diff --git a/docs/requirements/Component-ManagementService.md b/docs/requirements/Component-ManagementService.md
index 1f010103..92637b25 100644
--- a/docs/requirements/Component-ManagementService.md
+++ b/docs/requirements/Component-ManagementService.md
@@ -207,9 +207,9 @@ The two-person authorization workflow for writes through the MxAccess Gateway. B
 - **QuerySiteEventLog**: Query site event log entries from a remote site (routed via communication layer). Supports date range, keyword search, and pagination.
 - **QueryParkedMessages**: Query parked (dead-letter) messages at a remote site (routed via communication layer). Supports pagination.
 - **DebugSnapshot**: Request a one-shot snapshot of attribute values and alarm states for a running instance. Resolves the instance's site from the config DB and routes via the communication layer. Uses 30s `QueryTimeout`.
-- **BrowseNodeCommand**: Browse an OPC UA / MxGateway connection's address space one level at a time; supports a `BrowseNext` continuation token (paging) and returns per-node type-info for OPC UA Variables. (`Design` role.)
-- **SearchAddressSpaceCommand**: Bounded recursive address-space search (depth + result caps, case-insensitive substring) against an OPC UA connection. (`Design` role.)
-- **VerifyEndpointCommand**: Ask a site to probe an OPC UA endpoint (temporary client, short timeout) and report success / typed failure / a captured-but-untrusted server cert. Read-only — never trusts. (`Design` role — runs inside the Admin-gated connection editor.)
+- **BrowseNodeCommand**: Browse an OPC UA / MxGateway connection's address space one level at a time; supports a `BrowseNext` continuation token (paging) and returns per-node type-info for OPC UA Variables. Actor-dispatched — the handler requires the command's `SiteIdentifier`, enforces site-scope, then relays via `CommunicationService.BrowseNodeAsync` (arch-review C4, CLI/UI parity). (`Design` role.)
+- **SearchAddressSpaceCommand**: Bounded recursive address-space search (depth + result caps, case-insensitive substring) against an OPC UA connection. Actor-dispatched, same `SiteIdentifier`-required + site-scope pattern, relayed via `CommunicationService.SearchAddressSpaceAsync` (arch-review C4). (`Design` role.)
+- **VerifyEndpointCommand**: Ask a site to probe an OPC UA endpoint (temporary client, short timeout) and report success / typed failure / a captured-but-untrusted server cert. Read-only — never trusts. Actor-dispatched, `SiteIdentifier`-required + site-scope, relayed via `CommunicationService.VerifyEndpointAsync` (arch-review C4). (`Design` role — runs inside the Admin-gated connection editor.)
 - **TrustServerCertCommand** / **RemoveServerCertCommand** / **ListServerCertsCommand**: Manage the site's OPC UA trusted-peer PKI store; Trust/Remove broadcast to **both** site nodes (see Component-SiteRuntime.md). (`Admin` role.)
 
 ## Authorization
diff --git a/src/ZB.MOM.WW.ScadaBridge.Communication/CommunicationService.cs b/src/ZB.MOM.WW.ScadaBridge.Communication/CommunicationService.cs
index abf693c3..115754f3 100644
--- a/src/ZB.MOM.WW.ScadaBridge.Communication/CommunicationService.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.Communication/CommunicationService.cs
@@ -363,7 +363,7 @@ public class CommunicationService
     /// <param name="command">The OPC UA browse command.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
     /// <returns>The browse result (children + truncation flag + structured failure).</returns>
-    public Task<BrowseNodeResult> BrowseNodeAsync(
+    public virtual Task<BrowseNodeResult> BrowseNodeAsync(
         string siteId,
         BrowseNodeCommand command,
         CancellationToken cancellationToken = default)
@@ -385,7 +385,7 @@ public class CommunicationService
     /// <param name="command">The verify-endpoint command (connection name + protocol + serialized config).</param>
     /// <param name="cancellationToken">Cancellation token.</param>
     /// <returns>The verification result (success or classified failure, with a captured certificate when the failure is an untrusted certificate).</returns>
-    public Task<VerifyEndpointResult> VerifyEndpointAsync(
+    public virtual Task<VerifyEndpointResult> VerifyEndpointAsync(
         string siteId,
         VerifyEndpointCommand command,
         CancellationToken cancellationToken = default)
@@ -407,7 +407,7 @@ public class CommunicationService
     /// <param name="command">The address-space search command (connection name + query + depth/result caps).</param>
     /// <param name="cancellationToken">Cancellation token.</param>
     /// <returns>The search result (matches + cap-reached flag + structured failure).</returns>
-    public Task<SearchAddressSpaceResult> SearchAddressSpaceAsync(
+    public virtual Task<SearchAddressSpaceResult> SearchAddressSpaceAsync(
         string siteId,
         SearchAddressSpaceCommand command,
         CancellationToken cancellationToken = default)
diff --git a/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs b/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
index 732598c4..79556338 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ManagementService/ManagementActor.cs
@@ -243,6 +243,11 @@ public class ManagementActor : ReceiveActor
             or CreateTemplateFolderCommand or RenameTemplateFolderCommand
             or MoveTemplateFolderCommand or ReorderTemplateFolderCommand or DeleteTemplateFolderCommand
             or MoveTemplateToFolderCommand
+            // OPC UA / MxGateway design-time remote queries (arch-review C4):
+            // browse the address space, run a bounded search, and probe/verify an
+            // endpoint. Read-only against the live site server; gated Design to
+            // match the connection editor these back.
+            or BrowseNodeCommand or SearchAddressSpaceCommand or VerifyEndpointCommand
             or ExportBundleCommand => DesignerOnly,
 
         // Transport import operations (mirror the Central UI gating:
@@ -435,6 +440,9 @@ public class ManagementActor : ReceiveActor
 
             // Remote Queries
             QueryEventLogsCommand cmd => await HandleQueryEventLogs(sp, cmd, user),
+            BrowseNodeCommand cmd => await HandleBrowseNode(sp, cmd, user),
+            SearchAddressSpaceCommand cmd => await HandleSearchAddressSpace(sp, cmd, user),
+            VerifyEndpointCommand cmd => await HandleVerifyEndpoint(sp, cmd, user),
             QueryParkedMessagesCommand cmd => await HandleQueryParkedMessages(sp, cmd, user),
             RetryParkedMessageCommand cmd => await HandleRetryParkedMessage(sp, cmd, user),
             DiscardParkedMessageCommand cmd => await HandleDiscardParkedMessage(sp, cmd, user),
@@ -2914,6 +2922,39 @@ public class ManagementActor : ReceiveActor
         return await commService.QueryEventLogsAsync(cmd.SiteIdentifier, request);
     }
 
+    // OPC UA / MxGateway design-time remote queries (arch-review C4). These
+    // handlers give the management API/CLI parity with the Central UI, which
+    // already reaches these site actors directly. SiteIdentifier is REQUIRED —
+    // the actor must know which site to route to — and site-scope is enforced
+    // before relaying, exactly like HandleQueryEventLogs.
+
+    private static async Task<object?> HandleBrowseNode(IServiceProvider sp, BrowseNodeCommand cmd, AuthenticatedUser user)
+    {
+        var site = cmd.SiteIdentifier
+            ?? throw new ManagementCommandException("SiteIdentifier is required when browsing an address space via the management API.");
+        await EnforceSiteScopeForIdentifier(sp, user, site);
+        var commService = sp.GetRequiredService<CommunicationService>();
+        return await commService.BrowseNodeAsync(site, cmd);
+    }
+
+    private static async Task<object?> HandleSearchAddressSpace(IServiceProvider sp, SearchAddressSpaceCommand cmd, AuthenticatedUser user)
+    {
+        var site = cmd.SiteIdentifier
+            ?? throw new ManagementCommandException("SiteIdentifier is required when searching an address space via the management API.");
+        await EnforceSiteScopeForIdentifier(sp, user, site);
+        var commService = sp.GetRequiredService<CommunicationService>();
+        return await commService.SearchAddressSpaceAsync(site, cmd);
+    }
+
+    private static async Task<object?> HandleVerifyEndpoint(IServiceProvider sp, VerifyEndpointCommand cmd, AuthenticatedUser user)
+    {
+        var site = cmd.SiteIdentifier
+            ?? throw new ManagementCommandException("SiteIdentifier is required when verifying an endpoint via the management API.");
+        await EnforceSiteScopeForIdentifier(sp, user, site);
+        var commService = sp.GetRequiredService<CommunicationService>();
+        return await commService.VerifyEndpointAsync(site, cmd);
+    }
+
     private static async Task<object?> HandleQueryParkedMessages(IServiceProvider sp, QueryParkedMessagesCommand cmd, AuthenticatedUser user)
     {
         await EnforceSiteScopeForIdentifier(sp, user, cmd.SiteIdentifier);
diff --git a/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs
index 46be4b0a..888c80bc 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/ManagementActorTests.cs
@@ -2,13 +2,16 @@ using Akka.Actor;
 using Akka.TestKit.Xunit2;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
 using NSubstitute;
+using ZB.MOM.WW.ScadaBridge.Communication;
 using NSubstitute.ExceptionExtensions;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.Instances;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.Schemas;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.SecuredWrites;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.Scripts;
 using ZB.MOM.WW.ScadaBridge.Commons.Entities.Templates;
+using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Protocol;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories;
 using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Services;
 using ZB.MOM.WW.ScadaBridge.Commons.Messages.Management;
@@ -3152,4 +3155,142 @@ public class ManagementActorTests : TestKit, IDisposable
         actor.Tell(Envelope(new CreateAreaCommand(1, "Area1", null), "Viewer"));
         ExpectMsg<ManagementUnauthorized>(TimeSpan.FromSeconds(5));
     }
+
+    // ========================================================================
+    // Remote-query actor dispatch for the OPC UA design-time commands
+    // (arch-review C4): BrowseNode / SearchAddressSpace / VerifyEndpoint gain
+    // actor handlers so the management API/CLI reaches parity with the UI.
+    // SiteIdentifier is REQUIRED (the actor must route to a site); Designer-gated.
+    // ========================================================================
+
+    [Fact]
+    public void BrowseNode_WithoutSiteIdentifier_ReturnsError()
+    {
+        var actor = CreateActor();
+        actor.Tell(Envelope(new BrowseNodeCommand("conn", null, null), "Designer"));
+        var resp = ExpectMsg<ManagementError>(TimeSpan.FromSeconds(5));
+        Assert.Contains("SiteIdentifier", resp.Error);
+    }
+
+    [Fact]
+    public void BrowseNode_Designer_RelaysToSite()
+    {
+        var stub = new StubCommunicationService();
+        _services.AddSingleton<CommunicationService>(stub);
+        var actor = CreateActor();
+        actor.Tell(Envelope(new BrowseNodeCommand("conn", null, null, "SITE1"), "Designer"));
+        ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+        Assert.Equal(1, stub.BrowseCount);
+        Assert.Equal("SITE1", stub.LastBrowseSite);
+    }
+
+    [Fact]
+    public void BrowseNode_ViewerOnly_Unauthorized()
+    {
+        var actor = CreateActor();
+        actor.Tell(Envelope(new BrowseNodeCommand("conn", null, null, "SITE1"), "Viewer"));
+        ExpectMsg<ManagementUnauthorized>(TimeSpan.FromSeconds(5));
+    }
+
+    [Fact]
+    public void SearchAddressSpace_WithoutSiteIdentifier_ReturnsError()
+    {
+        var actor = CreateActor();
+        actor.Tell(Envelope(new SearchAddressSpaceCommand("conn", "q", 3, 50), "Designer"));
+        var resp = ExpectMsg<ManagementError>(TimeSpan.FromSeconds(5));
+        Assert.Contains("SiteIdentifier", resp.Error);
+    }
+
+    [Fact]
+    public void SearchAddressSpace_Designer_RelaysToSite()
+    {
+        var stub = new StubCommunicationService();
+        _services.AddSingleton<CommunicationService>(stub);
+        var actor = CreateActor();
+        actor.Tell(Envelope(new SearchAddressSpaceCommand("conn", "q", 3, 50, "SITE1"), "Designer"));
+        ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+        Assert.Equal(1, stub.SearchCount);
+        Assert.Equal("SITE1", stub.LastSearchSite);
+    }
+
+    [Fact]
+    public void SearchAddressSpace_ViewerOnly_Unauthorized()
+    {
+        var actor = CreateActor();
+        actor.Tell(Envelope(new SearchAddressSpaceCommand("conn", "q", 3, 50, "SITE1"), "Viewer"));
+        ExpectMsg<ManagementUnauthorized>(TimeSpan.FromSeconds(5));
+    }
+
+    [Fact]
+    public void VerifyEndpoint_WithoutSiteIdentifier_ReturnsError()
+    {
+        var actor = CreateActor();
+        actor.Tell(Envelope(new VerifyEndpointCommand("conn", "OpcUa", "{}"), "Designer"));
+        var resp = ExpectMsg<ManagementError>(TimeSpan.FromSeconds(5));
+        Assert.Contains("SiteIdentifier", resp.Error);
+    }
+
+    [Fact]
+    public void VerifyEndpoint_Designer_RelaysToSite()
+    {
+        var stub = new StubCommunicationService();
+        _services.AddSingleton<CommunicationService>(stub);
+        var actor = CreateActor();
+        actor.Tell(Envelope(new VerifyEndpointCommand("conn", "OpcUa", "{}", "SITE1"), "Designer"));
+        ExpectMsg<ManagementSuccess>(TimeSpan.FromSeconds(5));
+        Assert.Equal(1, stub.VerifyCount);
+        Assert.Equal("SITE1", stub.LastVerifySite);
+    }
+
+    [Fact]
+    public void VerifyEndpoint_ViewerOnly_Unauthorized()
+    {
+        var actor = CreateActor();
+        actor.Tell(Envelope(new VerifyEndpointCommand("conn", "OpcUa", "{}", "SITE1"), "Viewer"));
+        ExpectMsg<ManagementUnauthorized>(TimeSpan.FromSeconds(5));
+    }
+
+    /// <summary>
+    /// Records remote-query relays for the actor-dispatch tests. The browse /
+    /// search / verify / cert-trust methods on <see cref="CommunicationService"/>
+    /// are virtual so the relay can be exercised without a live actor system.
+    /// </summary>
+    private sealed class StubCommunicationService : CommunicationService
+    {
+        public StubCommunicationService()
+            : base(Options.Create(new CommunicationOptions()), NullLogger<CommunicationService>.Instance)
+        {
+        }
+
+        public int BrowseCount { get; private set; }
+        public string? LastBrowseSite { get; private set; }
+        public int SearchCount { get; private set; }
+        public string? LastSearchSite { get; private set; }
+        public int VerifyCount { get; private set; }
+        public string? LastVerifySite { get; private set; }
+
+        public override Task<BrowseNodeResult> BrowseNodeAsync(
+            string siteId, BrowseNodeCommand command, CancellationToken ct = default)
+        {
+            BrowseCount++;
+            LastBrowseSite = siteId;
+            return Task.FromResult(new BrowseNodeResult(Array.Empty<BrowseNode>(), false, null));
+        }
+
+        public override Task<SearchAddressSpaceResult> SearchAddressSpaceAsync(
+            string siteId, SearchAddressSpaceCommand command, CancellationToken ct = default)
+        {
+            SearchCount++;
+            LastSearchSite = siteId;
+            return Task.FromResult(new SearchAddressSpaceResult(Array.Empty<AddressSpaceMatch>(), false, null));
+        }
+
+        public override Task<VerifyEndpointResult> VerifyEndpointAsync(
+            string siteId, VerifyEndpointCommand command, CancellationToken ct = default)
+        {
+            VerifyCount++;
+            LastVerifySite = siteId;
+            return Task.FromResult(new VerifyEndpointResult(true, null, null, null));
+        }
+    }
 }