fix: remove 400 errors from model history

packages/core/src/core/geminiChat.test.ts

@@ -1279,13 +1279,10 @@ describe('GeminiChat', () => {
       expect(mockLogContentRetry).toHaveBeenCalledTimes(1);
       expect(mockLogContentRetryFailure).toHaveBeenCalledTimes(1);
 
-      // History should still contain the user message.
+      // History should NOT contain the failed user message,
+      // to prevent invalid content from breaking subsequent requests.
       const history = chat.getHistory();
-      expect(history.length).toBe(1);
+      expect(history.length).toBe(0);
-      expect(history[0]).toEqual({
-        role: 'user',
-        parts: [{ text: 'test' }],
-      });
     });
 
     describe('API error retry behavior', () => {

packages/core/src/core/geminiChat.ts

@@ -380,6 +380,8 @@ export class GeminiChat {
             }
 
             if (isConnectionPhase) {
+              // Remove failed user content so it doesn't break subsequent requests
+              this.history.pop();
               throw error;
             }
             lastError = error;
@@ -429,6 +431,8 @@ export class GeminiChat {
               new ContentRetryFailureEvent(maxAttempts, lastError.type, model),
             );
           }
+          // Remove failed user content so it doesn't break subsequent requests
+          this.history.pop();
           throw lastError;
         }
       } finally {