diff --git a/canvas/src/components/tabs/ContainerConfigTab.tsx b/canvas/src/components/tabs/ContainerConfigTab.tsx
index f8a3259c0..24813e1a8 100644
--- a/canvas/src/components/tabs/ContainerConfigTab.tsx
+++ b/canvas/src/components/tabs/ContainerConfigTab.tsx
@@ -29,8 +29,15 @@ type FormState = {
   displayMode: string;
   displayProtocol: string;
   resolution: string;
+  dataPersistence: string; // "" (auto) | "persist" | "ephemeral" — internal#734
 };
 
+// internal#734: per-workspace durable-data choice. "" = auto (desktop-control
+// keeps data, others follow the org default). Human labels for the selector.
+const DATA_PERSISTENCE_OPTIONS = ["", "persist", "ephemeral"];
+const dataPersistenceLabel = (v: string): string =>
+  v === "persist" ? "Always keep (persist)" : v === "ephemeral" ? "Don't keep (ephemeral)" : "Auto";
+
 export function ContainerConfigTab({ workspaceId, data }: Props) {
   const runtime = data.runtime;
   const instanceType = data.compute?.instance_type;
@@ -39,9 +46,10 @@ export function ContainerConfigTab({ workspaceId, data }: Props) {
   const displayProtocol = data.compute?.display?.protocol;
   const displayWidth = data.compute?.display?.width;
   const displayHeight = data.compute?.display?.height;
+  const dataPersistence = data.compute?.data_persistence;
   const initial = useMemo(
-    () => formFromData({ runtime, instanceType, rootGB, displayMode, displayProtocol, displayWidth, displayHeight }),
-    [runtime, instanceType, rootGB, displayMode, displayProtocol, displayWidth, displayHeight],
+    () => formFromData({ runtime, instanceType, rootGB, displayMode, displayProtocol, displayWidth, displayHeight, dataPersistence }),
+    [runtime, instanceType, rootGB, displayMode, displayProtocol, displayWidth, displayHeight, dataPersistence],
   );
   const [form, setForm] = useState<FormState>(initial);
   const [saving, setSaving] = useState(false);
@@ -84,6 +92,8 @@ export function ContainerConfigTab({ workspaceId, data }: Props) {
           display: form.displayEnabled
             ? { mode: form.displayMode, protocol: form.displayProtocol, width, height }
             : { mode: "none" },
+          // internal#734: omit when "auto" so the wire/default behavior is unchanged.
+          ...(form.dataPersistence ? { data_persistence: form.dataPersistence } : {}),
         };
 
         const resp = await api.patch<{ needs_restart?: boolean }>(`/workspaces/${workspaceId}`, {
@@ -176,6 +186,18 @@ export function ContainerConfigTab({ workspaceId, data }: Props) {
               onChange={(resolution) => setForm((s) => ({ ...s, resolution }))}
             />
           )}
+          <SelectField
+            id="data-persistence"
+            label="Saved data (cookies, downloads, memory)"
+            value={form.dataPersistence}
+            options={DATA_PERSISTENCE_OPTIONS}
+            optionLabel={dataPersistenceLabel}
+            onChange={(dataPersistence) => setForm((s) => ({ ...s, dataPersistence }))}
+          />
+          <p className="-mt-1 text-[10px] leading-snug text-ink-soft">
+            Whether this workspace&apos;s data survives a restart/recreate. Auto keeps it for
+            browser (desktop) workspaces; Ephemeral never keeps it (privacy).
+          </p>
         </div>
 
         <div className="mt-4 flex items-center justify-end gap-2">
@@ -231,6 +253,7 @@ function formFromData(data: {
   displayProtocol?: string;
   displayWidth?: number;
   displayHeight?: number;
+  dataPersistence?: string;
 }): FormState {
   const width = data.displayWidth ?? 1920;
   const height = data.displayHeight ?? 1080;
@@ -243,6 +266,7 @@ function formFromData(data: {
     displayMode: data.displayMode && data.displayMode !== "none" ? data.displayMode : "desktop-control",
     displayProtocol: data.displayProtocol || "novnc",
     resolution,
+    dataPersistence: data.dataPersistence || "",
   };
 }
 
diff --git a/canvas/src/components/tabs/DetailsTab.tsx b/canvas/src/components/tabs/DetailsTab.tsx
index 197015ecb..d39cb554d 100644
--- a/canvas/src/components/tabs/DetailsTab.tsx
+++ b/canvas/src/components/tabs/DetailsTab.tsx
@@ -29,6 +29,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
   const [peers, setPeers] = useState<PeerData[]>([]);
   const [saving, setSaving] = useState(false);
   const [confirmDelete, setConfirmDelete] = useState(false);
+  const [eraseData, setEraseData] = useState(false); // internal#734: erase saved data on delete
   const [peersError, setPeersError] = useState<string | null>(null);
   const [saveError, setSaveError] = useState<string | null>(null);
   const [deleteError, setDeleteError] = useState<string | null>(null);
@@ -93,7 +94,10 @@ export function DetailsTab({ workspaceId, data }: Props) {
   const handleDelete = async () => {
     setDeleteError(null);
     try {
-      await api.del(`/workspaces/${workspaceId}?confirm=true`, {
+      // internal#734: erase_data=true asks the server to prune this workspace's
+      // durable data volume (cookies / downloads / memory). Default off keeps it
+      // for the orphan-sweeper grace.
+      await api.del(`/workspaces/${workspaceId}?confirm=true${eraseData ? "&erase_data=true" : ""}`, {
         headers: { "X-Confirm-Name": name },
       });
       // Mirror the server-side cascade — drop the row + every
@@ -323,6 +327,19 @@ export function DetailsTab({ workspaceId, data }: Props) {
             <h3 id="delete-confirm-title" className="text-xs font-medium text-bad">
               Confirm deletion
             </h3>
+            <label className="flex items-start gap-2 text-[11px] text-ink-mid">
+              <input
+                type="checkbox"
+                aria-label="Also erase saved data"
+                checked={eraseData}
+                onChange={(e) => setEraseData(e.target.checked)}
+                className="mt-0.5 h-3.5 w-3.5 accent-red-600"
+              />
+              <span>
+                Also erase saved data (cookies, downloads, agent memory). Cannot be undone.
+                Unchecked keeps it recoverable briefly.
+              </span>
+            </label>
             <div className="flex gap-2">
               <button
                 type="button"
@@ -339,6 +356,7 @@ export function DetailsTab({ workspaceId, data }: Props) {
                 onClick={() => {
                   setConfirmDelete(false);
                   setDeleteError(null);
+                  setEraseData(false);
                   // Return focus to the trigger so keyboard users aren't stranded
                   deleteButtonRef.current?.focus();
                 }}
diff --git a/canvas/src/components/tabs/__tests__/DetailsTab.test.tsx b/canvas/src/components/tabs/__tests__/DetailsTab.test.tsx
index 3c7bb59fd..26039ec1f 100644
--- a/canvas/src/components/tabs/__tests__/DetailsTab.test.tsx
+++ b/canvas/src/components/tabs/__tests__/DetailsTab.test.tsx
@@ -297,6 +297,25 @@ describe("DetailsTab — delete workflow", () => {
     expect(mockSelectNode).toHaveBeenCalledWith(null);
   });
 
+  // internal#734: checking "also erase saved data" adds &erase_data=true so the
+  // server prunes the data volume. Default (unchecked) must NOT send it.
+  it("checking erase-saved-data sends erase_data=true on delete", async () => {
+    mockApi.del.mockResolvedValue(undefined);
+    render(<DetailsTab workspaceId="ws-1" data={data()} />);
+    await flush();
+    fireEvent.click(screen.getByRole("button", { name: /delete workspace/i }));
+    await flush();
+    fireEvent.click(screen.getByRole("checkbox", { name: /erase saved data/i }));
+    const confirmBtn = Array.from(document.querySelectorAll("button")).find(
+      (b) => b.textContent === "Confirm Delete",
+    ) as HTMLButtonElement;
+    fireEvent(confirmBtn, new MouseEvent("click", { bubbles: true }));
+    await flush();
+    expect(mockApi.del).toHaveBeenCalledWith("/workspaces/ws-1?confirm=true&erase_data=true", {
+      headers: { "X-Confirm-Name": "Test Workspace" },
+    });
+  });
+
   it("cancelling delete returns to view mode", async () => {
     mockApi.del.mockResolvedValue(undefined);
     render(<DetailsTab workspaceId="ws-1" data={data()} />);
diff --git a/canvas/src/store/socket.ts b/canvas/src/store/socket.ts
index 4e3fe82b4..23bd86b69 100644
--- a/canvas/src/store/socket.ts
+++ b/canvas/src/store/socket.ts
@@ -368,6 +368,9 @@ export interface WorkspaceCompute {
     width?: number;
     height?: number;
   };
+  // internal#734: per-workspace durable-data choice. "persist" | "ephemeral" |
+  // undefined (auto). Controls whether the data volume survives recreate.
+  data_persistence?: string;
 }
 
 let socket: ReconnectingSocket | null = null;
diff --git a/workspace-server/internal/handlers/a2a_proxy_test.go b/workspace-server/internal/handlers/a2a_proxy_test.go
index 6a254a7f5..10b21cbda 100644
--- a/workspace-server/internal/handlers/a2a_proxy_test.go
+++ b/workspace-server/internal/handlers/a2a_proxy_test.go
@@ -16,9 +16,9 @@ import (
 	"testing"
 	"time"
 
-	"github.com/DATA-DOG/go-sqlmock"
 	"git.moleculesai.app/molecule-ai/molecule-core/workspace-server/internal/models"
 	"git.moleculesai.app/molecule-ai/molecule-core/workspace-server/internal/provisioner"
+	"github.com/DATA-DOG/go-sqlmock"
 	"github.com/gin-gonic/gin"
 )
 
@@ -2117,6 +2117,10 @@ func (f *fakeCPProv) Stop(_ context.Context, _ string) error {
 	f.stopCalls++
 	return nil
 }
+func (f *fakeCPProv) StopAndPrune(_ context.Context, _ string) error {
+	f.stopCalls++
+	return nil
+}
 func (f *fakeCPProv) GetConsoleOutput(_ context.Context, _ string) (string, error) {
 	return "", nil
 }
diff --git a/workspace-server/internal/handlers/org.go b/workspace-server/internal/handlers/org.go
index 0d9e87b39..1682b759d 100644
--- a/workspace-server/internal/handlers/org.go
+++ b/workspace-server/internal/handlers/org.go
@@ -875,7 +875,9 @@ func (h *OrgHandler) Import(c *gin.Context) {
 				rows.Close()
 
 				for _, oid := range orphanIDs {
-					descendantIDs, stopErrs, err := h.workspace.CascadeDelete(ctx, oid)
+					// erase=false: a reconcile is not a user-requested erase —
+					// never prune data volumes on the import-reconcile path (internal#734).
+					descendantIDs, stopErrs, err := h.workspace.CascadeDelete(ctx, oid, false)
 					if err != nil {
 						log.Printf("Org import reconcile: CascadeDelete(%s) failed: %v", oid, err)
 						reconcileErrs = append(reconcileErrs, fmt.Sprintf("delete %s: %v", oid, err))
diff --git a/workspace-server/internal/handlers/workspace_compute.go b/workspace-server/internal/handlers/workspace_compute.go
index 9ec1760b2..0824a655b 100644
--- a/workspace-server/internal/handlers/workspace_compute.go
+++ b/workspace-server/internal/handlers/workspace_compute.go
@@ -65,6 +65,14 @@ func validateWorkspaceCompute(compute models.WorkspaceCompute) error {
 	if err := validateWorkspaceDisplayDimensions(compute.Display.Width, compute.Display.Height); err != nil {
 		return err
 	}
+	// internal#734: the durable-data choice. CP re-validates the same enum at
+	// its provision edge (IsValidDataPersistence → 400); validating here too
+	// gives the user a clear workspace-server error before the CP round-trip.
+	switch compute.DataPersistence {
+	case "", "persist", "ephemeral":
+	default:
+		return fmt.Errorf("unsupported compute.data_persistence (want persist|ephemeral)")
+	}
 	return nil
 }
 
diff --git a/workspace-server/internal/handlers/workspace_compute_test.go b/workspace-server/internal/handlers/workspace_compute_test.go
index 38d07113c..ab212cb5a 100644
--- a/workspace-server/internal/handlers/workspace_compute_test.go
+++ b/workspace-server/internal/handlers/workspace_compute_test.go
@@ -11,8 +11,8 @@ import (
 	"testing"
 	"time"
 
-	"github.com/DATA-DOG/go-sqlmock"
 	"git.moleculesai.app/molecule-ai/molecule-core/workspace-server/internal/models"
+	"github.com/DATA-DOG/go-sqlmock"
 	"github.com/gin-gonic/gin"
 )
 
@@ -36,6 +36,23 @@ func TestValidateWorkspaceCompute_RejectsUnknownInstanceType(t *testing.T) {
 	}
 }
 
+// internal#734: data_persistence enum. "" (auto), "persist", "ephemeral" are
+// the only accepted values; anything else is a clear 400 before the CP call.
+func TestValidateWorkspaceCompute_DataPersistence(t *testing.T) {
+	for _, ok := range []string{"", "persist", "ephemeral"} {
+		c := models.WorkspaceCompute{DataPersistence: ok}
+		if err := validateWorkspaceCompute(c); err != nil {
+			t.Errorf("data_persistence=%q must be accepted: %v", ok, err)
+		}
+	}
+	for _, bad := range []string{"persistent", "off", "none", "Ephemeral", "true"} {
+		c := models.WorkspaceCompute{DataPersistence: bad}
+		if err := validateWorkspaceCompute(c); err == nil {
+			t.Errorf("data_persistence=%q must be rejected", bad)
+		}
+	}
+}
+
 func TestValidateWorkspaceCompute_RejectsOutOfRangeRootVolume(t *testing.T) {
 	for _, rootGB := range []int{29, 501} {
 		compute := models.WorkspaceCompute{Volume: models.WorkspaceComputeVolume{RootGB: rootGB}}
diff --git a/workspace-server/internal/handlers/workspace_crud.go b/workspace-server/internal/handlers/workspace_crud.go
index f122f4fb3..1c79ee2b8 100644
--- a/workspace-server/internal/handlers/workspace_crud.go
+++ b/workspace-server/internal/handlers/workspace_crud.go
@@ -399,7 +399,13 @@ func (h *WorkspaceHandler) Delete(c *gin.Context) {
 	// disable, broadcast). The HTTP-specific bits — direct-children 409
 	// gate above, ?purge=true hard-delete below, response shaping —
 	// stay in this handler.
-	descendantIDs, stopErrs, err := h.CascadeDelete(ctx, id)
+	// internal#734: the user can ask to erase saved data (browser profile /
+	// cookies / downloads / agent memory) on delete. Opt-in — default keeps the
+	// data on its volume for the orphan-sweeper grace. Only a genuine
+	// permanent-delete reaches here (restart/reconcile use other paths), so this
+	// is the one place prune may be requested.
+	erase := c.Query("erase_data") == "true"
+	descendantIDs, stopErrs, err := h.CascadeDelete(ctx, id, erase)
 	if err != nil {
 		// Audit 2026-05-09 (Core-Security): raw `err.Error()` here was
 		// exposed to HTTP clients verbatim, including wrapped lib/pq
@@ -515,7 +521,13 @@ func destructiveDeleteCounts(ctx context.Context, id string) (childCount int, sc
 // Caller is responsible for the children-confirmation gate (the HTTP handler
 // returns 409 when children exist + ?confirm=true is missing); this helper
 // always cascades.
-func (h *WorkspaceHandler) CascadeDelete(ctx context.Context, id string) ([]string, []error, error) {
+// CascadeDelete tears down a workspace and its descendants (stop compute,
+// remove volumes, revoke tokens, disable schedules, broadcast). erase=true
+// (internal#734) means the user asked to erase saved data, so the CP compute
+// teardown prunes each workspace's durable data volume; the HTTP delete passes
+// the user's choice, the org-import reconcile passes false (a reconcile is not
+// a user-erase).
+func (h *WorkspaceHandler) CascadeDelete(ctx context.Context, id string, erase bool) ([]string, []error, error) {
 	if err := validateWorkspaceID(id); err != nil {
 		return nil, nil, err
 	}
@@ -579,7 +591,7 @@ func (h *WorkspaceHandler) CascadeDelete(ctx context.Context, id string) ([]stri
 		// pending EC2 is queryable and handed off to the CP-orphan-sweeper —
 		// rather than the bare one-shot StopWorkspaceAuto that produced the
 		// silent-leak class (task #15 / workspace-ec2-leak).
-		if err := h.stopWorkspaceForDelete(cleanupCtx, wsID); err != nil {
+		if err := h.stopWorkspaceForDelete(cleanupCtx, wsID, erase); err != nil {
 			log.Printf("CascadeDelete %s stop failed: %v — leaving cleanup for orphan sweeper", wsID, err)
 			stopErrs = append(stopErrs, fmt.Errorf("stop %s: %w", wsID, err))
 			return
diff --git a/workspace-server/internal/handlers/workspace_crud_test.go b/workspace-server/internal/handlers/workspace_crud_test.go
index 8010e7c00..7988ac649 100644
--- a/workspace-server/internal/handlers/workspace_crud_test.go
+++ b/workspace-server/internal/handlers/workspace_crud_test.go
@@ -521,7 +521,7 @@ func TestValidateWorkspaceDir_Empty(t *testing.T) {
 
 func TestCascadeDelete_InvalidUUID(t *testing.T) {
 	h := &WorkspaceHandler{}
-	descendants, stopErrs, err := h.CascadeDelete(context.Background(), "not-a-uuid")
+	descendants, stopErrs, err := h.CascadeDelete(context.Background(), "not-a-uuid", false)
 	if err == nil {
 		t.Error("expected error for invalid UUID")
 	}
@@ -542,7 +542,7 @@ func TestCascadeDelete_DescendantQueryError(t *testing.T) {
 		WithArgs(wsID).
 		WillReturnError(sql.ErrConnDone)
 
-	deleted, stopErrs, err := h.CascadeDelete(context.Background(), wsID)
+	deleted, stopErrs, err := h.CascadeDelete(context.Background(), wsID, false)
 	if err == nil {
 		t.Error("CascadeDelete returned nil error; want descendant query error")
 	}
@@ -569,7 +569,7 @@ func TestCascadeDelete_DescendantRowsError(t *testing.T) {
 		WithArgs(wsID).
 		WillReturnRows(rows)
 
-	deleted, stopErrs, err := h.CascadeDelete(context.Background(), wsID)
+	deleted, stopErrs, err := h.CascadeDelete(context.Background(), wsID, false)
 	if err == nil {
 		t.Fatal("CascadeDelete returned nil error; want descendant rows error")
 	}
diff --git a/workspace-server/internal/handlers/workspace_delete_stop_retry_test.go b/workspace-server/internal/handlers/workspace_delete_stop_retry_test.go
index 480c49c45..6889bff67 100644
--- a/workspace-server/internal/handlers/workspace_delete_stop_retry_test.go
+++ b/workspace-server/internal/handlers/workspace_delete_stop_retry_test.go
@@ -45,7 +45,7 @@ func TestStopWorkspaceForDelete_CPRetriesTransientThenSucceeds(t *testing.T) {
 	}}
 	h := &WorkspaceHandler{cpProv: stub}
 
-	err := h.stopWorkspaceForDelete(context.Background(), "ws-del-1")
+	err := h.stopWorkspaceForDelete(context.Background(), "ws-del-1", false)
 	if err != nil {
 		t.Fatalf("expected nil error on eventual success, got %v", err)
 	}
@@ -73,7 +73,7 @@ func TestStopWorkspaceForDelete_CPExhaustsEmitsDurableEventAndReturnsError(t *te
 	mock.ExpectExec("INSERT INTO structure_events").
 		WillReturnResult(sqlmock.NewResult(0, 1))
 
-	err := h.stopWorkspaceForDelete(context.Background(), "ws-doomed")
+	err := h.stopWorkspaceForDelete(context.Background(), "ws-doomed", false)
 	if err == nil {
 		t.Fatal("expected terminal error on retry exhaustion, got nil")
 	}
@@ -96,7 +96,7 @@ func TestStopWorkspaceForDelete_CPExhaustsEmitsDurableEventAndReturnsError(t *te
 
 func TestStopWorkspaceForDelete_NoBackendIsNoOp(t *testing.T) {
 	h := &WorkspaceHandler{} // cpProv nil, provisioner nil
-	if err := h.stopWorkspaceForDelete(context.Background(), "ws-x"); err != nil {
+	if err := h.stopWorkspaceForDelete(context.Background(), "ws-x", false); err != nil {
 		t.Errorf("expected nil no-op with no backend, got %v", err)
 	}
 }
diff --git a/workspace-server/internal/handlers/workspace_dispatchers.go b/workspace-server/internal/handlers/workspace_dispatchers.go
index 0ebcf7696..a739d5818 100644
--- a/workspace-server/internal/handlers/workspace_dispatchers.go
+++ b/workspace-server/internal/handlers/workspace_dispatchers.go
@@ -235,9 +235,13 @@ func (h *WorkspaceHandler) StopWorkspaceAuto(ctx context.Context, workspaceID st
 // container won't heal on retry (matches RestartWorkspaceAuto's Docker
 // rationale); the orphan-container sweeper (registry/orphan_sweeper.go) is
 // the Docker-side backstop.
-func (h *WorkspaceHandler) stopWorkspaceForDelete(ctx context.Context, workspaceID string) error {
+// stopWorkspaceForDelete terminates a workspace's compute on the delete path.
+// erase=true (internal#734) means the user asked to erase saved data, so the CP
+// teardown prunes the durable data volume. The local-docker path always removes
+// its volume via CascadeDelete's RemoveVolume, so erase is a CP-only concern.
+func (h *WorkspaceHandler) stopWorkspaceForDelete(ctx context.Context, workspaceID string, erase bool) error {
 	if h.cpProv != nil {
-		if err := h.cpStopWithRetryErr(ctx, workspaceID, "Delete"); err != nil {
+		if err := h.cpStopWithRetryErr(ctx, workspaceID, "Delete", erase); err != nil {
 			h.emitDeleteTerminateRetryExhausted(ctx, workspaceID, err)
 			return err
 		}
diff --git a/workspace-server/internal/handlers/workspace_provision.go b/workspace-server/internal/handlers/workspace_provision.go
index 92439db52..da5e71f1e 100644
--- a/workspace-server/internal/handlers/workspace_provision.go
+++ b/workspace-server/internal/handlers/workspace_provision.go
@@ -330,6 +330,7 @@ func (h *WorkspaceHandler) buildProvisionerConfig(
 		Runtime:         payload.Runtime,
 		InstanceType:    payload.Compute.InstanceType,
 		DiskGB:          int32(payload.Compute.Volume.RootGB),
+		DataPersistence: payload.Compute.DataPersistence,
 		Display: provisioner.WorkspaceDisplayConfig{
 			Mode:     payload.Compute.Display.Mode,
 			Width:    payload.Compute.Display.Width,
diff --git a/workspace-server/internal/handlers/workspace_provision_auto_test.go b/workspace-server/internal/handlers/workspace_provision_auto_test.go
index b856b79c2..3ce0ee3cb 100644
--- a/workspace-server/internal/handlers/workspace_provision_auto_test.go
+++ b/workspace-server/internal/handlers/workspace_provision_auto_test.go
@@ -42,6 +42,7 @@ type trackingCPProv struct {
 	mu       sync.Mutex
 	started  []string
 	stopped  []string
+	pruned   []string // internal#734: workspaces stopped via StopAndPrune
 	startErr error
 	stopErr  error
 }
@@ -61,6 +62,13 @@ func (r *trackingCPProv) Stop(_ context.Context, workspaceID string) error {
 	r.mu.Unlock()
 	return r.stopErr
 }
+func (r *trackingCPProv) StopAndPrune(_ context.Context, workspaceID string) error {
+	r.mu.Lock()
+	r.stopped = append(r.stopped, workspaceID)
+	r.pruned = append(r.pruned, workspaceID)
+	r.mu.Unlock()
+	return r.stopErr
+}
 func (r *trackingCPProv) GetConsoleOutput(_ context.Context, _ string) (string, error) {
 	return "", nil
 }
diff --git a/workspace-server/internal/handlers/workspace_provision_concurrent_repro_test.go b/workspace-server/internal/handlers/workspace_provision_concurrent_repro_test.go
index 93e80735d..e240ce6a4 100644
--- a/workspace-server/internal/handlers/workspace_provision_concurrent_repro_test.go
+++ b/workspace-server/internal/handlers/workspace_provision_concurrent_repro_test.go
@@ -10,9 +10,9 @@ import (
 	"sync/atomic"
 	"testing"
 
-	"github.com/DATA-DOG/go-sqlmock"
 	"git.moleculesai.app/molecule-ai/molecule-core/workspace-server/internal/models"
 	"git.moleculesai.app/molecule-ai/molecule-core/workspace-server/internal/provisioner"
+	"github.com/DATA-DOG/go-sqlmock"
 )
 
 // Issue #2486 reproduction harness: 7 simultaneous claude-code provisions
@@ -71,6 +71,9 @@ func (r *recordingCPProv) Start(_ context.Context, cfg provisioner.WorkspaceConf
 func (r *recordingCPProv) Stop(_ context.Context, _ string) error {
 	panic("recordingCPProv.Stop not expected in concurrent-repro test")
 }
+func (r *recordingCPProv) StopAndPrune(_ context.Context, _ string) error {
+	panic("recordingCPProv.StopAndPrune not expected in concurrent-repro test")
+}
 
 func (r *recordingCPProv) GetConsoleOutput(_ context.Context, _ string) (string, error) {
 	panic("recordingCPProv.GetConsoleOutput not expected in concurrent-repro test")
diff --git a/workspace-server/internal/handlers/workspace_provision_test.go b/workspace-server/internal/handlers/workspace_provision_test.go
index b76c3166a..4cd5b844e 100644
--- a/workspace-server/internal/handlers/workspace_provision_test.go
+++ b/workspace-server/internal/handlers/workspace_provision_test.go
@@ -1399,6 +1399,9 @@ func (s *stubFailingCPProv) Start(_ context.Context, _ provisioner.WorkspaceConf
 func (s *stubFailingCPProv) Stop(_ context.Context, _ string) error {
 	panic("stubFailingCPProv.Stop not expected on the provisionWorkspaceCP failure path")
 }
+func (s *stubFailingCPProv) StopAndPrune(_ context.Context, _ string) error {
+	panic("stubFailingCPProv.StopAndPrune not expected on the provisionWorkspaceCP failure path")
+}
 
 func (s *stubFailingCPProv) GetConsoleOutput(_ context.Context, _ string) (string, error) {
 	panic("stubFailingCPProv.GetConsoleOutput not expected on the provisionWorkspaceCP failure path")
diff --git a/workspace-server/internal/handlers/workspace_restart.go b/workspace-server/internal/handlers/workspace_restart.go
index 8bae4ef61..04992b06b 100644
--- a/workspace-server/internal/handlers/workspace_restart.go
+++ b/workspace-server/internal/handlers/workspace_restart.go
@@ -726,7 +726,7 @@ func (h *WorkspaceHandler) cpStopWithRetry(ctx context.Context, workspaceID, sou
 	// terminal error. The delete path needs the error (it must keep the
 	// row recoverable for the orphan-sweeper + emit a durable event), so
 	// the actual retry loop lives in cpStopWithRetryErr below.
-	_ = h.cpStopWithRetryErr(ctx, workspaceID, source)
+	_ = h.cpStopWithRetryErr(ctx, workspaceID, source, false) // restart/hibernate never prunes
 }
 
 // cpStopWithRetryErr is the shared bounded-retry core for cpProv.Stop.
@@ -743,14 +743,24 @@ func (h *WorkspaceHandler) cpStopWithRetry(ctx context.Context, workspaceID, sou
 //   - all attempts fail   → returns the LAST attempt's error and emits the
 //     stable `LEAK-SUSPECT cpProv.Stop ...` log line so the CP-side orphan
 //     reconciler can correlate by workspace_id.
-func (h *WorkspaceHandler) cpStopWithRetryErr(ctx context.Context, workspaceID, source string) error {
+//
+// cpStopWithRetryErr terminates the workspace's CP-managed compute with bounded
+// retry. prune=true (internal#734) additionally requests CP erase the durable
+// data volume — set ONLY by the permanent-delete-with-erase path, NEVER by
+// restart/hibernate (those pass false), so a recreate can never prune.
+func (h *WorkspaceHandler) cpStopWithRetryErr(ctx context.Context, workspaceID, source string, prune bool) error {
 	if h.cpProv == nil {
 		return nil
 	}
 	var lastErr error
 	delay := cpStopRetryBaseDelay
 	for attempt := 1; attempt <= cpStopRetryAttempts; attempt++ {
-		err := h.cpProv.Stop(ctx, workspaceID)
+		var err error
+		if prune {
+			err = h.cpProv.StopAndPrune(ctx, workspaceID)
+		} else {
+			err = h.cpProv.Stop(ctx, workspaceID)
+		}
 		if err == nil {
 			if attempt > 1 {
 				log.Printf("%s: cpProv.Stop(%s) succeeded on attempt %d", source, workspaceID, attempt)
diff --git a/workspace-server/internal/handlers/workspace_restart_stop_retry_test.go b/workspace-server/internal/handlers/workspace_restart_stop_retry_test.go
index 0c7dcf4c6..bd2bfeda2 100644
--- a/workspace-server/internal/handlers/workspace_restart_stop_retry_test.go
+++ b/workspace-server/internal/handlers/workspace_restart_stop_retry_test.go
@@ -72,6 +72,13 @@ func (s *scriptedCPStop) Stop(ctx context.Context, _ string) error {
 	}
 	return nil
 }
+
+// StopAndPrune delegates to Stop so the retry/error scripting is identical —
+// the prune flag only changes the URL the real provisioner builds, not the
+// retry behavior these tests exercise.
+func (s *scriptedCPStop) StopAndPrune(ctx context.Context, id string) error {
+	return s.Stop(ctx, id)
+}
 func (s *scriptedCPStop) Start(_ context.Context, _ provisioner.WorkspaceConfig) (string, error) {
 	return "", nil
 }
diff --git a/workspace-server/internal/models/workspace.go b/workspace-server/internal/models/workspace.go
index a23bccd9e..a43a162bb 100644
--- a/workspace-server/internal/models/workspace.go
+++ b/workspace-server/internal/models/workspace.go
@@ -168,6 +168,12 @@ type WorkspaceCompute struct {
 	InstanceType string                  `json:"instance_type,omitempty"`
 	Volume       WorkspaceComputeVolume  `json:"volume,omitempty"`
 	Display      WorkspaceComputeDisplay `json:"display,omitempty"`
+	// DataPersistence is the per-workspace durable-data choice (internal#734):
+	// "persist" keeps the workspace's data volume (browser profile / cookies /
+	// downloads / agent memory) across recreate; "ephemeral" uses no durable
+	// disk (wiped each recreate — privacy); "" = auto (desktop-control persists,
+	// others follow the org flag). Forwarded verbatim to CP's data_persistence.
+	DataPersistence string `json:"data_persistence,omitempty"`
 }
 
 type CreateWorkspacePayload struct {
diff --git a/workspace-server/internal/provisioner/cp_provisioner.go b/workspace-server/internal/provisioner/cp_provisioner.go
index 804831e1a..93ee0fe48 100644
--- a/workspace-server/internal/provisioner/cp_provisioner.go
+++ b/workspace-server/internal/provisioner/cp_provisioner.go
@@ -32,6 +32,9 @@ import (
 type CPProvisionerAPI interface {
 	Start(ctx context.Context, cfg WorkspaceConfig) (string, error)
 	Stop(ctx context.Context, workspaceID string) error
+	// StopAndPrune is Stop + "erase the durable data volume" (internal#734),
+	// for the permanent-delete-with-erase flow ONLY. Restart/recreate use Stop.
+	StopAndPrune(ctx context.Context, workspaceID string) error
 	GetConsoleOutput(ctx context.Context, workspaceID string) (string, error)
 	// IsRunning reports whether the workspace's compute (EC2 instance) is
 	// currently in the running state. Surfaced on the interface (rather than
@@ -152,15 +155,19 @@ func (p *CPProvisioner) adminAuthHeaders(req *http.Request) {
 }
 
 type cpProvisionRequest struct {
-	OrgID        string                 `json:"org_id"`
-	WorkspaceID  string                 `json:"workspace_id"`
-	Runtime      string                 `json:"runtime"`
-	Tier         int                    `json:"tier"`
-	InstanceType string                 `json:"instance_type,omitempty"`
-	DiskGB       int32                  `json:"disk_gb,omitempty"`
-	Display      WorkspaceDisplayConfig `json:"display,omitempty"`
-	PlatformURL  string                 `json:"platform_url"`
-	Env          map[string]string      `json:"env"`
+	OrgID        string `json:"org_id"`
+	WorkspaceID  string `json:"workspace_id"`
+	Runtime      string `json:"runtime"`
+	Tier         int    `json:"tier"`
+	InstanceType string `json:"instance_type,omitempty"`
+	DiskGB       int32  `json:"disk_gb,omitempty"`
+	// DataPersistence is the per-workspace durable-data choice (internal#734);
+	// CP validates the enum at its provision edge and resolves the data volume
+	// from it. Empty = auto (omitted on the wire).
+	DataPersistence string                 `json:"data_persistence,omitempty"`
+	Display         WorkspaceDisplayConfig `json:"display,omitempty"`
+	PlatformURL     string                 `json:"platform_url"`
+	Env             map[string]string      `json:"env"`
 	// ConfigFiles are template + generated config files to write into the
 	// EC2 instance's /configs directory. OFFSEC-010: collected by
 	// collectCPConfigFiles which rejects symlinks and non-regular files
@@ -211,16 +218,17 @@ func (p *CPProvisioner) Start(ctx context.Context, cfg WorkspaceConfig) (string,
 	}
 
 	req := cpProvisionRequest{
-		OrgID:        p.orgID,
-		WorkspaceID:  cfg.WorkspaceID,
-		Runtime:      cfg.Runtime,
-		Tier:         cfg.Tier,
-		InstanceType: cfg.InstanceType,
-		DiskGB:       cfg.DiskGB,
-		Display:      cfg.Display,
-		PlatformURL:  cfg.PlatformURL,
-		Env:          env,
-		ConfigFiles:  configFiles,
+		OrgID:           p.orgID,
+		WorkspaceID:     cfg.WorkspaceID,
+		Runtime:         cfg.Runtime,
+		Tier:            cfg.Tier,
+		InstanceType:    cfg.InstanceType,
+		DiskGB:          cfg.DiskGB,
+		DataPersistence: cfg.DataPersistence,
+		Display:         cfg.Display,
+		PlatformURL:     cfg.PlatformURL,
+		Env:             env,
+		ConfigFiles:     configFiles,
 	}
 
 	body, err := json.Marshal(req)
@@ -398,6 +406,20 @@ func collectCPConfigFiles(cfg WorkspaceConfig) (map[string]string, error) {
 // blocking the next provision with InvalidGroup.Duplicate — a full
 // "Save & Restart" crash on SaaS.
 func (p *CPProvisioner) Stop(ctx context.Context, workspaceID string) error {
+	return p.stopInternal(ctx, workspaceID, false)
+}
+
+// StopAndPrune terminates the workspace's compute AND requests that its durable
+// data volume (browser profile / cookies / downloads / agent memory) be erased
+// (internal#734). Used ONLY by the permanent-delete flow when the user chose to
+// erase saved data — NEVER by restart/recreate (which call Stop), so a recreate
+// can never trigger a prune. CP enforces this defensively too (the prune is a
+// short-grace mark-then-sweep gated on the workspace being genuinely gone).
+func (p *CPProvisioner) StopAndPrune(ctx context.Context, workspaceID string) error {
+	return p.stopInternal(ctx, workspaceID, true)
+}
+
+func (p *CPProvisioner) stopInternal(ctx context.Context, workspaceID string, prune bool) error {
 	if p == nil {
 		return ErrNoBackend
 	}
@@ -420,6 +442,10 @@ func (p *CPProvisioner) Stop(ctx context.Context, workspaceID string) error {
 		return ErrNoBackend
 	}
 	url := fmt.Sprintf("%s/cp/workspaces/%s?instance_id=%s", p.baseURL, workspaceID, instanceID)
+	if prune {
+		// internal#734: ask CP to erase the data volume on this delete.
+		url += "&prune=true"
+	}
 	req, err := http.NewRequestWithContext(ctx, "DELETE", url, nil)
 	if err != nil {
 		return fmt.Errorf("cp provisioner: stop: build request: %w", err)
diff --git a/workspace-server/internal/provisioner/cp_provisioner_test.go b/workspace-server/internal/provisioner/cp_provisioner_test.go
index 35af6ca6c..75b366b22 100644
--- a/workspace-server/internal/provisioner/cp_provisioner_test.go
+++ b/workspace-server/internal/provisioner/cp_provisioner_test.go
@@ -1096,3 +1096,41 @@ func TestCollectCPConfigFiles_RejectsRootSymlink(t *testing.T) {
 		t.Errorf("expected symlink-related error, got: %v", err)
 	}
 }
+
+// internal#734 (F1): the prune signal must reach CP ONLY via StopAndPrune.
+// Stop must NEVER append prune=true (restart/recreate use Stop, and a prune on
+// a recreate = data loss). Captures the DELETE URL and asserts the contract.
+func TestStopVsStopAndPrune_PruneQueryParam(t *testing.T) {
+	primeInstanceIDLookup(t, map[string]string{"ws-keep": "i-keep", "ws-erase": "i-erase"})
+
+	var gotURL string
+	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		gotURL = r.URL.String()
+		w.WriteHeader(http.StatusOK)
+		_, _ = io.WriteString(w, `{"status":"terminated"}`)
+	}))
+	defer srv.Close()
+	p := &CPProvisioner{baseURL: srv.URL, orgID: "org-1", httpClient: srv.Client()}
+
+	// Stop → no prune.
+	if err := p.Stop(context.Background(), "ws-keep"); err != nil {
+		t.Fatalf("Stop: %v", err)
+	}
+	if strings.Contains(gotURL, "prune=true") {
+		t.Errorf("Stop must NOT send prune=true (recreate-safety); url=%s", gotURL)
+	}
+	if !strings.Contains(gotURL, "instance_id=i-keep") {
+		t.Errorf("Stop url missing instance_id; url=%s", gotURL)
+	}
+
+	// StopAndPrune → prune=true.
+	if err := p.StopAndPrune(context.Background(), "ws-erase"); err != nil {
+		t.Fatalf("StopAndPrune: %v", err)
+	}
+	if !strings.Contains(gotURL, "prune=true") {
+		t.Errorf("StopAndPrune MUST send prune=true; url=%s", gotURL)
+	}
+	if !strings.Contains(gotURL, "instance_id=i-erase") {
+		t.Errorf("StopAndPrune url missing instance_id; url=%s", gotURL)
+	}
+}
diff --git a/workspace-server/internal/provisioner/provisioner.go b/workspace-server/internal/provisioner/provisioner.go
index 498643447..60c1c827c 100644
--- a/workspace-server/internal/provisioner/provisioner.go
+++ b/workspace-server/internal/provisioner/provisioner.go
@@ -99,6 +99,7 @@ type WorkspaceConfig struct {
 	Runtime            string // "claude-code" (default), "codex", "hermes", "openclaw", etc.
 	InstanceType       string // Optional CP EC2 instance type override (SaaS only)
 	DiskGB             int32  // Optional CP root volume size override in GiB (SaaS only)
+	DataPersistence    string // internal#734: "persist"|"ephemeral"|"" — durable-data choice forwarded to CP (SaaS only)
 	Display            WorkspaceDisplayConfig
 	EnvVars            map[string]string // Additional env vars (API keys, etc.)
 	PlatformURL        string