diff --git a/fusion_plating/fusion_plating_shopfloor/static/src/js/tablet_lock.js b/fusion_plating/fusion_plating_shopfloor/static/src/js/tablet_lock.js
index ea6287bb..4909bc2a 100644
--- a/fusion_plating/fusion_plating_shopfloor/static/src/js/tablet_lock.js
+++ b/fusion_plating/fusion_plating_shopfloor/static/src/js/tablet_lock.js
@@ -34,6 +34,9 @@ export class FpTabletLock extends Component {
         this.techStore = useService("fp_shopfloor_tech_store");
         this.activity = useService("fp_shopfloor_activity");
         this.notification = useService("notification");
+        // Phase D: idle + ceiling timer for session_swap mode. Started
+        // once tiles bootstrap shows we're already on a tech session.
+        this.tabletSessionManager = useService("fp_tablet_session_manager");
 
         this.state = useState({
             tiles: [],
@@ -46,6 +49,10 @@ export class FpTabletLock extends Component {
             clockText: this._formatTime(new Date()),
             dateText: this._formatDate(new Date()),
             company: null,
+            // Phase D — feature flag + kiosk identity from bootstrap
+            sessionMode: "legacy",   // 'legacy' or 'session_swap'
+            kioskUid: null,
+            currentUid: null,
         });
 
         onMounted(async () => {
@@ -65,16 +72,33 @@ export class FpTabletLock extends Component {
                 this.state.clockText = this._formatTime(now);
                 this.state.dateText = this._formatDate(now);
             }, 60000);
+            // Session-swap mode: if we're already on a TECH session (uid
+            // != kiosk), start the idle/ceiling timer immediately. This
+            // handles the case where the page was reloaded after
+            // unlock_session minted the tech's session.
+            if (this.state.sessionMode === "session_swap"
+                && this.state.currentUid
+                && this.state.currentUid !== this.state.kioskUid) {
+                this.tabletSessionManager.beginSession();
+            }
         });
 
         onWillUnmount(() => {
             if (this._tick) clearInterval(this._tick);
             if (this._ping) clearInterval(this._ping);
             if (this._clockInterval) clearInterval(this._clockInterval);
+            this.tabletSessionManager.endSession();
         });
     }
 
     get isLocked() {
+        // SESSION-SWAP MODE: the BROWSER session itself tells us whether
+        // a tech is unlocked — current_uid != kiosk_uid means unlocked.
+        // LEGACY MODE: defer to the techStore client-side flag.
+        if (this.state.sessionMode === "session_swap") {
+            return !this.state.currentUid
+                || this.state.currentUid === this.state.kioskUid;
+        }
         return this.techStore.isLocked;
     }
 
@@ -85,6 +109,11 @@ export class FpTabletLock extends Component {
             const res = await rpc("/fp/tablet/tiles", { station_id: stationId });
             if (res && res.ok) {
                 this.state.company = res.company || null;
+                // Phase D — capture session_mode + kiosk/current uids so
+                // unlock() / isLocked / handOff can branch on mode.
+                this.state.sessionMode = res.tablet_session_mode || "legacy";
+                this.state.kioskUid = res.kiosk_uid || null;
+                this.state.currentUid = res.current_uid || null;
                 // Decorate each tile with an animation-delay (50ms staggered,
                 // capped at 300ms so the screen doesn't take 3s to settle on
                 // shops with 20+ operators).
@@ -127,6 +156,25 @@ export class FpTabletLock extends Component {
 
     async unlock(pin) {
         try {
+            // SESSION-SWAP MODE: call the new endpoint, then reload the
+            // page so the browser re-bootstraps under the tech's session.
+            if (this.state.sessionMode === "session_swap") {
+                const res = await rpc("/fp/tablet/unlock_session", {
+                    user_id: this.state.selectedTileUserId,
+                    pin,
+                });
+                if (res && res.ok) {
+                    // Cookie has swapped. Reload so OWL/services re-init
+                    // under the new (tech) session. The session manager
+                    // (Task D1) picks up on the next page load.
+                    window.location.reload();
+                    // Return a pending state so the caller doesn't try to
+                    // navigate while we're tearing down.
+                    return { ok: true, reloading: true };
+                }
+                return { ok: false, error: (res && res.error) || "Unlock failed" };
+            }
+            // LEGACY MODE: existing /fp/tablet/unlock path
             const res = await rpc("/fp/tablet/unlock", {
                 user_id: this.state.selectedTileUserId,
                 pin,
@@ -148,6 +196,13 @@ export class FpTabletLock extends Component {
     }
 
     handOff() {
+        // SESSION-SWAP MODE: the server destroys the tech session, then
+        // we reload to re-bootstrap as the kiosk.
+        if (this.state.sessionMode === "session_swap") {
+            this.tabletSessionManager.lockBack("manual");
+            return;
+        }
+        // LEGACY MODE: client-side state flip only.
         this.techStore.lock();
         this.state.selectedTileUserId = null;
         this.state.idleSecondsRemaining = null;
diff --git a/fusion_plating/fusion_plating_shopfloor/static/src/xml/tablet_lock.xml b/fusion_plating/fusion_plating_shopfloor/static/src/xml/tablet_lock.xml
index e9626953..12d3c549 100644
--- a/fusion_plating/fusion_plating_shopfloor/static/src/xml/tablet_lock.xml
+++ b/fusion_plating/fusion_plating_shopfloor/static/src/xml/tablet_lock.xml
@@ -75,6 +75,20 @@
             <t t-slot="default"/>
             <FpIdleWarning t-if="state.idleSecondsRemaining !== null"
                            secondsRemaining="state.idleSecondsRemaining"/>
+            <!-- Phase D: floating Hand-Off button for session_swap mode.
+                 In legacy mode the wrapper components (landing/workspace/
+                 manager) own their own Hand-Off buttons that hit
+                 techStore.lock(). In session_swap mode those become
+                 no-ops (techStore isn't the source of truth anymore),
+                 so we render a tablet_lock-owned button that calls
+                 our own handOff() which routes through the session
+                 manager + page reload. -->
+            <button t-if="state.sessionMode === 'session_swap'"
+                    class="o_fp_lock_handoff_btn btn btn-warning"
+                    t-on-click="handOff"
+                    title="Lock the tablet for the next operator">
+                <i class="fa fa-lock"/> Hand Off
+            </button>
         </t>
     </t>