address feedback and make no permanent

packages/core/src/config/config.test.ts

@@ -3117,3 +3117,42 @@ describe('Model Persistence Bug Fix (#19864)', () => {
     expect(config.getModel()).toBe(PREVIEW_GEMINI_3_1_MODEL);
   });
 });
+
+describe('isClearContextOnPlanApprovalEnabled', () => {
+  const baseParams: ConfigParameters = {
+    sessionId: 'test',
+    targetDir: '.',
+    debugMode: false,
+    model: 'test-model',
+    cwd: '.',
+  };
+
+  it('should return false by default when no setting or override is present', () => {
+    const config = new Config(baseParams);
+    expect(config.isClearContextOnPlanApprovalEnabled()).toBe(false);
+  });
+
+  it('should return true when a session override is set to true', () => {
+    const config = new Config(baseParams);
+    config.setClearContextOnPlanApprovalSessionOverride(true);
+    expect(config.isClearContextOnPlanApprovalEnabled()).toBe(true);
+  });
+
+  it('should return false when a session override is set to false', () => {
+    const config = new Config(baseParams);
+    config.setClearContextOnPlanApprovalSessionOverride(false);
+    expect(config.isClearContextOnPlanApprovalEnabled()).toBe(false);
+  });
+
+  it('should prefer session override over persistent setting', () => {
+    const config = new Config({
+      ...baseParams,
+      planSettings: {
+        clearContextOnApproval: true,
+      },
+    } as unknown as ConfigParameters);
+    expect(config.isClearContextOnPlanApprovalEnabled()).toBe(true);
+    config.setClearContextOnPlanApprovalSessionOverride(false);
+    expect(config.isClearContextOnPlanApprovalEnabled()).toBe(false);
+  });
+});

packages/core/src/config/config.ts

@@ -2487,7 +2487,7 @@ export class Config implements McpContext {
   }
 
   isClearContextOnPlanApprovalEnabled(): boolean {
-    return this.getClearContextOnPlanApproval() ?? true;
+    return this.getClearContextOnPlanApproval() ?? false;
   }
 
   setClearContextOnPlanApprovalSessionOverride(value: boolean): void {

packages/core/src/tools/exit-plan-mode.ts

@@ -220,13 +220,28 @@ export class ExitPlanModeInvocation extends BaseToolInvocation<
           const history = geminiClient.getHistory();
           const startIndex = this.config.getPlanModeHistoryStartIndex();
 
-          // Find the first user message at or after the start index.
-          // This represents the beginning of the current planning phase.
+          // Find the user message that initiated the plan mode.
           let planningUserIndex = -1;
-          for (let i = startIndex; i < history.length - 1; i++) {
-            if (history[i].role === 'user') {
-              planningUserIndex = i;
-              break;
+
+          // If the message exactly at startIndex is a user message, then plan mode
+          // was initiated via a UI/CLI command before the message was added to history.
+          if (
+            startIndex < history.length &&
+            history[startIndex].role === 'user'
+          ) {
+            planningUserIndex = startIndex;
+          } else {
+            // Otherwise, Plan mode was initiated via the `enter_plan_mode` tool.
+            // The initiating user message is the last user message before startIndex.
+            for (
+              let i = Math.min(startIndex, history.length - 1);
+              i >= 0;
+              i--
+            ) {
+              if (history[i].role === 'user') {
+                planningUserIndex = i;
+                break;
+              }
             }
           }