diff --git a/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.spec.ts b/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.spec.ts
index a90714c0417..17c8c0d33f2 100644
--- a/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.spec.ts
+++ b/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.spec.ts
@@ -21,6 +21,7 @@ import { TestBed } from "@angular/core/testing";
 import { JupyterPanelService } from "./jupyter-panel.service";
 import { WorkflowActionService } from "../workflow-graph/model/workflow-action.service";
 import { HttpClientTestingModule, HttpTestingController } from "@angular/common/http/testing";
+import { NotificationService } from "src/app/common/service/notification/notification.service";
 import { NotebookMigrationService } from "../notebook-migration/notebook-migration.service";
 import { GuiConfigService } from "src/app/common/service/gui-config.service";
 import { firstValueFrom, of } from "rxjs";
@@ -30,6 +31,7 @@ describe("JupyterPanelService", () => {
   let httpMock: HttpTestingController;
 
   let mockWorkflow: any;
+  let mockNotification: any;
   let mockNotebook: any;
   // Mutable so individual describe blocks can flip the flag mid-spec; the
   // service stores a reference, so mutations are observed on the next read.
@@ -55,6 +57,10 @@ describe("JupyterPanelService", () => {
       unhighlightLinks: vi.fn(),
     };
 
+    mockNotification = {
+      warning: vi.fn(),
+    };
+
     mockNotebook = {
       hasMapping: vi.fn().mockReturnValue(true),
       getMapping: vi.fn().mockReturnValue({
@@ -75,6 +81,7 @@ describe("JupyterPanelService", () => {
       providers: [
         JupyterPanelService,
         { provide: WorkflowActionService, useValue: mockWorkflow },
+        { provide: NotificationService, useValue: mockNotification },
         { provide: NotebookMigrationService, useValue: mockNotebook },
         { provide: GuiConfigService, useValue: mockGuiConfig },
       ],
@@ -88,6 +95,63 @@ describe("JupyterPanelService", () => {
     httpMock.verify();
   });
 
+  // Panel visibility
+  it("should open and close panel", () => {
+    let state: boolean | null = null;
+
+    service.jupyterNotebookPanelVisible$.subscribe(v => (state = v));
+
+    service.openPanel("JupyterNotebookPanel");
+    expect(state).toBe(true);
+
+    service.closeJupyterNotebookPanel();
+    expect(state).toBe(false);
+  });
+
+  it("should minimize panel", () => {
+    let state: boolean | null = true;
+
+    service.jupyterNotebookPanelVisible$.subscribe(v => (state = v));
+
+    service.minimizeJupyterNotebookPanel();
+
+    expect(state).toBe(false);
+  });
+
+  // openJupyterNotebookPanel
+  it("should warn if no mapping exists", () => {
+    mockNotebook.hasMapping.mockReturnValue(false);
+
+    service.openJupyterNotebookPanel();
+
+    expect(mockNotification.warning).toHaveBeenCalled();
+  });
+
+  it("should open panel if mapping exists", () => {
+    mockNotebook.hasMapping.mockReturnValue(true);
+
+    let state: boolean | null = false;
+
+    service.jupyterNotebookPanelVisible$.subscribe(v => (state = v));
+
+    service.openJupyterNotebookPanel();
+
+    expect(state).toBe(true);
+  });
+
+  // openPanel
+  it("should open panel only for correct name", () => {
+    let state: boolean | null = false;
+
+    service.jupyterNotebookPanelVisible$.subscribe(v => (state = v));
+
+    service.openPanel("WrongPanel");
+    expect(state).toBe(false);
+
+    service.openPanel("JupyterNotebookPanel");
+    expect(state).toBe(true);
+  });
+
   // HTTP fetchNotebookAndMapping
   it("should return 0 when exists=false", async () => {
     const resultPromise = firstValueFrom((service as any).fetchNotebookAndMapping(1, 1));
@@ -98,6 +162,23 @@ describe("JupyterPanelService", () => {
     expect(await resultPromise).toBe(0);
   });
 
+  // jupyterNotebookExists$ starts false and flips true once init()'s fetch finds
+  // a notebook for the workflow; the toolbar's expand button binds to this.
+  it("sets jupyterNotebookExists$ true after a workflow's notebook is fetched", async () => {
+    mockNotebook.sendNotebookToJupyter = vi.fn().mockResolvedValue(1);
+    const states: boolean[] = [];
+    service.jupyterNotebookExists$.subscribe(v => states.push(v));
+
+    service.init();
+    httpMock
+      .expectOne(r => r.url.includes("/notebook-migration/fetch-notebook-and-mapping"))
+      .flush({ exists: true, mapping: { cell_to_operator: {}, operator_to_cell: {} }, notebook: {} });
+    await new Promise(resolve => setTimeout(resolve, 0));
+
+    expect(states[0]).toBe(false); // starts false
+    expect(states.at(-1)).toBe(true); // true once the notebook is found
+  });
+
   // init(): subscribes to workflow changes, drops the stale mapping for the
   // current workflow, and fetches the incoming workflow's notebook + mapping.
   it("init subscribes, drops the stale mapping, and fetches for the new workflow", () => {
@@ -303,6 +384,36 @@ describe("JupyterPanelService", () => {
       expect(mockWorkflow.workflowMetaDataChanged).not.toHaveBeenCalled();
     });
 
+    it("openPanel does not flip the visibility stream", () => {
+      let state: boolean | null = false;
+      service.jupyterNotebookPanelVisible$.subscribe(v => (state = v));
+      service.openPanel("JupyterNotebookPanel");
+      expect(state).toBe(false);
+    });
+
+    it("closeJupyterNotebookPanel does not flip visibility or delete the mapping", () => {
+      // BehaviorSubject's initial value is false; the meaningful assertion is
+      // that the side effect (deleteMapping) was never called.
+      service.closeJupyterNotebookPanel();
+      expect(mockNotebook.deleteMapping).not.toHaveBeenCalled();
+    });
+
+    it("minimizeJupyterNotebookPanel does not flip visibility", () => {
+      const visibleSubject = (service as any).jupyterNotebookPanelVisible;
+      visibleSubject.next(true);
+      service.minimizeJupyterNotebookPanel();
+      expect(visibleSubject.value).toBe(true);
+    });
+
+    it("openJupyterNotebookPanel does not warn or flip visibility", () => {
+      mockNotebook.hasMapping.mockReturnValue(false);
+      let state: boolean | null = false;
+      service.jupyterNotebookPanelVisible$.subscribe(v => (state = v));
+      service.openJupyterNotebookPanel();
+      expect(state).toBe(false);
+      expect(mockNotification.warning).not.toHaveBeenCalled();
+    });
+
     it("onWorkflowComponentClick does not postMessage to the iframe", async () => {
       const mockIframe = {
         contentWindow: { postMessage: vi.fn() },
diff --git a/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.ts b/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.ts
index f2083e5c5d6..ceccff995a4 100644
--- a/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.ts
+++ b/frontend/src/app/workspace/service/jupyter-panel/jupyter-panel.service.ts
@@ -18,10 +18,11 @@
  */
 
 import { Injectable } from "@angular/core";
-import { catchError, map, of } from "rxjs";
+import { BehaviorSubject, catchError, map, of } from "rxjs";
 import { WorkflowActionService } from "../workflow-graph/model/workflow-action.service";
 import { OperatorLink } from "../../types/workflow-common.interface";
 import { HttpClient, HttpHeaders } from "@angular/common/http";
+import { NotificationService } from "src/app/common/service/notification/notification.service";
 import { distinctUntilChanged, switchMap } from "rxjs/operators";
 import { AppSettings } from "../../../common/app-setting";
 import { NotebookMigrationService } from "../notebook-migration/notebook-migration.service";
@@ -31,6 +32,16 @@ import { GuiConfigService } from "../../../common/service/gui-config.service";
   providedIn: "root",
 })
 export class JupyterPanelService {
+  private jupyterNotebookPanelVisible = new BehaviorSubject<boolean>(false);
+  public jupyterNotebookPanelVisible$ = this.jupyterNotebookPanelVisible.asObservable();
+
+  // Whether the current workflow has an associated notebook in the migration DB.
+  // Driven by the per-workflow fetch in init(): reset on every workflow change,
+  // set true only when a notebook/mapping is found. Used to gate the toolbar's
+  // expand button so it appears only for workflows that actually have a notebook.
+  private jupyterNotebookExists = new BehaviorSubject<boolean>(false);
+  public jupyterNotebookExists$ = this.jupyterNotebookExists.asObservable();
+
   private iframeRef: HTMLIFrameElement | null = null; // Store reference to iframe element
 
   // Precomputed dictionary for cell to highlight mapping
@@ -42,6 +53,7 @@ export class JupyterPanelService {
   constructor(
     private workflowActionService: WorkflowActionService,
     private http: HttpClient,
+    private notificationService: NotificationService,
     private notebookMigrationService: NotebookMigrationService,
     private config: GuiConfigService
   ) {
@@ -87,27 +99,21 @@ export class JupyterPanelService {
         distinctUntilChanged()
       )
       .subscribe(wid => {
-        // On every workflow change, drop the outgoing workflow's stale mapping
-        // and clear the highlight index. Clearing here (not only inside
-        // precomputeHighlightMapping, which runs only on a successful fetch)
-        // ensures switching to a workflow without a stored notebook can't leave
-        // the previous workflow's highlights active. This cleanup previously
-        // happened inside closeJupyterNotebookPanel; the panel-visibility
-        // surface lives with the iframe component in
-        // `migration-tool-jupyter-panel` now, so it is inlined.
-        const currentWid = this.workflowActionService.getWorkflow().wid;
-        if (currentWid !== undefined) {
-          this.notebookMigrationService.deleteMapping("mapping_wid_" + currentWid);
-        }
+        // On every workflow change, close the panel (which also drops the
+        // outgoing workflow's stale mapping) and clear the highlight index, so a
+        // switch to a workflow without a stored notebook can't leave the
+        // previous workflow's highlights active.
+        this.closeJupyterNotebookPanel();
         this.cellToHighlightMapping = {};
+        this.jupyterNotebookExists.next(false);
         // Skip unsaved workflows (wid undefined) and wid 0; both would POST
         // without a usable wid and 500 on the backend.
         if (wid) {
           this.fetchNotebookAndMapping(wid).subscribe(result => {
             if (result == 1) {
+              this.jupyterNotebookExists.next(true);
               this.precomputeHighlightMapping();
-              // Panel auto-open on workflow restore is wired in
-              // `migration-tool-jupyter-panel` once the visibility API exists.
+              this.openJupyterNotebookPanel();
             }
           });
         }
@@ -198,6 +204,45 @@ export class JupyterPanelService {
     this.iframeRef = iframe;
   }
 
+  // Open the Jupyter Notebook panel
+  public openPanel(panelName: string): void {
+    if (!this.enabled) return;
+    if (panelName === "JupyterNotebookPanel") {
+      this.jupyterNotebookPanelVisible.next(true);
+    }
+  }
+
+  // Close the Jupyter Notebook panel
+  public closeJupyterNotebookPanel(): void {
+    if (!this.enabled) return;
+    this.jupyterNotebookPanelVisible.next(false);
+    const wid = this.workflowActionService.getWorkflow().wid;
+    if (wid != undefined) {
+      this.notebookMigrationService.deleteMapping("mapping_wid_" + wid);
+    }
+  }
+
+  // Minimize the Jupyter Notebook panel
+  public minimizeJupyterNotebookPanel(): void {
+    if (!this.enabled) return;
+    this.jupyterNotebookPanelVisible.next(false);
+  }
+
+  // Expand the Jupyter Notebook panel
+  public openJupyterNotebookPanel(): void {
+    if (!this.enabled) return;
+    const wid = this.workflowActionService.getWorkflow().wid;
+    const mappingKey = "mapping_wid_" + wid;
+    // Check if there is corresponding mapping data
+    if (wid === undefined || !this.notebookMigrationService.hasMapping(mappingKey)) {
+      this.notificationService.warning("No Jupyter notebook associated with this workflow.");
+      return;
+    }
+
+    // Expand only if the mapping exists
+    this.jupyterNotebookPanelVisible.next(true);
+  }
+
   // Handle messages from the Jupyter notebook iframe
   private handleNotebookMessage = async (event: MessageEvent) => {
     if (!this.enabled) return;