diff --git a/packages/cli/src/ui/AppContainer.tsx b/packages/cli/src/ui/AppContainer.tsx
index 23e7ca073e..968d61109d 100644
--- a/packages/cli/src/ui/AppContainer.tsx
+++ b/packages/cli/src/ui/AppContainer.tsx
@@ -1384,12 +1384,19 @@ Logging in with Google... Restarting Gemini CLI to continue.
 
       if (config) {
         if (parsedCommand.extensionContext) {
+          // Explicit extension invocation sets the "sticky" context to that extension,
+          // allowing subsequent multi-turn conversational replies (e.g. "yes, do that")
+          // to continue interacting with the extension's isolated plan directory.
           if (config.hasExtensionPlanDir(parsedCommand.extensionContext)) {
             config.setActiveExtensionContext(parsedCommand.extensionContext);
           } else {
+            // Extension doesn't have a plan dir registered, so fallback to default workspace context
             config.setActiveExtensionContext(undefined);
           }
         } else if (parsedCommand.commandToExecute?.name === 'plan') {
+          // If the user explicitly runs the native global /plan command (e.g., "/plan copy"),
+          // they are signaling an intent to manage their standard workspace plans,
+          // so we clear the sticky extension context to avoid misdirecting the operation.
           config.setActiveExtensionContext(undefined);
         }
       }
diff --git a/packages/core/src/tools/enter-plan-mode.test.ts b/packages/core/src/tools/enter-plan-mode.test.ts
index 8d44f313d3..a0a5676aa9 100644
--- a/packages/core/src/tools/enter-plan-mode.test.ts
+++ b/packages/core/src/tools/enter-plan-mode.test.ts
@@ -131,6 +131,17 @@ describe('EnterPlanModeTool', () => {
       expect(result.returnDisplay).toBe('Switching to Plan mode');
     });
 
+    it('should call getPlansDir immediately after setting ApprovalMode.PLAN to ensure JIT directory creation', async () => {
+      const invocation = tool.build({});
+
+      await invocation.execute({ abortSignal: new AbortController().signal });
+
+      expect(mockConfig.setApprovalMode).toHaveBeenCalledWith(
+        ApprovalMode.PLAN,
+      );
+      expect(mockConfig.getPlansDir).toHaveBeenCalled();
+    });
+
     it('should include optional reason in output display but not in llmContent', async () => {
       const reason = 'Design new database schema';
       const invocation = tool.build({ reason });
diff --git a/packages/core/src/tools/enter-plan-mode.ts b/packages/core/src/tools/enter-plan-mode.ts
index ca5ef465a9..9c43eb2b47 100644
--- a/packages/core/src/tools/enter-plan-mode.ts
+++ b/packages/core/src/tools/enter-plan-mode.ts
@@ -19,6 +19,7 @@ import { ENTER_PLAN_MODE_TOOL_NAME } from './tool-names.js';
 import { ApprovalMode } from '../policy/types.js';
 import { ENTER_PLAN_MODE_DEFINITION } from './definitions/coreTools.js';
 import { resolveToolDeclaration } from './definitions/resolver.js';
+import { debugLogger } from '../utils/debugLogger.js';
 
 export interface EnterPlanModeParams {
   reason?: string;
@@ -123,6 +124,18 @@ export class EnterPlanModeInvocation extends BaseToolInvocation<
 
     this.config.setApprovalMode(ApprovalMode.PLAN);
 
+    // Trigger JIT provisioning immediately. In sandboxed environments,
+    // the plans directory must exist on the host before it can be bound/allowed.
+    try {
+      this.config.getPlansDir();
+    } catch (e) {
+      // Log error but don't fail; write_file will try again later if possible
+      debugLogger.error(
+        'Failed to create plans directory during initialization.',
+        e,
+      );
+    }
+
     return {
       llmContent: 'Switching to Plan mode.',
       returnDisplay: this.params.reason