config.test.ts b/packages/core/src/config/config.test.ts
index f50a209f6..a6dfe135e 100644
--- a/packages/core/src/config/config.test.ts
+++ b/packages/core/src/config/config.test.ts
@@ -208,6 +208,7 @@ describe('Server Config (config.ts)', () => {
     telemetry: TELEMETRY_SETTINGS,
     model: MODEL,
     usageStatisticsEnabled: false,
+    overrideExtensions: [],
   };
 
   beforeEach(() => {