diff --git a/.changeset/use-planning-session-back.md b/.changeset/use-planning-session-back.md
new file mode 100644
index 0000000000..fc0ce749f7
--- /dev/null
+++ b/.changeset/use-planning-session-back.md
@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Replace the Planning Sessions toggle with a consistent Back-to-sessions control.
+category: fix
+dev: Uses the existing session-list transition across desktop and compact Planning layouts.
diff --git a/packages/dashboard/app/components/PlanningModeModal.css b/packages/dashboard/app/components/PlanningModeModal.css
index 9dd559b39a..45ae835216 100644
--- a/packages/dashboard/app/components/PlanningModeModal.css
+++ b/packages/dashboard/app/components/PlanningModeModal.css
@@ -587,11 +587,12 @@ The New session button must look EXACTLY like Missions' primary sidebar create b
   padding: 0 8px;
 }
 
-.planning-mobile-back {
-  /* Visible only on mobile (see media query below). On desktop the sidebar
-     is always visible alongside the detail pane, so a back button is never
-     needed. */
-  display: none;
+.planning-session-back {
+  display: inline-flex;
+  min-width: calc(var(--space-md) * 2.25);
+  min-height: calc(var(--space-md) * 2.25);
+  align-items: center;
+  justify-content: center;
   background: none;
   border: none;
   color: var(--text);
@@ -602,11 +603,11 @@ The New session button must look EXACTLY like Missions' primary sidebar create b
   transition: background var(--transition-fast), box-shadow var(--transition-fast);
 }
 
-.planning-mobile-back:hover {
+.planning-session-back:hover {
   background: var(--card-hover);
 }
 
-.planning-mobile-back:focus-visible {
+.planning-session-back:focus-visible {
   outline: none;
   box-shadow: var(--focus-ring-strong);
 }
@@ -711,14 +712,6 @@ The New session button must look EXACTLY like Missions' primary sidebar create b
   .planning-modal-body--show-list .planning-detail {
     display: none;
   }
-  /* The rendered Back control needs a full touch target and must not be squeezed out of the title row. */
-  .planning-mobile-back {
-    display: inline-flex;
-    min-width: calc(var(--space-md) * 2.25);
-    min-height: calc(var(--space-md) * 2.25);
-    align-items: center;
-    justify-content: center;
-  }
   /* Always keep action buttons visible on mobile (no hover) */
   .planning-sidebar-item-delete,
   .planning-sidebar-item-archive {
@@ -1830,14 +1823,6 @@ plan actions, and a token-sized bottom inset keep all three controls inline with
     display: none;
   }
 
-  .planning-mobile-back {
-    display: inline-flex;
-    min-width: calc(var(--space-md) * 2.25);
-    min-height: calc(var(--space-md) * 2.25);
-    align-items: center;
-    justify-content: center;
-  }
-
   .planning-summary-actions {
     flex-wrap: wrap;
     align-items: flex-start;
@@ -2169,7 +2154,7 @@ mobile and desktop offer the same View task / Return to sessions choices.
   /*
   FNXC:PlanningModeMobile 2026-07-20-21:50:
   The Planning detail header keeps Back, the lightbulb, a single-line truncated title, and Edit on
-  one row. Fixed icon controls may not shrink; only the title yields space before Sessions/History.
+  one row. Fixed icon controls may not shrink; only the title yields space before History.
   */
 
   .planning-modal--embedded .modal-header--embedded .detail-title-row {
@@ -2191,7 +2176,7 @@ mobile and desktop offer the same View task / Return to sessions choices.
 
   .planning-modal--embedded .modal-header--embedded .detail-title-row > svg,
   .planning-modal--embedded .modal-header--embedded .detail-title-row > .btn-icon,
-  .planning-modal--embedded .modal-header--embedded .planning-mobile-back {
+  .planning-modal--embedded .modal-header--embedded .planning-session-back {
     flex: 0 0 auto;
   }
 
@@ -2202,7 +2187,7 @@ mobile and desktop offer the same View task / Return to sessions choices.
 
   .planning-header-controls {
     display: grid;
-    grid-template-columns: repeat(2, minmax(0, 1fr));
+    grid-template-columns: minmax(0, 1fr);
     width: 100%;
   }
 
diff --git a/packages/dashboard/app/components/PlanningModeModal.tsx b/packages/dashboard/app/components/PlanningModeModal.tsx
index 3628a0d101..e0bf22507f 100644
--- a/packages/dashboard/app/components/PlanningModeModal.tsx
+++ b/packages/dashboard/app/components/PlanningModeModal.tsx
@@ -617,14 +617,13 @@ export function PlanningModeModal({ isOpen, onClose, onTaskCreated, onTasksCreat
   const isCompactInterview = viewportMode !== "desktop" || isShortViewport();
   /*
   FNXC:PlanningModeMobile 2026-07-20-10:30:
-  FN-8427 makes the saved-session list a real compact destination. Both Back and Sessions
-  enter this one mode, which must unmount the active interview plan so it cannot consume
-  flex height beneath session rows. Desktop preserves its three-pane interview until its
-  explicit Sessions toggle requests the same list destination.
+  FN-8427 makes the saved-session list a real destination. Back enters this mode and unmounts
+  the active interview plan so it cannot consume flex height beneath session rows.
   */
   const isSessionListMode = showSessionList || (isCompactInterview && !mobileShowDetail);
-  // FNXC:PlanningModeMobile 2026-07-20-10:30: Empty mobile state opens the composer because no saved destination exists; once sessions exist, every compact detail surface gets this single Back-to-list escape.
-  const canReturnToSessionList = isCompactInterview && mobileShowDetail && planningSessions.length > 0;
+  // FNXC:PlanningSessionBack 2026-07-21-11:15: Back covers selected details on every viewport and drafts whenever saved sessions exist; list mode removes it instead of leaving an orphaned control.
+  const canReturnToSessionList = !isSessionListMode
+    && (selectedSessionId !== null || planningSessions.length > 0);
   const [isRefineMenuOpen, setIsRefineMenuOpen] = useState(false);
   const [mobileWorkspaceTab, setMobileWorkspaceTab] = useState<"question" | "plan">("question");
   /*
@@ -1918,6 +1917,7 @@ export function PlanningModeModal({ isOpen, onClose, onTaskCreated, onTasksCreat
   }, [projectId, resetDetailState, resumeSessionId, selectedSessionId]);
 
   const handleBackToList = useCallback(() => {
+    setIsHistoryOpen(false);
     setShowSessionList(true);
     setMobileShowDetail(false);
   }, []);
@@ -2832,13 +2832,13 @@ export function PlanningModeModal({ isOpen, onClose, onTaskCreated, onTasksCreat
       <div className={isEmbedded ? "modal modal-lg planning-modal planning-modal--embedded" : "modal modal-lg planning-modal"} ref={modalRef}>
         {/*
         FNXC:PlanningMode 2026-06-22-00:00:
-        Embedded planning is a main-content destination, not a dialog: it drops the modal close button and renders a plain common title (modal-header--embedded) matching other embedded views like Command Center. The mobile back affordance stays because it navigates the session list, not the view.
+        Embedded planning is a main-content destination, not a dialog: it drops the modal close button and renders a plain common title (modal-header--embedded) matching other embedded views like Command Center. The session-list Back affordance stays because it navigates within Planning, not away from the view.
         */}
         <div className={isEmbedded ? "modal-header modal-header--embedded" : "modal-header"}>
           <div className="detail-title-row">
             {canReturnToSessionList && (
               <button
-                className="modal-back planning-mobile-back"
+                className="modal-back planning-session-back"
                 onClick={handleBackToList}
                 aria-label={t("planning.backToSessions", "Back to sessions")}
                 title={t("planning.backToSessions", "Back to sessions")}
@@ -2867,26 +2867,13 @@ export function PlanningModeModal({ isOpen, onClose, onTaskCreated, onTasksCreat
             )}
           </div>
           {/*
-          FNXC:PlanningModeMobileTablet 2026-07-20-09:12:
-          When the viewport cannot fit three interview panes, operators must still be able to return
-          to the session list and then back to the active question. Keep the list and detail state
-          synchronized on both transitions so a second Sessions press cannot leave the question pane
-          hidden by the mobile list CSS.
+          FNXC:PlanningSessionBack 2026-07-21-11:15:
+          History remains the only detail action in this group. Session-list navigation lives in the
+          title-row Back control on every viewport, avoiding a duplicate Sessions toggle and keeping
+          compact list/detail state synchronized through one handler.
           */}
           {selectedSessionId && (view.type === "question" || view.type === "loading" || view.type === "error" || view.type === "plan_review" || view.type === "create_retry") && (
             <div className="planning-header-controls">
-              <button
-                type="button"
-                className="btn"
-                onClick={() => {
-                  const showList = !isSessionListMode;
-                  setIsHistoryOpen(false);
-                  setShowSessionList(showList);
-                  if (isCompactInterview) setMobileShowDetail(!showList);
-                }}
-              >
-                {t("planning.sessions", "Sessions")}
-              </button>
               <button
                 ref={historyTriggerRef}
                 type="button"
diff --git a/packages/dashboard/app/components/__tests__/PlanningModeModal.css.test.ts b/packages/dashboard/app/components/__tests__/PlanningModeModal.css.test.ts
index 76f578a306..160299ee5a 100644
--- a/packages/dashboard/app/components/__tests__/PlanningModeModal.css.test.ts
+++ b/packages/dashboard/app/components/__tests__/PlanningModeModal.css.test.ts
@@ -115,12 +115,16 @@ describe("PlanningModeModal CSS responsive action contract", () => {
 
   it("uses consistent full-width header controls without crowding the mobile session title", () => {
     const css = loadPlanningCss();
+    const backRule = findRule(css, ".planning-session-back");
     expect(findRule(css, ".planning-header-controls")).toMatch(/gap\s*:\s*var\(--space-sm\)\s*;/);
     expect(findRule(css, ".planning-header-controls .btn")).toMatch(/min-height\s*:\s*calc\(var\(--space-2xl\) \+ var\(--space-sm\)\)\s*;/);
+    expect(backRule).toMatch(/display\s*:\s*inline-flex\s*;/);
+    expect(backRule).toMatch(/min-width\s*:\s*calc\(var\(--space-md\) \* 2\.25\)\s*;/);
+    expect(backRule).toMatch(/min-height\s*:\s*calc\(var\(--space-md\) \* 2\.25\)\s*;/);
 
     const mobileCss = getMediaBlocks(css, MOBILE_ACTIONS_QUERY).join("\n");
     expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded")).toMatch(/flex-wrap\s*:\s*wrap\s*;/);
-    expect(findRule(mobileCss, ".planning-header-controls")).toMatch(/grid-template-columns\s*:\s*repeat\(2, minmax\(0, 1fr\)\)\s*;/);
+    expect(findRule(mobileCss, ".planning-header-controls")).toMatch(/grid-template-columns\s*:\s*minmax\(0, 1fr\)\s*;/);
     expect(findRule(mobileCss, ".planning-header-controls")).toMatch(/width\s*:\s*100%\s*;/);
     expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded .detail-title-row")).toMatch(/flex-wrap\s*:\s*nowrap\s*;/);
     expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded .detail-title-row")).toMatch(/overflow\s*:\s*hidden\s*;/);
@@ -128,7 +132,7 @@ describe("PlanningModeModal CSS responsive action contract", () => {
     expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded .detail-title-row h3")).toMatch(/min-width\s*:\s*0\s*;/);
     expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded .detail-title-row h3")).toMatch(/text-overflow\s*:\s*ellipsis\s*;/);
     expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded .detail-title-row h3")).toMatch(/white-space\s*:\s*nowrap\s*;/);
-    expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded .detail-title-row > svg,\n  .planning-modal--embedded .modal-header--embedded .detail-title-row > .btn-icon,\n  .planning-modal--embedded .modal-header--embedded .planning-mobile-back")).toMatch(/flex\s*:\s*0 0 auto\s*;/);
+    expect(findRule(mobileCss, ".planning-modal--embedded .modal-header--embedded .detail-title-row > svg,\n  .planning-modal--embedded .modal-header--embedded .detail-title-row > .btn-icon,\n  .planning-modal--embedded .modal-header--embedded .planning-session-back")).toMatch(/flex\s*:\s*0 0 auto\s*;/);
   });
 
   it("keeps tablet question and plan actions on one aligned row with a tight bottom inset", () => {
@@ -173,9 +177,5 @@ describe("PlanningModeModal CSS responsive action contract", () => {
     const footerRule = findRule(mobileShellCss, ".planning-modal-body--show-list .planning-sidebar-footer");
     expect(footerRule).toBeTruthy();
     expect(footerRule).toMatch(/flex-shrink\s*:\s*0\s*;/);
-
-    const mobileBackRule = findRule(mobileShellCss, ".planning-mobile-back");
-    expect(mobileBackRule).toMatch(/display\s*:\s*inline-flex\s*;/);
-    expect(mobileBackRule).toMatch(/min-height\s*:\s*calc\(var\(--space-md\) \* 2\.25\)\s*;/);
   });
 });
diff --git a/packages/dashboard/app/components/__tests__/PlanningModeModal.initial.test.tsx b/packages/dashboard/app/components/__tests__/PlanningModeModal.initial.test.tsx
index 09ccca960e..36de10d2f4 100644
--- a/packages/dashboard/app/components/__tests__/PlanningModeModal.initial.test.tsx
+++ b/packages/dashboard/app/components/__tests__/PlanningModeModal.initial.test.tsx
@@ -3,7 +3,7 @@ import { readFileSync } from "node:fs";
 import { resolve } from "node:path";
 
 describe("PlanningModeModal initial surface", () => {
-  it("keeps Sessions as the single escape hatch while the active interview is sequential", () => {
+  it("keeps the sequential interview surfaces available", () => {
     const source = readFileSync(resolve(process.cwd(), "app/components/PlanningModeModal.tsx"), "utf8");
     expect(source).toContain('data-testid="planning-plan-review"');
     expect(source).toContain('data-testid="planning-refine-menu"');
diff --git a/packages/dashboard/app/components/__tests__/PlanningModeModal.planning-flow.test.tsx b/packages/dashboard/app/components/__tests__/PlanningModeModal.planning-flow.test.tsx
index cd0bd70226..ba001670a9 100644
--- a/packages/dashboard/app/components/__tests__/PlanningModeModal.planning-flow.test.tsx
+++ b/packages/dashboard/app/components/__tests__/PlanningModeModal.planning-flow.test.tsx
@@ -3,7 +3,7 @@ import { act, fireEvent, render, screen, waitFor } from "@testing-library/react"
 import { PlanningModeModal } from "../PlanningModeModal";
 import { mockCreatePlanningDraft, mockFetchAiSession, mockFetchAiSessions, mockRespondToPlanning, mockRetryPlanningSession, mockStartPlanningStreaming, mockStopPlanningGeneration, mockValidatePlanningSession, mockCreateTaskFromPlanning, mockTasks, mockSummary } from "./PlanningModeModal.test-helpers";
 
-const mockViewportMode = vi.hoisted(() => vi.fn(() => "desktop" as "desktop" | "mobile"));
+const mockViewportMode = vi.hoisted(() => vi.fn(() => "desktop" as "desktop" | "tablet" | "mobile"));
 const mockConnectPlanningStream = vi.hoisted(() => vi.fn());
 const mockPlanningSse = vi.hoisted(() => ({ events: null as Record<string, (event: MessageEvent) => void> | null }));
 
@@ -263,7 +263,7 @@ describe("PlanningModeModal sequential flow", () => {
     expect(screen.queryByRole("checkbox", { name: "Security boundaries" })).toBeNull();
     expect(screen.getByRole("button", { name: "Refine" })).toBeEnabled();
     expect(screen.getByRole("button", { name: "Proceed with plan" })).toBeInTheDocument();
-    expect(screen.getByRole("button", { name: "Sessions" })).toBeInTheDocument();
+    expect(screen.queryByRole("button", { name: "Sessions" })).toBeNull();
     const scrollRegion = screen.getByTestId("planning-plan-scroll");
     const actionBar = screen.getByTestId("planning-plan-actions");
     expect(scrollRegion).not.toContainElement(actionBar);
@@ -301,7 +301,7 @@ describe("PlanningModeModal sequential flow", () => {
     expect(mockConnectPlanningStream).not.toHaveBeenCalled();
   });
 
-  it("opens question, answer, and collapsed AI reasoning history beside Sessions", async () => {
+  it("opens question, answer, and collapsed AI reasoning history without a Sessions toggle", async () => {
     mockFetchAiSession.mockResolvedValue({
       ...base,
       status: "awaiting_input",
@@ -321,9 +321,8 @@ describe("PlanningModeModal sequential flow", () => {
     });
     renderSession();
 
-    const sessionsButton = await screen.findByRole("button", { name: "Sessions" });
-    const historyButton = screen.getByRole("button", { name: "History" });
-    expect(sessionsButton.parentElement).toContainElement(historyButton);
+    const historyButton = await screen.findByRole("button", { name: "History" });
+    expect(screen.queryByRole("button", { name: "Sessions" })).toBeNull();
     fireEvent.click(historyButton);
 
     expect(screen.getByRole("region", { name: "Question and answer history" })).toBeInTheDocument();
@@ -343,6 +342,55 @@ describe("PlanningModeModal sequential flow", () => {
     await waitFor(() => expect(historyButton).toHaveFocus());
   });
 
+  /*
+  FNXC:PlanningSessionBack 2026-07-21-11:15:
+  Session detail navigation has one invariant across desktop and compact layouts: Back is the
+  only route to the saved-session list. The former Sessions toggle must not survive as a second
+  affordance, and list mode must not retain an orphaned Back target.
+  */
+  it.each(["desktop", "tablet", "mobile"] as const)("uses only Back to return to sessions on %s", async (viewport) => {
+    mockViewportMode.mockReturnValue(viewport);
+    mockFetchAiSession.mockResolvedValue({
+      ...base,
+      status: "awaiting_input",
+      currentQuestion: JSON.stringify({ id: "q-current", type: "text", question: "What should happen next?" }),
+      result: JSON.stringify(summaryWithRefinements),
+      inputPayload: "{}",
+    });
+
+    renderSession();
+
+    const backButton = await screen.findByRole("button", { name: "Back to sessions" });
+    const modalBody = document.querySelector(".planning-modal-body");
+    expect(screen.queryByRole("button", { name: "Sessions" })).toBeNull();
+    fireEvent.click(screen.getByRole("button", { name: "History" }));
+    expect(screen.getByRole("region", { name: "Question and answer history" })).toBeInTheDocument();
+    fireEvent.click(backButton);
+
+    expect(modalBody).toHaveClass("planning-modal-body--show-list");
+    expect(screen.queryByRole("button", { name: "Back to sessions" })).toBeNull();
+    expect(screen.queryByRole("region", { name: "Question and answer history" })).toBeNull();
+    expect(screen.getByRole("complementary", { name: "Planning sessions" })).toBeInTheDocument();
+  });
+
+  it.each(["desktop", "tablet", "mobile"] as const)("keeps Back available from a new-session draft with saved sessions on %s", async (viewport) => {
+    mockViewportMode.mockReturnValue(viewport);
+    mockFetchAiSessions.mockResolvedValue([{
+      ...base,
+      type: "planning",
+      status: "awaiting_input",
+      preview: "Saved plan",
+    }]);
+
+    render(<PlanningModeModal isOpen onClose={vi.fn()} onTaskCreated={vi.fn()} onTasksCreated={vi.fn()} tasks={mockTasks} projectId="project-1" />);
+
+    if (viewport !== "desktop") {
+      fireEvent.click(await screen.findByRole("button", { name: "New session" }));
+    }
+    expect(await screen.findByRole("button", { name: "Back to sessions" })).toBeInTheDocument();
+    expect(screen.queryByRole("button", { name: "Sessions" })).toBeNull();
+  });
+
   it("creates the task directly and offers task and session-list handoffs", async () => {
     mockFetchAiSession.mockResolvedValue({
       ...base,