From a810ca80bcee1590fe8491e611a7dff4335a790e Mon Sep 17 00:00:00 2001
From: Sehoon Shon <sshon@google.com>
Date: Wed, 12 Nov 2025 19:30:43 -0500
Subject: [PATCH] Allow users to reset to auto when it's in fallback mode
 (#12623)

---
 packages/core/src/config/config.test.ts | 31 +++++++++++++++++++++++++
 packages/core/src/config/config.ts      |  5 ++--
 2 files changed, 33 insertions(+), 3 deletions(-)

diff --git a/packages/core/src/config/config.test.ts b/packages/core/src/config/config.test.ts
index 7e71e71cce..6cc77d3328 100644
--- a/packages/core/src/config/config.test.ts
+++ b/packages/core/src/config/config.test.ts
@@ -1509,6 +1509,37 @@ describe('Config getHooks', () => {
       expect(config.isInFallbackMode()).toBe(false);
       expect(mockCoreEvents.emitModelChanged).toHaveBeenCalledWith(proModel);
     });
+
+    it('should allow setting auto model from non-auto model and disable fallback mode', () => {
+      const config = new Config(baseParams);
+      config.setFallbackMode(true);
+      expect(config.isInFallbackMode()).toBe(true);
+
+      config.setModel('auto');
+
+      expect(config.getModel()).toBe('auto');
+      expect(config.isInFallbackMode()).toBe(false);
+      expect(mockCoreEvents.emitModelChanged).toHaveBeenCalledWith('auto');
+    });
+
+    it('should allow setting auto model from auto model if it is in the fallback mode', () => {
+      const config = new Config({
+        cwd: '/tmp',
+        targetDir: '/path/to/target',
+        debugMode: false,
+        sessionId: 'test-session-id',
+        model: 'auto',
+        usageStatisticsEnabled: false,
+      });
+      config.setFallbackMode(true);
+      expect(config.isInFallbackMode()).toBe(true);
+
+      config.setModel('auto');
+
+      expect(config.getModel()).toBe('auto');
+      expect(config.isInFallbackMode()).toBe(false);
+      expect(mockCoreEvents.emitModelChanged).toHaveBeenCalledWith('auto');
+    });
   });
 });
 
diff --git a/packages/core/src/config/config.ts b/packages/core/src/config/config.ts
index b72bf2d9ca..c4a94bcfc9 100644
--- a/packages/core/src/config/config.ts
+++ b/packages/core/src/config/config.ts
@@ -769,12 +769,11 @@ export class Config {
   }
 
   setModel(newModel: string): void {
-    this.setFallbackMode(false);
-
-    if (this.model !== newModel) {
+    if (this.model !== newModel || this.inFallbackMode) {
       this.model = newModel;
       coreEvents.emitModelChanged(newModel);
     }
+    this.setFallbackMode(false);
   }
 
   isInFallbackMode(): boolean {