fix(security): ConsoleBypassWatcher mirrors cmd.exe first-switch-wins parsing — only a leading /c classifies as scripted; a /c inside a /k payload (cmd /k rem /c, cmd /k "title /c") no longer silences a persistent interactive console, which is surfaced as interactive_console_with_command (low)

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

src/Agent/AutopilotMonitor.Agent.V2.Core.Tests/Monitoring/Security/ConsoleBypassWatcherTests.cs

@@ -94,6 +94,22 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Security
             Assert.Equal("interactive_console_with_command", info.Classification);
         }
 
+        [Theory]
+        [InlineData(@"cmd /k rem /c")]
+        [InlineData(@"cmd.exe /k ""title /c""")]
+        public void Cmd_k_with_slash_c_in_payload_is_not_demoted_to_scripted(string commandLine)
+        {
+            // cmd.exe honors only the FIRST /c-or-/k switch; a '/c' inside the /k payload is inert, so
+            // the console is a persistent human-usable shell and must still be surfaced (low confidence).
+            using var rig = new Rig(Probe(commandLine));
+
+            rig.Sut.HandleStart(2223, 1, sessionId: 1, ownerSidHint: null, detectedVia: "process_start_trace");
+
+            var info = Assert.Single(rig.Detected);
+            Assert.Equal("low", info.Confidence);
+            Assert.Equal("interactive_console_with_command", info.Classification);
+        }
+
         [Fact]
         public void Instant_close_unreadable_commandline_raises_low_confidence()
         {
@@ -146,6 +162,10 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Security
         [InlineData(2, @"C:\x\cmd.exe /K bar", "InteractiveWithCommand")] // L12: /k stays interactive
         [InlineData(1, @"cmd.exe /k whoami", "InteractiveWithCommand")]   // technician-planted shell
         [InlineData(1, @"cmd.exe /d/q/c exit 9", "Ignore")]            // combined run-and-exit wins
+        [InlineData(1, @"cmd /k rem /c", "InteractiveWithCommand")]     // cmd.exe honors the FIRST switch: /k stays interactive
+        [InlineData(1, @"cmd.exe /k ""title /c""", "InteractiveWithCommand")] // /c inside the /k payload is not a switch
+        [InlineData(1, @"cmd /k /c", "InteractiveWithCommand")]         // /c after /k is just the /k payload
+        [InlineData(1, @"cmd.exe /c cmd /k", "Ignore")]                 // first switch /c wins the other way round
         public void Classify_maps_session_and_commandline(int sessionId, string? commandLine, string expected)
         {
             Assert.Equal(expected, ConsoleBypassWatcher.Classify(sessionId, commandLine).ToString());
@@ -165,6 +185,8 @@ namespace AutopilotMonitor.Agent.V2.Core.Tests.Monitoring.Security
         [InlineData(@"cmd.exe /k", false)]                       // L12: /k leaves an interactive shell
         [InlineData(@"cmd.exe /d/q/c exit 9", true)]             // combined switches — the field case
         [InlineData(@"cmd.exe /D/Q/K stay", false)]              // L12: run-and-stay is not scripted
+        [InlineData(@"cmd.exe /k rem /c", false)]                // first switch /k wins — payload /c is inert
+        [InlineData(@"cmd.exe /c rem /k", true)]                 // first switch /c wins
         [InlineData(@"""C:\WINDOWS\system32\cmd.exe"" /c ""x.bat""", true)]
         public void HasScriptArgument_detects_run_command_switch(string commandLine, bool expected)
         {

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

@@ -47,17 +47,26 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Security
         /// </summary>
         internal static readonly string[] WatchedProcessNames = { "cmd.exe" };
 
-        // /c turns the shell into a one-shot scripted invocation (install/script) — ignored. Matched
-        // as a token anywhere in the ARGUMENTS (the executable path is stripped first) so combined
-        // switches like /d/q/c are caught too.
-        private static readonly Regex RunAndExitSwitchRegex =
-            new Regex(@"/c\b", RegexOptions.IgnoreCase | RegexOptions.Compiled);
-
+        // cmd.exe honors only the FIRST of /c or /k; everything after that switch is the command
+        // payload. /c turns the shell into a one-shot scripted invocation (install/script) — ignored.
         // /k runs its command and then STAYS interactive (L12) — unlike /c this leaves a shell a
         // human can type into (e.g. a technician-planted `cmd /k whoami`), so it is surfaced as a
-        // low-confidence interactive console instead of being silently ignored.
-        private static readonly Regex RunAndStaySwitchRegex =
-            new Regex(@"/k\b", RegexOptions.IgnoreCase | RegexOptions.Compiled);
+        // low-confidence interactive console instead of being silently ignored. One ordered scan over
+        // the ARGUMENTS (executable path stripped first) finds the first switch token, so combined
+        // switches like /d/q/c are caught and a `/c` inside a /k payload (`cmd /k rem /c`) can no
+        // longer demote an interactive shell to a scripted one.
+        private static readonly Regex FirstRunSwitchRegex =
+            new Regex(@"/(?<sw>[ck])\b", RegexOptions.IgnoreCase | RegexOptions.Compiled);
+
+        private enum RunSwitch { None, RunAndExit, RunAndStay }
+
+        /// <summary>The first <c>/c</c> or <c>/k</c> switch in the argument tail — cmd.exe precedence.</summary>
+        private static RunSwitch FirstRunSwitch(string arguments)
+        {
+            var m = FirstRunSwitchRegex.Match(arguments);
+            if (!m.Success) return RunSwitch.None;
+            return char.ToLowerInvariant(m.Groups["sw"].Value[0]) == 'c' ? RunSwitch.RunAndExit : RunSwitch.RunAndStay;
+        }
 
         private readonly AgentLogger _logger;
         private readonly Func<int, ProcessProbe?> _processProbe;
@@ -282,20 +291,23 @@ namespace AutopilotMonitor.Agent.V2.Core.Monitoring.Telemetry.Security
         {
             if (sessionId == 0) return ConsoleVerdict.Ignore;
             if (commandLine == null) return ConsoleVerdict.UnclassifiedInteractive;
-            var arguments = StripExecutable(commandLine);
-            if (RunAndExitSwitchRegex.IsMatch(arguments)) return ConsoleVerdict.Ignore;
-            if (RunAndStaySwitchRegex.IsMatch(arguments)) return ConsoleVerdict.InteractiveWithCommand;
-            return ConsoleVerdict.InteractiveConsole;
+            switch (FirstRunSwitch(StripExecutable(commandLine)))
+            {
+                case RunSwitch.RunAndExit: return ConsoleVerdict.Ignore;
+                case RunSwitch.RunAndStay: return ConsoleVerdict.InteractiveWithCommand;
+                default: return ConsoleVerdict.InteractiveConsole;
+            }
         }
 
-        /// <summary>True when the command line carries a <c>/c</c> run-and-exit switch (a scripted
-        /// invocation), false for a bare interactive shell or a <c>/k</c> run-and-stay shell. The
-        /// executable token is stripped first so a path can never spoof a switch, and switches may
-        /// be combined (e.g. <c>cmd /d/q/c exit 9</c>).</summary>
+        /// <summary>True when the FIRST <c>/c</c>-or-<c>/k</c> switch on the command line is <c>/c</c>
+        /// (a scripted run-and-exit invocation, mirroring cmd.exe precedence), false for a bare
+        /// interactive shell or a <c>/k</c> run-and-stay shell — even one whose payload contains a
+        /// later <c>/c</c>. The executable token is stripped first so a path can never spoof a
+        /// switch, and switches may be combined (e.g. <c>cmd /d/q/c exit 9</c>).</summary>
         internal static bool HasScriptArgument(string commandLine)
         {
             if (string.IsNullOrEmpty(commandLine)) return false;
-            return RunAndExitSwitchRegex.IsMatch(StripExecutable(commandLine));
+            return FirstRunSwitch(StripExecutable(commandLine)) == RunSwitch.RunAndExit;
         }
 
         /// <summary>Returns the command line with the leading executable token (quoted or

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

@@ -6,6 +6,11 @@ using AutopilotMonitor.Shared.Models;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.Logging;
 using Moq;
+using System.Net;
+using System.Security.Claims;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Azure.Functions.Worker.Http;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace AutopilotMonitor.Functions.Tests;
 
@@ -26,6 +31,7 @@ public class AuthFunctionSideEffectTests
     private readonly Mock<GlobalNotificationService> _globalNotificationMock;
     private readonly Mock<IMetricsRepository> _metricsRepoMock;
     private readonly Mock<AutopilotMonitor.Functions.Services.Activation.ITenantAutoApproveEnqueuer> _autoApproveEnqueuerMock;
+    private readonly FakeSignalRNotificationService _signalR;
     private readonly AuthFunction _sut;
 
     public AuthFunctionSideEffectTests()
@@ -82,6 +88,7 @@ public class AuthFunctionSideEffectTests
         _metricsRepoMock = new Mock<IMetricsRepository>();
         _autoApproveEnqueuerMock = new Mock<AutopilotMonitor.Functions.Services.Activation.ITenantAutoApproveEnqueuer>();
 
+        _signalR = new FakeSignalRNotificationService();
         _sut = new AuthFunction(
             Mock.Of<ILogger<AuthFunction>>(),
             globalAdminMock.Object,
@@ -98,7 +105,8 @@ public class AuthFunctionSideEffectTests
                 new Microsoft.Extensions.Configuration.ConfigurationBuilder().Build(),
                 Mock.Of<ILogger<AutopilotMonitor.Functions.Security.EntraAppRegistry>>()),
             new Mock<AdminIdentityResolver>(
-                _metricsRepoMock.Object, _tenantConfigMock.Object, Mock.Of<ILogger<AdminIdentityResolver>>()) { CallBase = false }.Object);
+                _metricsRepoMock.Object, _tenantConfigMock.Object, Mock.Of<ILogger<AdminIdentityResolver>>()) { CallBase = false }.Object,
+            _signalR);
 
         // Default: all fire-and-forget calls succeed
         _tenantConfigMock
@@ -123,6 +131,63 @@ public class AuthFunctionSideEffectTests
     // HandleNewTenantDomainAsync
     // -------------------------------------------------------------------------
 
+    // ── RemoveGlobalAdmin cuts live SignalR streams (join-time-only group authz) ──
+
+    [Fact]
+    public async Task RemoveGlobalAdmin_DisconnectsTheRemovedAdminsSignalRConnections()
+    {
+        var (req, ctx) = BuildAuthenticatedRequest(callerUpn: "operator@contoso.com");
+
+        var response = await _sut.RemoveGlobalAdmin(req, "Removed@Contoso.com", ctx);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        Assert.Equal(new[] { "removed@contoso.com" }, _signalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task RemoveGlobalAdmin_SelfRemovalIsRejectedWithoutDisconnect()
+    {
+        var (req, ctx) = BuildAuthenticatedRequest(callerUpn: "operator@contoso.com");
+
+        var response = await _sut.RemoveGlobalAdmin(req, "operator@contoso.com", ctx);
+
+        Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+        Assert.Empty(_signalR.DisconnectedUsers);
+    }
+
+    private static (HttpRequestData Req, FunctionContext Ctx) BuildAuthenticatedRequest(string callerUpn)
+    {
+        var services = new ServiceCollection();
+        services.AddOptions();
+        services.Configure<WorkerOptions>(o => o.Serializer =
+            new Azure.Core.Serialization.JsonObjectSerializer(
+                new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web)));
+        var provider = services.BuildServiceProvider();
+
+        var principal = new ClaimsPrincipal(new ClaimsIdentity(
+            new[] { new Claim("preferred_username", callerUpn) }, "test"));
+
+        var context = new Mock<FunctionContext>();
+        context.SetupGet(c => c.Items).Returns(
+            new Dictionary<object, object> { ["ClaimsPrincipal"] = principal });
+        context.SetupGet(c => c.InstanceServices).Returns(provider);
+
+        var req = new Mock<HttpRequestData>(context.Object);
+        req.SetupGet(r => r.Headers).Returns(new HttpHeadersCollection());
+        req.SetupGet(r => r.Body).Returns(new MemoryStream());
+        req.Setup(r => r.CreateResponse()).Returns(() => new FakeHttpResponseData(context.Object));
+        return (req.Object, context.Object);
+    }
+
+    private sealed class FakeHttpResponseData : HttpResponseData
+    {
+        public FakeHttpResponseData(FunctionContext context) : base(context) { }
+        public override HttpStatusCode StatusCode { get; set; } = HttpStatusCode.OK;
+        public override HttpHeadersCollection Headers { get; set; } = new();
+        public override Stream Body { get; set; } = new MemoryStream();
+        public override HttpCookies Cookies { get; } = new Mock<HttpCookies>().Object;
+    }
+
     [Fact]
     public async Task HandleNewTenantDomain_WhenUpnDomainIsNotAHostName_DoesNotSeed()
     {

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

@@ -133,12 +133,64 @@ public class TenantAdminManagementFunctionTests
             TenantId, CallerUpn, Constants.TenantRoles.Admin, true), Times.Once);
     }
 
+    // ── revocation cuts live SignalR streams (join-time-only group authz) ────
+
+    [Fact]
+    public async Task Remove_disconnects_the_removed_members_signalr_connections()
+    {
+        var h = BuildHarness();
+        var (req, ctx) = BuildRequest(new { });
+
+        var response = await h.Function.RemoveTenantAdmin(req, TenantId, "Demoted@Contoso.com", ctx);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        Assert.Equal(new[] { "demoted@contoso.com" }, h.SignalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task Disable_disconnects_the_disabled_members_signalr_connections()
+    {
+        var h = BuildHarness();
+        var (req, ctx) = BuildRequest(new { });
+
+        var response = await h.Function.DisableTenantAdmin(req, TenantId, "Demoted@Contoso.com", ctx);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        Assert.Equal(new[] { "demoted@contoso.com" }, h.SignalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task Enable_does_not_disconnect()
+    {
+        var h = BuildHarness();
+        var (req, ctx) = BuildRequest(new { });
+
+        await h.Function.EnableTenantAdmin(req, TenantId, "user@contoso.com", ctx);
+
+        Assert.Empty(h.SignalR.DisconnectedUsers);
+    }
+
+    [Fact]
+    public async Task Demotion_below_admin_disconnects_but_promotion_to_admin_does_not()
+    {
+        var h = BuildHarness();
+
+        var (demote, ctx1) = BuildRequest(new { role = "viewer", canManageBootstrapTokens = false });
+        await h.Function.UpdateMemberPermissions(demote, TenantId, "User@Contoso.com", ctx1);
+        Assert.Equal(new[] { "user@contoso.com" }, h.SignalR.DisconnectedUsers);
+
+        var (promote, ctx2) = BuildRequest(new { role = "admin", canManageBootstrapTokens = false });
+        await h.Function.UpdateMemberPermissions(promote, TenantId, "other@contoso.com", ctx2);
+        Assert.Equal(new[] { "user@contoso.com" }, h.SignalR.DisconnectedUsers);
+    }
+
     // ── harness ─────────────────────────────────────────────────────────────
 
     private sealed class Harness
     {
         public TenantAdminManagementFunction Function = default!;
         public Mock<IAdminRepository> AdminRepo = default!;
+        public FakeSignalRNotificationService SignalR = default!;
     }
 
     private static Harness BuildHarness()
@@ -157,12 +209,14 @@ public class TenantAdminManagementFunctionTests
             NullLogger<TenantAdminsService>.Instance);
 
         var maintenanceRepo = new Mock<IMaintenanceRepository>(MockBehavior.Loose);
+        var signalR = new FakeSignalRNotificationService();
 
         return new Harness
         {
             Function = new TenantAdminManagementFunction(
-                NullLogger<TenantAdminManagementFunction>.Instance, service, maintenanceRepo.Object),
+                NullLogger<TenantAdminManagementFunction>.Instance, service, maintenanceRepo.Object, signalR),
             AdminRepo = adminRepo,
+            SignalR = signalR,
         };
     }
 

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

@@ -680,6 +680,51 @@ public class TenantConfigPatchServiceTests
         Assert.Equal(schema.Count, schema.Select(f => f.Name).Distinct().Count());
     }
 
+    /// <summary>
+    /// The full-model PUT (config/{tenantId}) must honour the same deny-list as the field
+    /// patch: a client body carrying ProDowngradedUtc (retention-downgrade grace anchor),
+    /// OnboardedAt, DomainName, plan/trial or provenance fields must not change the stored
+    /// values. Driven by the deny-list itself so a new denied field is covered automatically.
+    /// </summary>
+    [Fact]
+    public void PreserveDeniedFields_OverwritesEveryDeniedModelPropertyFromStored()
+    {
+        var props = typeof(TenantConfiguration)
+            .GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance)
+            .Where(p => p.CanWrite && TenantConfigPatchService.BaseDeniedFields.Contains(p.Name))
+            .ToList();
+        Assert.Contains(props, p => p.Name == "ProDowngradedUtc");
+        Assert.Contains(props, p => p.Name == "OnboardedAt");
+        Assert.Contains(props, p => p.Name == "DomainName");
+
+        var stored = new TenantConfiguration { TenantId = "t1" };
+        var incoming = new TenantConfiguration { TenantId = "t1" };
+        foreach (var p in props)
+        {
+            p.SetValue(stored, Distinct(p.PropertyType, 1));
+            p.SetValue(incoming, Distinct(p.PropertyType, 2));
+            Assert.NotEqual(p.GetValue(stored), p.GetValue(incoming));
+        }
+
+        TenantConfigPatchService.PreserveDeniedFields(incoming, stored);
+
+        foreach (var p in props)
+            Assert.Equal(p.GetValue(stored), p.GetValue(incoming));
+    }
+
+    private static object Distinct(Type t, int seed)
+    {
+        var u = Nullable.GetUnderlyingType(t) ?? t;
+        if (u == typeof(string)) return $"value-{seed}";
+        if (u == typeof(bool)) return seed % 2 == 0;
+        if (u == typeof(int)) return seed;
+        if (u == typeof(long)) return (long)seed;
+        if (u == typeof(DateTime)) return new DateTime(2026, 1, seed, 0, 0, 0, DateTimeKind.Utc);
+        if (u == typeof(DateTimeOffset)) return new DateTimeOffset(2026, 1, seed, 0, 0, 0, TimeSpan.Zero);
+        if (u.IsEnum) return Enum.GetValues(u).GetValue(seed % Enum.GetValues(u).Length)!;
+        throw new NotSupportedException($"Add a Distinct() case for {u.Name}");
+    }
+
     [Fact]
     public void FieldsSchema_DeniedFields_MatchThePatchDenyList()
     {

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

@@ -18,17 +18,31 @@ public class TenantAdminManagementFunction
     private readonly ILogger<TenantAdminManagementFunction> _logger;
     private readonly TenantAdminsService _tenantAdminsService;
     private readonly IMaintenanceRepository _maintenanceRepo;
+    private readonly ISignalRNotificationService _signalRService;
 
     public TenantAdminManagementFunction(
         ILogger<TenantAdminManagementFunction> logger,
         TenantAdminsService tenantAdminsService,
-        IMaintenanceRepository maintenanceRepo)
+        IMaintenanceRepository maintenanceRepo,
+        ISignalRNotificationService signalRService)
     {
         _logger = logger;
         _tenantAdminsService = tenantAdminsService;
         _maintenanceRepo = maintenanceRepo;
+        _signalRService = signalRService;
     }
 
+    /// <summary>
+    /// SignalR group authorization is evaluated only at join time (SignalRAddToGroupFunction), so a
+    /// member whose role was removed, disabled or lowered would keep their already-joined
+    /// 'tenant-{tid}' broadcast, notify-group and session-group streams until the socket drops.
+    /// Cutting the UPN's connections (negotiate binds userId = lowercased UPN) forces a reconnect that
+    /// re-runs the join gates against the new role. Coarse by design — a still-authorized client
+    /// simply reconnects — and mirrors the delegated-admin / tenant-group revoke paths.
+    /// </summary>
+    private Task CutLiveStreamsAsync(string adminUpn) =>
+        _signalRService.DisconnectUserAsync(adminUpn.ToLowerInvariant());
+
     /// <summary>
     /// GET /api/tenants/{tenantId}/admins
     /// Gets all admins for a tenant
@@ -158,6 +172,8 @@ public class TenantAdminManagementFunction
             upn!
         );
 
+        await CutLiveStreamsAsync(adminUpn);
+
         _logger.LogInformation($"Tenant Admin removed: {adminUpn} from tenant {requestCtx.TargetTenantId} by {upn}");
 
         var response = req.CreateResponse(HttpStatusCode.OK);
@@ -194,6 +210,8 @@ public class TenantAdminManagementFunction
             new Dictionary<string, string> { { "Action", "Disable" } }
         );
 
+        await CutLiveStreamsAsync(adminUpn);
+
         _logger.LogInformation($"Tenant Admin disabled: {adminUpn} for tenant {requestCtx.TargetTenantId} by {upn}");
 
         var response = req.CreateResponse(HttpStatusCode.OK);
@@ -308,6 +326,10 @@ public class TenantAdminManagementFunction
             }
         );
 
+        // Only Admin holds the admin-tier notify group; any other target role may have lost it.
+        if (role != AutopilotMonitor.Shared.Constants.TenantRoles.Admin)
+            await CutLiveStreamsAsync(adminUpn);
+
         _logger.LogInformation("Member permissions updated: {AdminUpn} -> role={Role} in tenant {TenantId} by {Upn}", adminUpn, role, requestCtx.TargetTenantId, upn);
 
         var response = req.CreateResponse(HttpStatusCode.OK);

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

@@ -110,11 +110,15 @@ namespace AutopilotMonitor.Functions.Functions.Config
                 // admins are served the FULL config so this is normally a no-op for them.)
                 config.RestoreRedactedSecretsFrom(existingConfig);
 
-                // DomainName is tenant identity: seeded once from the first login's UPN (AuthFunction)
-                // and never client-writable — for ANY caller, GA included — mirroring the patch flow
-                // ("identity — never writable"). Without this preserve the full-model PUT persisted an
-                // arbitrary string here, which is rendered into the welcome/farewell mails.
-                config.DomainName = existingConfig.DomainName;
+                // System-owned fields are never client-writable — for ANY caller, GA included:
+                // identity (DomainName, seeded once from the first login's UPN), onboarding/auth
+                // provenance (OnboardedAt/OnboardedBy/LastAuthClientId*), app-reg homing
+                // (HomedAppClientId — the 2026-07-31 stale-round-trip incident), and plan/trial/
+                // downgrade state (PlanTier/Trial*/ProDowngradedUtc — mutable only via the plan
+                // and trial endpoints; a client-supplied ProDowngradedUtc would refresh the
+                // retention-downgrade grace anchor indefinitely). The set is the PATCH endpoint's
+                // BaseDeniedFields, so the two write paths cannot drift.
+                TenantConfigPatchService.PreserveDeniedFields(config, existingConfig);
 
                 // Shared model validation (rate limits, contact address, webhook/Teams SSRF, custom
                 // headers, notification channels, diagnostics SAS, retention cap) — single source
@@ -164,26 +168,6 @@ namespace AutopilotMonitor.Functions.Functions.Config
                     config.DisabledUntil = existingConfig.DisabledUntil;
                 }
 
-                // App-reg homing is IMMUTABLE via the generic PUT — for ALL callers, GA included.
-                // The only writers are the consent-driven auto-flip and POST config/{tenantId}/
-                // app-homing (AppHomingFunction). Prod incident 2026-07-31 18:03Z: the consent
-                // auto-flip landed, and 600ms later the frontend's routine "persist validation
-                // toggle" PUT — round-tripping a config loaded BEFORE the flip — silently reverted
-                // the homing to legacy, because a GA caller's stale null was indistinguishable
-                // from an intentional revert. A full-model PUT can never carry that intent.
-                config.HomedAppClientId = existingConfig.HomedAppClientId;
-
-                // Last-seen auth provenance is system-written (AuthFunction) — never via PUT,
-                // for ANY caller: a round-tripped stale view must not rewind the observability.
-                config.LastAuthClientId = existingConfig.LastAuthClientId;
-                config.LastAuthClientIdSince = existingConfig.LastAuthClientIdSince;
-
-                // OnboardedBy is system-written once at first login (AuthFunction) and immutable
-                // after that — never via PUT, for ANY caller: a revoke → re-approve cycle
-                // auto-promotes whatever UPN is stored here, so a client-supplied value could
-                // smuggle in an arbitrary promotable user (or null out the audit provenance).
-                config.OnboardedBy = existingConfig.OnboardedBy;
-
                 // Safety: if GA gate is off, force UnrestrictedMode to false
                 if (!config.UnrestrictedModeEnabled)
                 {
@@ -193,16 +177,6 @@ namespace AutopilotMonitor.Functions.Functions.Config
                 // MaxNdjsonPayloadSizeMB is table-only — always preserve existing value
                 config.MaxNdjsonPayloadSizeMB = existingConfig.MaxNdjsonPayloadSizeMB;
 
-                // Plan/trial fields are mutable ONLY via the dedicated plan/trial endpoints
-                // (PATCH config/{tenantId}/plan, POST config/{tenantId}/trial). The generic PUT
-                // deserializes the full model, so without this preserve a round-tripped stale
-                // view would silently reset the tenant's edition/trial — for ALL callers, GA included.
-                config.PlanTier = existingConfig.PlanTier;
-                config.TrialExpiresUtc = existingConfig.TrialExpiresUtc;
-                config.TrialStartedUtc = existingConfig.TrialStartedUtc;
-                config.TrialConsumed = existingConfig.TrialConsumed;
-                config.TrialGrantedBy = existingConfig.TrialGrantedBy;
-
                 // Save configuration (retention cap already enforced by ValidateModel above)
                 var writeSource = ResolveWriteSource(req.Query["intent"]);
                 await _configService.SaveConfigurationAsync(config, writeSource, null);

src/Backend/AutopilotMonitor.Functions/Functions/Infrastructure/AuthFunction.cs

@@ -34,6 +34,7 @@ public class AuthFunction
     private readonly Services.Activation.ITenantAutoApproveEnqueuer _tenantAutoApproveEnqueuer;
     private readonly EntraAppRegistry _appRegistry;
     private readonly AdminIdentityResolver _identityResolver;
+    private readonly ISignalRNotificationService _signalRService;
 
     public AuthFunction(
         ILogger<AuthFunction> logger,
@@ -48,10 +49,12 @@ public class AuthFunction
         McpUserService mcpUserService,
         Services.Activation.ITenantAutoApproveEnqueuer tenantAutoApproveEnqueuer,
         EntraAppRegistry appRegistry,
-        AdminIdentityResolver identityResolver)
+        AdminIdentityResolver identityResolver,
+        ISignalRNotificationService signalRService)
     {
         _logger = logger;
         _identityResolver = identityResolver;
+        _signalRService = signalRService;
         _globalAdminService = globalAdminService;
         _delegatedAdminService = delegatedAdminService;
         _tenantConfigService = tenantConfigService;
@@ -316,6 +319,12 @@ public class AuthFunction
 
         await _globalAdminService.RemoveGlobalAdminAsync(upn);
 
+        // SignalR group authorization is join-time only: a removed Global Admin/Reader with a live
+        // connection in 'global-admins' would keep receiving cross-tenant pushes until the socket
+        // drops. Cut the UPN's connections (negotiate binds userId = lowercased UPN); a reconnect
+        // re-runs the join gates against the now-missing platform role.
+        await _signalRService.DisconnectUserAsync(upn.ToLowerInvariant());
+
         _logger.LogInformation($"Global Admin removed: {upn} by {currentUpn}");
 
         var response = req.CreateResponse(HttpStatusCode.OK);

src/Backend/AutopilotMonitor.Functions/Services/TenantConfigPatchService.cs

@@ -127,6 +127,25 @@ namespace AutopilotMonitor.Functions.Services
             "ProDowngradedUtc",
         };
 
+        /// <summary>
+        /// Full-model PUT counterpart of <see cref="BaseDeniedFields"/>: copies every denied model
+        /// property from the stored config onto the incoming one so a client body can never write
+        /// them — for ANY caller, GA included. The PUT deserializes the whole model, so a hand-kept
+        /// preserve list drifts (ProDowngradedUtc/OnboardedAt were missing, letting a tenant admin
+        /// refresh the retention-downgrade grace anchor forever). Deriving it from the single
+        /// deny-list keeps both write paths in lock-step. Server-stamped fields (TenantId,
+        /// UpdatedBy, LastUpdated) are copied too; the PUT overwrites them afterwards.
+        /// </summary>
+        internal static void PreserveDeniedFields(TenantConfiguration target, TenantConfiguration stored)
+        {
+            foreach (var name in BaseDeniedFields)
+            {
+                // PartitionKey/RowKey/Timestamp/ETag are table plumbing, not model properties.
+                if (ModelProperties.TryGetValue(name, out var prop))
+                    prop.SetValue(target, prop.GetValue(stored));
+            }
+        }
+
         /// <summary>
         /// Additional deny-list for non-GA tiers (phase 2): the GA-only toggles the PUT
         /// endpoint silently reverts for tenant admins are an explicit 400 here.