fix: code-review follow-ups (watcher dispose race, revoke-enforcement tests, scan guard)

- ConsoleBypassWatcher: re-check _disposed after watcher.Start() — a Dispose()
  racing the background arm could leave an armed WMI subscription no code path
  could ever stop (leaked until process exit).
- SignalRContext: collapse rapid accessRevoked pushes into one restart via an
  in-flight guard — a second start() on a non-Disconnected connection throws
  and burns the retry budget.
- config/all: negative-cache managed ids a rescue scan proved missing (5 min
  TTL) — one stale grant (offboarded tenant) no longer makes every delegated
  config/all call pay a full table scan.
- DelegatedAdmin/TenantGroup functions: extract testable revoke-enforcement
  cores (RevokeCoreAsync, SetEnabledCoreAsync, UnassignCoreAsync,
  DeleteGroupCoreAsync, ValidateGrantRequest) and cover the security flows:
  404-on-missing-row writes no audit row and fires no disconnect; real
  revoke/disable/unassign/group-delete always cuts live streams; grant
  validation is fail-closed (GUID tenantId, recognized roles only).
- dashboard/page.tsx: drop unused next/link import left by the banner removal.

Tests: backend 3099 passed, web 557 passed, agent ConsoleBypassWatcher suite
passed, tsc clean.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/Agent/AutopilotMonitor.Agent.V2.Core/Monitoring/Telemetry/Security/ConsoleBypassWatcher.cs

@@ -136,6 +136,25 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Security
                 }
 
                 watcher.Start();
+
+                // Re-check after arming: Dispose() may have run between the lock release above and
+                // Start() — it then stopped a not-yet-armed watcher and this thread armed it right
+                // back, leaving a WMI subscription no code path could ever reach again. If disposal
+                // won that race, tear the watcher down here.
+                bool disposedDuringArm;
+                lock (_lock)
+                {
+                    disposedDuringArm = _disposed;
+                    if (disposedDuringArm) _startWatcher = null;
+                }
+                if (disposedDuringArm)
+                {
+                    try { watcher.EventArrived -= OnProcessStartTrace; } catch { }
+                    try { watcher.Stop(); } catch { }
+                    try { watcher.Dispose(); } catch { }
+                    return;
+                }
+
                 _logger.Info($"[ConsoleBypassWatcher] watching Win32_ProcessStartTrace for " +
                     $"{string.Join(", ", WatchedProcessNames)} (interactive-session + bare command line)");
             }

src/Backend/AutopilotMonitor.Functions.Tests/GetAllTenantConfigurationsFunctionTests.cs

@@ -129,4 +129,30 @@ public class GetAllTenantConfigurationsFunctionTests
     [Fact]
     public void DelegatedBareArrayView_Empty_Empty()
         => Assert.Empty(GetAllTenantConfigurationsFunction.DelegatedBareArrayView(new TenantConfiguration[0]));
+
+    [Fact]
+    public void MissingManagedIds_ReturnsOnlyIdsWithoutConfig_CaseInsensitive()
+    {
+        var configs = new List<TenantConfiguration>
+        {
+            new() { TenantId = TenantB.ToUpperInvariant() }, // case variant still counts as present
+        };
+
+        var missing = GetAllTenantConfigurationsFunction.MissingManagedIds(new[] { TenantB, TenantC }, configs);
+
+        var only = Assert.Single(missing);
+        Assert.Equal(TenantC, only);
+    }
+
+    [Fact]
+    public void MissingManagedIds_AllPresent_Empty()
+        => Assert.Empty(GetAllTenantConfigurationsFunction.MissingManagedIds(
+            new[] { TenantB },
+            new List<TenantConfiguration> { new() { TenantId = TenantB } }));
+
+    [Fact]
+    public void MissingConfigCacheKey_LowercasesId_SoCaseVariantsShareOneVerdict()
+        => Assert.Equal(
+            GetAllTenantConfigurationsFunction.MissingConfigCacheKey(TenantB),
+            GetAllTenantConfigurationsFunction.MissingConfigCacheKey(TenantB.ToUpperInvariant()));
 }

src/Backend/AutopilotMonitor.Functions.Tests/RevokeEnforcementTests.cs

@@ -0,0 +1,269 @@
+using AutopilotMonitor.Functions.Functions.Admin;
+using AutopilotMonitor.Functions.Services;
+using AutopilotMonitor.Shared;
+using AutopilotMonitor.Shared.DataAccess;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using Xunit;
+
+namespace AutopilotMonitor.Functions.Tests;
+
+/// <summary>
+/// Covers the SignalR revoke-enforcement cores of <see cref="DelegatedAdminManagementFunction"/> and
+/// <see cref="TenantGroupManagementFunction"/> (extracted seams — the HTTP entry points are intentionally
+/// not exercised, same rationale as <see cref="GetAllBlockedDevicesFunctionTests"/>). Locks in three
+/// security invariants: (1) a miss (no assignment row) neither audits nor disconnects — a typo must not
+/// write false customer-visible "access removed" rows while the real grant stays live; (2) a real
+/// revoke/disable/unassign/group-delete always cuts the affected UPN's live streams (group authorization
+/// is join-time only); (3) grant validation is fail-closed (GUID tenantId, recognized roles only).
+/// </summary>
+public class RevokeEnforcementTests
+{
+    private const string Upn = "MSP-Admin@Partner.Example";
+    private const string UpnLower = "msp-admin@partner.example";
+    private const string TenantA = "11111111-1111-1111-1111-111111111111";
+    private const string TenantB = "22222222-2222-2222-2222-222222222222";
+    private const string GroupId = "tpl-aaaaaaaa";
+
+    private static DelegatedAdminService BuildService(Mock<IAdminRepository> repo) =>
+        new(
+            repo.Object,
+            new StubTenantEntitlementService(AutopilotMonitor.Functions.Security.TenantEdition.Enterprise),
+            new MemoryCache(new MemoryCacheOptions()),
+            NullLogger<DelegatedAdminService>.Instance);
+
+    private static Mock<IMaintenanceRepository> BuildAuditRepo()
+    {
+        var audit = new Mock<IMaintenanceRepository>();
+        audit.Setup(a => a.LogAuditEntryAsync(
+                It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(),
+                It.IsAny<string>(), It.IsAny<string>(), It.IsAny<Dictionary<string, string>?>()))
+            .ReturnsAsync(true);
+        return audit;
+    }
+
+    private static void VerifyNoAudit(Mock<IMaintenanceRepository> audit) =>
+        audit.Verify(a => a.LogAuditEntryAsync(
+            It.IsAny<string>(), It.IsAny<string>(), It.IsAny<string>(),
+            It.IsAny<string>(), It.IsAny<string>(), It.IsAny<Dictionary<string, string>?>()), Times.Never);
+
+    private static (DelegatedAdminManagementFunction Fn, Mock<IAdminRepository> Repo,
+        Mock<IMaintenanceRepository> Audit, FakeSignalRNotificationService SignalR) BuildAdminFn()
+    {
+        var repo = new Mock<IAdminRepository>();
+        var audit = BuildAuditRepo();
+        var signalR = new FakeSignalRNotificationService();
+        var fn = new DelegatedAdminManagementFunction(
+            NullLogger<DelegatedAdminManagementFunction>.Instance, BuildService(repo), audit.Object, signalR);
+        return (fn, repo, audit, signalR);
+    }
+
+    private static (TenantGroupManagementFunction Fn, Mock<IAdminRepository> Repo,
+        Mock<IMaintenanceRepository> Audit, FakeSignalRNotificationService SignalR) BuildGroupFn()
+    {
+        var repo = new Mock<IAdminRepository>();
+        // Loose-mock defaults return a null Task — every repo read the flows touch needs a concrete setup.
+        repo.Setup(r => r.GetTenantGroupAsync(It.IsAny<string>())).ReturnsAsync((TenantGroup?)null);
+        repo.Setup(r => r.GetGroupAssignmentsForUpnAsync(It.IsAny<string>()))
+            .ReturnsAsync(new List<TenantGroupAssignment>());
+        repo.Setup(r => r.GetGroupAssigneesAsync(It.IsAny<string>()))
+            .ReturnsAsync(new List<TenantGroupAssignment>());
+        var audit = BuildAuditRepo();
+        var signalR = new FakeSignalRNotificationService();
+        var fn = new TenantGroupManagementFunction(
+            NullLogger<TenantGroupManagementFunction>.Instance, BuildService(repo), audit.Object, signalR);
+        return (fn, repo, audit, signalR);
+    }
+
+    // --- Delegated grant validation (fail-closed) ---
+
+    [Fact]
+    public void ValidateGrant_NullBody_Rejected()
+        => Assert.Equal("upn and tenantId are required",
+            DelegatedAdminManagementFunction.ValidateGrantRequest(null, out _));
+
+    [Theory]
+    [InlineData("", TenantA)]
+    [InlineData("   ", TenantA)]
+    [InlineData(Upn, "")]
+    public void ValidateGrant_MissingFields_Rejected(string upn, string tenantId)
+        => Assert.Equal("upn and tenantId are required",
+            DelegatedAdminManagementFunction.ValidateGrantRequest(
+                new GrantDelegatedAdminRequest { Upn = upn, TenantId = tenantId }, out _));
+
+    [Theory]
+    [InlineData("contoso.com")]
+    [InlineData("not-a-guid")]
+    [InlineData("11111111-1111-1111-1111")]
+    public void ValidateGrant_NonGuidTenantId_Rejected(string tenantId)
+        => Assert.Equal("a valid tenantId (GUID) is required",
+            DelegatedAdminManagementFunction.ValidateGrantRequest(
+                new GrantDelegatedAdminRequest { Upn = Upn, TenantId = tenantId }, out _));
+
+    [Fact]
+    public void ValidateGrant_UnknownRole_Rejected()
+    {
+        var error = DelegatedAdminManagementFunction.ValidateGrantRequest(
+            new GrantDelegatedAdminRequest { Upn = Upn, TenantId = TenantA, Role = "GlobalAdmin" }, out _);
+        Assert.NotNull(error);
+        Assert.Contains(Constants.DelegatedRoles.DelegatedReader, error);
+    }
+
+    [Fact]
+    public void ValidateGrant_EmptyRole_DefaultsToLeastPrivilegedReader()
+    {
+        Assert.Null(DelegatedAdminManagementFunction.ValidateGrantRequest(
+            new GrantDelegatedAdminRequest { Upn = Upn, TenantId = TenantA }, out var role));
+        Assert.Equal(Constants.DelegatedRoles.DelegatedReader, role);
+    }
+
+    [Fact]
+    public void ValidateGrant_ExplicitDelegatedAdmin_Accepted()
+    {
+        Assert.Null(DelegatedAdminManagementFunction.ValidateGrantRequest(
+            new GrantDelegatedAdminRequest { Upn = Upn, TenantId = TenantA, Role = Constants.DelegatedRoles.DelegatedAdmin },
+            out var role));
+        Assert.Equal(Constants.DelegatedRoles.DelegatedAdmin, role);
+    }
+
+    // --- Revoke: 404-on-missing-row vs. audit + disconnect ---
+
+    [Fact]
+    public async Task RevokeCore_MissingRow_NoAuditNoDisconnect()
+    {
+        var (fn, repo, audit, signalR) = BuildAdminFn();
+        repo.Setup(r => r.RemoveDelegatedAdminAsync(UpnLower, TenantA)).ReturnsAsync(false);
+
+        var removed = await fn.RevokeCoreAsync(Upn, TenantA, "ga@vendor.example");
+
+        Assert.False(removed);
+        VerifyNoAudit(audit);
+        Assert.Empty(signalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task RevokeCore_RemovedRow_AuditsAndDisconnectsLowercasedUpn()
+    {
+        var (fn, repo, audit, signalR) = BuildAdminFn();
+        repo.Setup(r => r.RemoveDelegatedAdminAsync(UpnLower, TenantA)).ReturnsAsync(true);
+
+        var removed = await fn.RevokeCoreAsync(Upn, TenantA, "ga@vendor.example");
+
+        Assert.True(removed);
+        // SignalR user ids are lowercased UPNs — a mixed-case route param must still hit the user's connections.
+        Assert.Equal(new[] { UpnLower }, signalR.DisconnectedUsers);
+        audit.Verify(a => a.LogAuditEntryAsync(
+            TenantA, "DELETE", "DelegatedAdmin", UpnLower, "ga@vendor.example", null), Times.Once);
+    }
+
+    // --- Disable is a revocation too; enable never disconnects ---
+
+    [Fact]
+    public async Task SetEnabledCore_MissingRow_NoAuditNoDisconnect()
+    {
+        var (fn, repo, audit, signalR) = BuildAdminFn();
+        repo.Setup(r => r.SetDelegatedAdminEnabledAsync(UpnLower, TenantA, false)).ReturnsAsync(false);
+
+        var ok = await fn.SetEnabledCoreAsync(Upn, TenantA, isEnabled: false, "ga@vendor.example");
+
+        Assert.False(ok);
+        VerifyNoAudit(audit);
+        Assert.Empty(signalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task SetEnabledCore_Disable_Disconnects()
+    {
+        var (fn, repo, _, signalR) = BuildAdminFn();
+        repo.Setup(r => r.SetDelegatedAdminEnabledAsync(UpnLower, TenantA, false)).ReturnsAsync(true);
+
+        var ok = await fn.SetEnabledCoreAsync(Upn, TenantA, isEnabled: false, "ga@vendor.example");
+
+        Assert.True(ok);
+        Assert.Equal(new[] { UpnLower }, signalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task SetEnabledCore_Enable_DoesNotDisconnect()
+    {
+        var (fn, repo, _, signalR) = BuildAdminFn();
+        repo.Setup(r => r.SetDelegatedAdminEnabledAsync(UpnLower, TenantA, true)).ReturnsAsync(true);
+
+        var ok = await fn.SetEnabledCoreAsync(Upn, TenantA, isEnabled: true, "ga@vendor.example");
+
+        Assert.True(ok);
+        Assert.Empty(signalR.DisconnectedUsers);
+    }
+
+    // --- Group unassign: 404-on-not-assigned vs. disconnect + per-tenant audit ---
+
+    [Fact]
+    public async Task UnassignCore_NotAssigned_NoAuditNoDisconnect()
+    {
+        var (fn, _, audit, signalR) = BuildGroupFn(); // default: no assignments for the UPN
+
+        var unassigned = await fn.UnassignCoreAsync(GroupId, Upn, "ga@vendor.example");
+
+        Assert.False(unassigned);
+        VerifyNoAudit(audit);
+        Assert.Empty(signalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task UnassignCore_Assigned_DisconnectsAndAuditsPerGroupTenant()
+    {
+        var (fn, repo, audit, signalR) = BuildGroupFn();
+        repo.Setup(r => r.GetTenantGroupAsync(GroupId)).ReturnsAsync(new TenantGroup
+        {
+            GroupId = GroupId,
+            Name = "MSP Customers",
+            TenantIds = new List<string> { TenantA, TenantB },
+            AssigneeCount = 1,
+        });
+        repo.Setup(r => r.GetGroupAssignmentsForUpnAsync(UpnLower))
+            .ReturnsAsync(new List<TenantGroupAssignment> { new() { Upn = UpnLower, GroupId = GroupId } });
+        repo.Setup(r => r.UnassignGroupAsync(UpnLower, GroupId)).ReturnsAsync(true);
+
+        var unassigned = await fn.UnassignCoreAsync(GroupId, Upn, "ga@vendor.example");
+
+        Assert.True(unassigned);
+        Assert.Equal(new[] { UpnLower }, signalR.DisconnectedUsers);
+        // Lost access is audited under EACH of the group's tenants (customer-visible trail).
+        audit.Verify(a => a.LogAuditEntryAsync(
+            TenantA, "DELETE", "DelegatedGroupAccess", UpnLower, "ga@vendor.example",
+            It.IsAny<Dictionary<string, string>?>()), Times.Once);
+        audit.Verify(a => a.LogAuditEntryAsync(
+            TenantB, "DELETE", "DelegatedGroupAccess", UpnLower, "ga@vendor.example",
+            It.IsAny<Dictionary<string, string>?>()), Times.Once);
+    }
+
+    // --- Group delete: every (former) assignee's streams are cut ---
+
+    [Fact]
+    public async Task DeleteGroupCore_DisconnectsEveryAssignee_AndAuditsPerTenant()
+    {
+        var (fn, repo, audit, signalR) = BuildGroupFn();
+        var assignees = new List<TenantGroupAssignment>
+        {
+            new() { Upn = "one@partner.example", GroupId = GroupId },
+            new() { Upn = "two@partner.example", GroupId = GroupId },
+        };
+        repo.Setup(r => r.GetTenantGroupAsync(GroupId)).ReturnsAsync(new TenantGroup
+        {
+            GroupId = GroupId,
+            Name = "MSP Customers",
+            TenantIds = new List<string> { TenantA },
+            AssigneeCount = assignees.Count,
+        });
+        repo.Setup(r => r.GetGroupAssigneesAsync(GroupId)).ReturnsAsync(assignees);
+        repo.Setup(r => r.DeleteTenantGroupAsync(GroupId)).ReturnsAsync(true);
+
+        await fn.DeleteGroupCoreAsync(GroupId, "ga@vendor.example");
+
+        Assert.Equal(new[] { "one@partner.example", "two@partner.example" }, signalR.DisconnectedUsers);
+        audit.Verify(a => a.LogAuditEntryAsync(
+            TenantA, "DELETE", "DelegatedGroupAccess", "*", "ga@vendor.example",
+            It.IsAny<Dictionary<string, string>?>()), Times.Once);
+    }
+}

src/Backend/AutopilotMonitor.Functions/Functions/Admin/DelegatedAdminManagementFunction.cs

@@ -64,19 +64,9 @@ public class DelegatedAdminManagementFunction
         var currentUpn = context.GetRequestContext().UserPrincipalName;
 
         var body = await req.ReadFromJsonAsync<GrantDelegatedAdminRequest>();
-        if (body == null || string.IsNullOrWhiteSpace(body.Upn) || string.IsNullOrWhiteSpace(body.TenantId))
-            return await Bad(req, "upn and tenantId are required");
-
-        // Mirror the tenant-group path: a mistyped tenantId must not create a garbage scope entry
-        // that pollutes the allow-list and seeds a per-tenant audit trail keyed on the typo.
-        if (!Guid.TryParse(body.TenantId, out _))
-            return await Bad(req, "a valid tenantId (GUID) is required");
-
-        // Default to the least-privileged role; reject anything we don't recognize (fail-closed) so a typo
-        // can never silently widen access.
-        var role = string.IsNullOrWhiteSpace(body.Role) ? Constants.DelegatedRoles.DelegatedReader : body.Role;
-        if (role != Constants.DelegatedRoles.DelegatedReader && role != Constants.DelegatedRoles.DelegatedAdmin)
-            return await Bad(req, $"role must be '{Constants.DelegatedRoles.DelegatedReader}' or '{Constants.DelegatedRoles.DelegatedAdmin}'");
+        var validationError = ValidateGrantRequest(body, out var role);
+        if (validationError != null)
+            return await Bad(req, validationError);
 
         // Edition note: TARGET tenants may be any edition — an MSP on Enterprise may manage Community
         // customers. The Enterprise requirement applies to the delegated admin's HOME tenant and is
@@ -84,7 +74,7 @@ public class DelegatedAdminManagementFunction
         // be checked here: at grant time only the UPN is known, and UPN-domain → tenant mapping is not
         // reliable (multi-domain tenants). Grants to non-Enterprise-homed admins are simply inert.
         var entry = await _delegatedAdminService.UpsertAsync(
-            body.Upn, body.TenantId, role,
+            body!.Upn, body.TenantId, role,
             Constants.DelegatedStatus.Active, Constants.DelegatedSource.OperatorGranted, currentUpn ?? "");
 
         await _maintenanceRepo.LogAuditEntryAsync(
@@ -112,10 +102,7 @@ public class DelegatedAdminManagementFunction
         string upn, string tenantId, FunctionContext context)
     {
         var currentUpn = context.GetRequestContext().UserPrincipalName;
-        // The service reports whether a row was actually deleted — a mistyped upn/tenantId must not
-        // 200 and write a false customer-visible "access removed" audit row while the real grant
-        // stays live (mirrors the tenant-group revoke semantics).
-        var removed = await _delegatedAdminService.RemoveAsync(upn, tenantId);
+        var removed = await RevokeCoreAsync(upn, tenantId, currentUpn);
         if (!removed)
         {
             var notFound = req.CreateResponse(HttpStatusCode.NotFound);
@@ -123,20 +110,34 @@ public class DelegatedAdminManagementFunction
             return notFound;
         }
 
-        await _maintenanceRepo.LogAuditEntryAsync(
-            tenantId.ToLowerInvariant(), "DELETE", "DelegatedAdmin", upn.ToLowerInvariant(), currentUpn ?? "");
-
-        // Enforcement: cut the revoked caller's already-joined live streams — group authorization is
-        // join-time only, so without this they keep receiving tenant telemetry until the connection drops.
-        await _signalRService.DisconnectUserAsync(upn.ToLowerInvariant());
-
-        _logger.LogInformation("Delegated revoke: {Upn} -> {TenantId} by {By}", upn, tenantId, currentUpn);
-
         var response = req.CreateResponse(HttpStatusCode.OK);
         await response.WriteAsJsonAsync(new { message = "Delegated assignment revoked" });
         return response;
     }
 
+    /// <summary>
+    /// Testable core of the revoke flow (no HTTP plumbing — see GetAllBlockedDevicesFunctionTests for the
+    /// convention). Returns false when no assignment row existed (caller 404s): a mistyped upn/tenantId
+    /// must not 200 and write a false customer-visible "access removed" audit row while the real grant
+    /// stays live (mirrors the tenant-group revoke semantics). On a real removal writes the audit entry
+    /// and cuts the revoked UPN's live streams — group authorization is join-time only, so without the
+    /// kick they keep receiving tenant telemetry until the connection drops.
+    /// </summary>
+    internal async Task<bool> RevokeCoreAsync(string upn, string tenantId, string? currentUpn)
+    {
+        var removed = await _delegatedAdminService.RemoveAsync(upn, tenantId);
+        if (!removed)
+            return false;
+
+        await _maintenanceRepo.LogAuditEntryAsync(
+            tenantId.ToLowerInvariant(), "DELETE", "DelegatedAdmin", upn.ToLowerInvariant(), currentUpn ?? "");
+
+        await _signalRService.DisconnectUserAsync(upn.ToLowerInvariant());
+
+        _logger.LogInformation("Delegated revoke: {Upn} -> {TenantId} by {By}", upn, tenantId, currentUpn);
+        return true;
+    }
+
     /// <summary>PATCH /api/global/delegated-admins/{upn}/{tenantId}/enable — re-enable a disabled assignment. GlobalAdminOnly.</summary>
     [Function("EnableDelegatedAdmin")]
     [Authorize]
@@ -157,7 +158,7 @@ public class DelegatedAdminManagementFunction
         HttpRequestData req, string upn, string tenantId, bool isEnabled, FunctionContext context)
     {
         var currentUpn = context.GetRequestContext().UserPrincipalName;
-        var ok = await _delegatedAdminService.SetEnabledAsync(upn, tenantId, isEnabled);
+        var ok = await SetEnabledCoreAsync(upn, tenantId, isEnabled, currentUpn);
         if (!ok)
         {
             var notFound = req.CreateResponse(HttpStatusCode.NotFound);
@@ -165,20 +166,56 @@ public class DelegatedAdminManagementFunction
             return notFound;
         }
 
+        var response = req.CreateResponse(HttpStatusCode.OK);
+        await response.WriteAsJsonAsync(new { message = isEnabled ? "Delegated assignment enabled" : "Delegated assignment disabled" });
+        return response;
+    }
+
+    /// <summary>
+    /// Testable core of enable/disable (no HTTP plumbing). Returns false when no assignment row
+    /// existed (caller 404s — no audit, no disconnect). Disable is a revocation too, so it cuts the
+    /// UPN's already-joined live streams (see <see cref="RevokeCoreAsync"/>); enable never disconnects.
+    /// </summary>
+    internal async Task<bool> SetEnabledCoreAsync(string upn, string tenantId, bool isEnabled, string? currentUpn)
+    {
+        var ok = await _delegatedAdminService.SetEnabledAsync(upn, tenantId, isEnabled);
+        if (!ok)
+            return false;
+
         await _maintenanceRepo.LogAuditEntryAsync(
             tenantId.ToLowerInvariant(), "UPDATE", "DelegatedAdmin", upn.ToLowerInvariant(), currentUpn ?? "",
             new Dictionary<string, string> { { "IsEnabled", isEnabled.ToString() } });
 
-        // Disable is a revocation too — cut already-joined live streams (see RevokeDelegatedAdmin).
         if (!isEnabled)
             await _signalRService.DisconnectUserAsync(upn.ToLowerInvariant());
 
         _logger.LogInformation("Delegated {Action}: {Upn} -> {TenantId} by {By}",
             isEnabled ? "enable" : "disable", upn, tenantId, currentUpn);
+        return true;
+    }
 
-        var response = req.CreateResponse(HttpStatusCode.OK);
-        await response.WriteAsJsonAsync(new { message = isEnabled ? "Delegated assignment enabled" : "Delegated assignment disabled" });
-        return response;
+    /// <summary>
+    /// Pure grant-request validation (testable seam). Returns the 400 error message, or null when valid —
+    /// then <paramref name="role"/> carries the effective role. A mistyped tenantId must not create a
+    /// garbage scope entry that pollutes the allow-list and seeds a per-tenant audit trail keyed on the
+    /// typo; the role defaults to least-privileged and unknown roles are rejected (fail-closed) so a typo
+    /// can never silently widen access.
+    /// </summary>
+    internal static string? ValidateGrantRequest(GrantDelegatedAdminRequest? body, out string role)
+    {
+        role = Constants.DelegatedRoles.DelegatedReader;
+
+        if (body == null || string.IsNullOrWhiteSpace(body.Upn) || string.IsNullOrWhiteSpace(body.TenantId))
+            return "upn and tenantId are required";
+
+        if (!Guid.TryParse(body.TenantId, out _))
+            return "a valid tenantId (GUID) is required";
+
+        role = string.IsNullOrWhiteSpace(body.Role) ? Constants.DelegatedRoles.DelegatedReader : body.Role!;
+        if (role != Constants.DelegatedRoles.DelegatedReader && role != Constants.DelegatedRoles.DelegatedAdmin)
+            return $"role must be '{Constants.DelegatedRoles.DelegatedReader}' or '{Constants.DelegatedRoles.DelegatedAdmin}'";
+
+        return null;
     }
 
     private static async Task<HttpResponseData> Bad(HttpRequestData req, string error)

src/Backend/AutopilotMonitor.Functions/Functions/Admin/TenantGroupManagementFunction.cs

@@ -112,15 +112,26 @@ public class TenantGroupManagementFunction
         string groupId, FunctionContext context)
     {
         var currentUpn = context.GetRequestContext().UserPrincipalName;
+        await DeleteGroupCoreAsync(groupId, currentUpn);
 
-        // Capture tenants + assignees BEFORE the cascade delete removes them, so we can audit the
-        // bulk access removal under each affected tenant and cut every assignee's live streams.
+        var response = req.CreateResponse(HttpStatusCode.OK);
+        await response.WriteAsJsonAsync(new { message = "Group deleted" });
+        return response;
+    }
+
+    /// <summary>
+    /// Testable core of the group cascade delete (no HTTP plumbing). Captures tenants + assignees
+    /// BEFORE the delete removes them, so the bulk access removal is audited under each affected
+    /// tenant and EVERY (former) assignee's live streams are cut — group authorization is join-time
+    /// only, so without the kick they keep receiving the managed tenants' telemetry until their
+    /// connection drops.
+    /// </summary>
+    internal async Task DeleteGroupCoreAsync(string groupId, string? currentUpn)
+    {
         var group = await _delegatedAdminService.GetGroupAsync(groupId);
         var assignees = await _delegatedAdminService.GetGroupAssigneesAsync(groupId);
         await _delegatedAdminService.DeleteGroupAsync(groupId);
 
-        // Enforcement: group authorization is join-time only — without the kick, every (former)
-        // assignee keeps receiving the managed tenants' live telemetry until their connection drops.
         foreach (var assignee in assignees)
             await _signalRService.DisconnectUserAsync(assignee.Upn);
 
@@ -137,10 +148,6 @@ public class TenantGroupManagementFunction
         }
 
         _logger.LogInformation("Tenant group deleted: {GroupId} by {By}", groupId, currentUpn);
-
-        var response = req.CreateResponse(HttpStatusCode.OK);
-        await response.WriteAsJsonAsync(new { message = "Group deleted" });
-        return response;
     }
 
     /// <summary>POST /api/global/tenant-groups/{groupId}/tenants — add a tenant. GlobalAdminOnly. Body: { "tenantId": "&lt;guid&gt;" }.</summary>
@@ -271,17 +278,31 @@ public class TenantGroupManagementFunction
         string groupId, string upn, FunctionContext context)
     {
         var currentUpn = context.GetRequestContext().UserPrincipalName;
+        var unassigned = await UnassignCoreAsync(groupId, upn, currentUpn);
+        if (!unassigned)
+            return await NotFound(req);
+
+        var response = req.CreateResponse(HttpStatusCode.OK);
+        await response.WriteAsJsonAsync(new { message = "Unassigned from group" });
+        return response;
+    }
+
+    /// <summary>
+    /// Testable core of the unassign flow (no HTTP plumbing). Returns false when the UPN was not
+    /// actually assigned (caller 404s) — so a mistyped UPN can't 200 and write false "access removed"
+    /// audit rows, and no disconnect fires. On a real unassign cuts the UPN's already-joined live
+    /// streams (join-time-only authz) and audits the lost access under each of the group's tenants.
+    /// </summary>
+    internal async Task<bool> UnassignCoreAsync(string groupId, string upn, string? currentUpn)
+    {
         var normalizedUpn = upn.ToLowerInvariant();
 
         // Read the group's tenants (unchanged by unassign) so we can audit the UPN's lost access per tenant.
         var group = await _delegatedAdminService.GetGroupAsync(groupId);
-        // The service returns false when the UPN was not actually assigned — so a mistyped UPN can't 200 and
-        // write false "access removed" audit rows. Only audit after a real unassign.
         var unassigned = await _delegatedAdminService.UnassignGroupAsync(normalizedUpn, groupId);
         if (!unassigned)
-            return await NotFound(req);
+            return false;
 
-        // Enforcement: cut the unassigned caller's already-joined live streams (join-time-only authz).
         await _signalRService.DisconnectUserAsync(normalizedUpn);
 
         if (group != null)
@@ -296,10 +317,7 @@ public class TenantGroupManagementFunction
         }
 
         _logger.LogInformation("Group {GroupId} unassigned from {Upn} by {By}", groupId, normalizedUpn, currentUpn);
-
-        var response = req.CreateResponse(HttpStatusCode.OK);
-        await response.WriteAsJsonAsync(new { message = "Unassigned from group" });
-        return response;
+        return true;
     }
 
     /// <summary>Logs one audit entry per tenant (the customer-visible "who can read my tenant" trail).</summary>

src/Backend/AutopilotMonitor.Functions/Functions/Config/GetAllTenantConfigurationsFunction.cs

@@ -10,6 +10,7 @@ using AutopilotMonitor.Functions.Services;
 using AutopilotMonitor.Shared.Models;
 using AutopilotMonitor.Shared.Pagination;
 using Microsoft.Azure.Functions.Worker;
+using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Azure.Functions.Worker.Http;
 using Microsoft.Extensions.Logging;
 
@@ -17,15 +18,23 @@ namespace AutopilotMonitor.Functions.Functions.Config
 {
     public class GetAllTenantConfigurationsFunction
     {
+        // TTL for the "this managed id has NO config row in any casing" verdict a rescue scan proved.
+        // Bounds how long a tenant onboarded moments after that scan stays absent from a delegated
+        // caller's config/all (matches the positive config cache TTL in TenantConfigurationService).
+        private static readonly TimeSpan MissingConfigNegativeCacheDuration = TimeSpan.FromMinutes(5);
+
         private readonly ILogger<GetAllTenantConfigurationsFunction> _logger;
         private readonly TenantConfigurationService _configService;
+        private readonly IMemoryCache _cache;
 
         public GetAllTenantConfigurationsFunction(
             ILogger<GetAllTenantConfigurationsFunction> logger,
-            TenantConfigurationService configService)
+            TenantConfigurationService configService,
+            IMemoryCache cache)
         {
             _logger = logger;
             _configService = configService;
+            _cache = cache;
         }
 
         [Function("GetAllTenantConfigurations")]
@@ -73,9 +82,21 @@ namespace AutopilotMonitor.Functions.Functions.Config
                     // (agent paths auto-create rows with the caller-supplied id verbatim) — the same caveat
                     // the delegated sessions fan-out handles case-insensitively. A point-read is exact-case,
                     // so any id it missed gets ONE scan+filter rescue pass (the pre-point-read behavior).
-                    // Only stale grants or case-variant rows pay for it; the common path stays read-bounded.
+                    // An id a previous scan already proved missing in ANY casing is negative-cached and
+                    // skipped for the TTL — otherwise a single stale grant (offboarded / never-onboarded
+                    // tenant) would make EVERY config/all call pay a full table scan.
                     if (subset.Count < managedIds.Count)
-                        subset = MergeRescuedConfigs(managedIds, subset, await _configService.GetAllConfigurationsAsync());
+                    {
+                        var unproven = MissingManagedIds(managedIds, subset)
+                            .Where(id => !_cache.TryGetValue(MissingConfigCacheKey(id), out _))
+                            .ToList();
+                        if (unproven.Count > 0)
+                        {
+                            subset = MergeRescuedConfigs(managedIds, subset, await _configService.GetAllConfigurationsAsync());
+                            foreach (var id in MissingManagedIds(unproven, subset))
+                                _cache.Set(MissingConfigCacheKey(id), true, MissingConfigNegativeCacheDuration);
+                        }
+                    }
                     _logger.LogInformation("GetAllTenantConfigurations (delegated subset, {Count} tenants) by {User}",
                         subset.Count, userIdentifier);
 
@@ -177,6 +198,23 @@ namespace AutopilotMonitor.Functions.Functions.Config
             IEnumerable<TenantConfiguration?> reads)
             => reads.Where(c => c != null).Select(c => c!).ToList();
 
+        /// <summary>
+        /// The managed ids not present (case-insensitively) in <paramref name="configs"/> — before the
+        /// rescue scan these are the point-read misses, after it the proven-missing ids to negative-cache.
+        /// Pure + testable.
+        /// </summary>
+        internal static List<string> MissingManagedIds(
+            IEnumerable<string> managedIds, IReadOnlyCollection<TenantConfiguration> configs)
+        {
+            var have = new HashSet<string>(configs.Select(c => c.TenantId), StringComparer.OrdinalIgnoreCase);
+            return managedIds.Where(id => !have.Contains(id)).ToList();
+        }
+
+        /// <summary>Negative-cache key for a managed id a rescue scan proved has no config row.
+        /// Lowercased so case variants of the same grant share one verdict.</summary>
+        internal static string MissingConfigCacheKey(string tenantId)
+            => $"tenant-config-missing:{tenantId.ToLowerInvariant()}";
+
         /// <summary>
         /// Case-variant rescue for managed ids the exact-case point-reads missed: from the full config scan,
         /// add every config whose TenantId matches a managed id case-insensitively and is not already in the

src/Web/autopilot-monitor-web/app/dashboard/page.tsx

@@ -1,7 +1,6 @@
 "use client";
 
 import { Suspense, useCallback, useEffect, useMemo, useRef, useState } from "react";
-import Link from "next/link";
 import { useRouter, useSearchParams } from "next/navigation";
 import { ProtectedRoute } from "../../components/ProtectedRoute";
 import { GlobalAdminBanner } from "@/components/GlobalAdminBanner";

src/Web/autopilot-monitor-web/contexts/SignalRContext.tsx

@@ -31,6 +31,9 @@ export function SignalRProvider({ children }: { children: React.ReactNode }) {
   const [joinedGroups, setJoinedGroups] = useState<string[]>([]);
   const retryCountRef = useRef(0);
   const retryTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+  // Collapses rapid successive accessRevoked pushes (one per revoked grant) into a single
+  // restart — a second start() on a non-Disconnected connection throws and burns the retry budget.
+  const revokeRestartInFlightRef = useRef(false);
   // Set in onreconnecting, read in onreconnected so we can report downtime as a measurement.
   const disconnectStartedAtRef = useRef<number | null>(null);
   const maxRetries = 3;
@@ -157,12 +160,20 @@ export function SignalRProvider({ children }: { children: React.ReactNode }) {
     // the next Connected transition — through the join endpoint, which re-runs authorization
     // against the fresh scope. Revoked groups 403; still-authorized streams recover automatically.
     newConnection.on('accessRevoked', async () => {
+      // Dropping an event that arrives mid-restart is safe: the rejoin after start() re-runs
+      // authorization against the CURRENT scope, which already reflects that later revoke.
+      if (revokeRestartInFlightRef.current) return;
+      revokeRestartInFlightRef.current = true;
       console.warn('[SignalR] accessRevoked received — restarting connection to re-authorize group memberships');
       trackEvent('signalr_access_revoked');
       try {
         await newConnection.stop();
       } catch { /* proceed to restart regardless */ }
-      startConnection();
+      try {
+        await startConnection();
+      } finally {
+        revokeRestartInFlightRef.current = false;
+      }
     });
 
     // Start as soon as the user is authenticated. The previous 2s setTimeout