src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/OpcUaApplicationHost.cs

@@ -118,7 +118,8 @@ public sealed class OpcUaApplicationHost : IAsyncDisposable
         _server = new OtOpcUaServer(_driverHost, _authenticator, _pipelineBuilder, _loggerFactory,
             authzGate: _authzGate, scopeResolver: _scopeResolver,
             tierLookup: _tierLookup, resilienceConfigLookup: _resilienceConfigLookup,
-            virtualReadable: _virtualReadable, scriptedAlarmReadable: _scriptedAlarmReadable);
+            virtualReadable: _virtualReadable, scriptedAlarmReadable: _scriptedAlarmReadable,
+            anonymousRoles: _options.AnonymousRoles);
         await _application.Start(_server).ConfigureAwait(false);
 
         _logger.LogInformation("OPC UA server started — endpoint={Endpoint} driverCount={Count}",

src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/OpcUaServerOptions.cs

@@ -85,4 +85,15 @@ public sealed class OpcUaServerOptions
     ///     <c>LdapOptions.Enabled = false</c>, UserName token attempts are rejected.
     /// </summary>
     public LdapOptions Ldap { get; init; } = new();
+
+    /// <summary>
+    ///     Roles granted to anonymous OPC UA sessions. Default empty — anonymous clients can
+    ///     read <c>FreeAccess</c> attributes but cannot write <c>Operate</c>/<c>Tune</c>/
+    ///     <c>Configure</c> tags (<see cref="WriteAuthzPolicy"/> rejects the empty role set).
+    ///     Dev + smoke-test deployments that need anonymous writes populate this with the
+    ///     role names they want, e.g. <c>["WriteOperate"]</c> to match v1's anonymous-can-
+    ///     operate default. Production deployments leave it empty + route operators through
+    ///     UserName auth.
+    /// </summary>
+    public IReadOnlyList<string> AnonymousRoles { get; init; } = [];
 }

src/ZB.MOM.WW.OtOpcUa.Server/OpcUa/OtOpcUaServer.cs

@@ -34,6 +34,15 @@ public sealed class OtOpcUaServer : StandardServer
     private readonly IReadable? _virtualReadable;
     private readonly IReadable? _scriptedAlarmReadable;
 
+    /// <summary>
+    ///     Roles granted to anonymous sessions. When non-empty, <see cref="OnImpersonateUser"/>
+    ///     wraps <c>AnonymousIdentityToken</c> in a <see cref="RoleBasedIdentity"/> carrying
+    ///     these roles so <see cref="DriverNodeManager"/>'s write-authz check passes for
+    ///     matching classifications. Empty (the default) preserves the pre-existing behaviour
+    ///     of rejecting anonymous writes at <c>Operate</c> or higher.
+    /// </summary>
+    private readonly IReadOnlyList<string> _anonymousRoles;
+
     private readonly ILoggerFactory _loggerFactory;
     private readonly List<DriverNodeManager> _driverNodeManagers = new();
 
@@ -47,7 +56,8 @@ public sealed class OtOpcUaServer : StandardServer
         Func<string, DriverTier>? tierLookup = null,
         Func<string, string?>? resilienceConfigLookup = null,
         IReadable? virtualReadable = null,
-        IReadable? scriptedAlarmReadable = null)
+        IReadable? scriptedAlarmReadable = null,
+        IReadOnlyList<string>? anonymousRoles = null)
     {
         _driverHost = driverHost;
         _authenticator = authenticator;
@@ -58,6 +68,7 @@ public sealed class OtOpcUaServer : StandardServer
         _resilienceConfigLookup = resilienceConfigLookup;
         _virtualReadable = virtualReadable;
         _scriptedAlarmReadable = scriptedAlarmReadable;
+        _anonymousRoles = anonymousRoles ?? [];
         _loggerFactory = loggerFactory;
     }
 
@@ -112,7 +123,9 @@ public sealed class OtOpcUaServer : StandardServer
         switch (args.NewIdentity)
         {
             case AnonymousIdentityToken:
-                args.Identity = new UserIdentity(); // anonymous
+                args.Identity = _anonymousRoles.Count == 0
+                    ? new UserIdentity() // anonymous, no roles — production default
+                    : new RoleBasedIdentity("(anonymous)", "Anonymous", _anonymousRoles);
                 return;
 
             case UserNameIdentityToken user:

src/ZB.MOM.WW.OtOpcUa.Server/Program.cs

@@ -83,6 +83,7 @@ var opcUaOptions = new OpcUaServerOptions
     SecurityProfile = Enum.TryParse<OpcUaSecurityProfile>(opcUaSection.GetValue<string>("SecurityProfile"), true, out var p)
         ? p : OpcUaSecurityProfile.None,
     Ldap = ldapOptions,
+    AnonymousRoles = opcUaSection.GetSection("AnonymousRoles").Get<string[]>() ?? [],
 };
 
 builder.Services.AddSingleton(options);