diff --git a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Monitoring/AlarmSummary.razor b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Monitoring/AlarmSummary.razor
index 284486e2..b3bf3a26 100644
--- a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Monitoring/AlarmSummary.razor
+++ b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Monitoring/AlarmSummary.razor
@@ -11,6 +11,7 @@
 @inject IAlarmSummaryService AlarmSummaryService
 @inject ISiteRepository SiteRepository
 @inject ISiteAlarmLiveCache LiveAlarmCache
+@inject ZB.MOM.WW.ScadaBridge.CentralUI.Auth.SiteScopeService SiteScope
 
 <div class="container-fluid mt-3" data-test="alarm-summary">
     <div class="d-flex justify-content-between align-items-center mb-3">
@@ -275,7 +276,9 @@
     {
         try
         {
-            _sites = await SiteRepository.GetAllSitesAsync();
+            // Site scoping (CentralUI-002, arch-review P6-2): a scoped Deployment
+            // user may only watch live alarms for the sites they are permitted on.
+            _sites = await SiteScope.FilterSitesAsync(await SiteRepository.GetAllSitesAsync());
         }
         catch
         {
@@ -283,17 +286,36 @@
         }
     }
 
+    // _sites is already filtered, so membership IS the scope check — mirrors
+    // EventLogs.razor's SelectedSiteIsPermitted.
+    private bool IsSiteSelectionPermitted(int siteId) => _sites.Any(s => s.Id == siteId);
+
+    private void ClearSiteSelection()
+    {
+        _selectedSiteId = null;
+        _rows = Array.Empty<AlarmSummaryRow>();
+        _notReporting = Array.Empty<string>();
+        _rollup = new AlarmRollup(0, 0, 0, new Dictionary<AlarmKind, int>());
+        StopTimer();
+        DisposeLiveSubscription();
+    }
+
     private async Task OnSiteChangedAsync(ChangeEventArgs e)
     {
         var raw = e.Value?.ToString();
         if (string.IsNullOrEmpty(raw) || !int.TryParse(raw, out var siteId))
         {
-            _selectedSiteId = null;
-            _rows = Array.Empty<AlarmSummaryRow>();
-            _notReporting = Array.Empty<string>();
-            _rollup = new AlarmRollup(0, 0, 0, new Dictionary<AlarmKind, int>());
-            StopTimer();
-            DisposeLiveSubscription();
+            ClearSiteSelection();
+            return;
+        }
+
+        // Site scoping (CentralUI-002, arch-review P6-2): the dropdown is already
+        // filtered, but the selection must not be trusted on its own — re-check
+        // server-side so a forged onchange value naming an out-of-scope site is
+        // denied rather than merely hidden from the picker.
+        if (!IsSiteSelectionPermitted(siteId))
+        {
+            ClearSiteSelection();
             return;
         }
 
@@ -319,6 +341,16 @@
             return;
         }
 
+        // Site scoping (CentralUI-002, arch-review P6-2): re-check before every
+        // fetch, not just at selection time — defense in depth against
+        // _selectedSiteId ever being set by a path that skips OnSiteChangedAsync's
+        // check, so an out-of-scope site can never reach AlarmSummaryService.
+        if (!IsSiteSelectionPermitted(siteId))
+        {
+            ClearSiteSelection();
+            return;
+        }
+
         _loading = true;
         try
         {
diff --git a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryRenderTests.cs b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryRenderTests.cs
index 802ef522..8c513ba2 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryRenderTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryRenderTests.cs
@@ -67,6 +67,7 @@ public class AlarmSummaryRenderTests : BunitContext
         Services.AddSingleton(_siteRepo);
 
         Services.AddSingleton<ISiteAlarmLiveCache>(_liveCache);
+        Services.AddScoped<ZB.MOM.WW.ScadaBridge.CentralUI.Auth.SiteScopeService>();
 
         var claims = new[]
         {
@@ -278,6 +279,53 @@ public class AlarmSummaryRenderTests : BunitContext
         });
     }
 
+    // ── arch-review P6-2: site scoping (a scoped Deployer must not watch another
+    //    site's live alarms — the page was missed by the ad0100f2 scoping survey) ──
+
+    [Fact]
+    public void SiteScoping_ScopedDeploymentUser_SeesOnlyPermittedSiteInPicker()
+    {
+        var scopedUser = new ClaimsPrincipal(new ClaimsIdentity(new[]
+        {
+            new Claim(JwtTokenService.UsernameClaimType, "scoped"),
+            new Claim(JwtTokenService.RoleClaimType, "Deployer"),
+            new Claim(JwtTokenService.SiteIdClaimType, "1"), // Site 1 only
+        }, "TestAuth"));
+        Services.AddSingleton<AuthenticationStateProvider>(new TestAuthStateProvider(scopedUser));
+
+        var cut = Render<AlarmSummaryPage>();
+
+        var options = cut.FindAll("[data-test='alarm-summary-site'] option");
+        // "Select site…" placeholder + Site 1 only — Site 2 must not appear.
+        Assert.Equal(2, options.Count);
+        Assert.DoesNotContain("Site 2", cut.Markup);
+    }
+
+    [Fact]
+    public void SiteScoping_ForgedOutOfScopeSiteId_IsDeniedNotFetched()
+    {
+        // The picker never renders Site 2 for this user, but the change handler
+        // must independently reject an out-of-scope id arriving via any onchange
+        // value (e.g. a forged one, since Blazor Server processes the SignalR
+        // event server-side) rather than trusting it because it came through the
+        // <select> element.
+        var scopedUser = new ClaimsPrincipal(new ClaimsIdentity(new[]
+        {
+            new Claim(JwtTokenService.UsernameClaimType, "scoped"),
+            new Claim(JwtTokenService.RoleClaimType, "Deployer"),
+            new Claim(JwtTokenService.SiteIdClaimType, "1"), // Site 1 only
+        }, "TestAuth"));
+        Services.AddSingleton<AuthenticationStateProvider>(new TestAuthStateProvider(scopedUser));
+
+        var cut = Render<AlarmSummaryPage>();
+        cut.Find("[data-test='alarm-summary-site']").Change("2"); // out-of-scope, forged
+
+        // Denied server-side: no alarm table renders, selection resets to empty.
+        Assert.Empty(cut.FindAll("tr[data-test='alarm-summary-row']"));
+        Assert.NotNull(cut.Find("[data-test='alarm-summary-empty']"));
+        _summary.DidNotReceive().GetSiteAlarmsAsync(2, Arg.Any<CancellationToken>());
+    }
+
     // ── arch-review R2 N7: disposal guard on the live callback ─────────────────
 
     [Fact]
diff --git a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryVirtualizeTests.cs b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryVirtualizeTests.cs
index bd620106..3ca69a46 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryVirtualizeTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.CentralUI.Tests/Monitoring/AlarmSummaryVirtualizeTests.cs
@@ -49,6 +49,7 @@ public class AlarmSummaryVirtualizeTests : BunitContext
             }));
         Services.AddSingleton(_siteRepo);
         Services.AddSingleton<ISiteAlarmLiveCache>(new InertLiveCache());
+        Services.AddScoped<ZB.MOM.WW.ScadaBridge.CentralUI.Auth.SiteScopeService>();
 
         var claims = new[]
         {