diff --git a/src/Device.tt b/src/Device.tt
index 500fe69..ae2abd9 100644
--- a/src/Device.tt
+++ b/src/Device.tt
@@ -12,6 +12,11 @@
 var publicRegisters = DeviceMetadata.Registers.Where(register => register.Value.Visibility == RegisterVisibility.Public).ToList();
 var deviceRegisters = DeviceMetadata.Registers;
 var deviceName = DeviceMetadata.Device;
+var isApplicationDevice = DeviceMetadata.IsApplicationDevice;
+#>
+<#
+if (isApplicationDevice)
+{
 #>
 using Bonsai;
 using Bonsai.Harp;
@@ -21,9 +26,25 @@ using System.ComponentModel;
 using System.Linq;
 using System.Reactive.Linq;
 using System.Xml.Serialization;
+<#
+}
+else
+{
+#>
+using Bonsai.Harp;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+<#
+} // isApplicationDevice
+#>
 
 namespace <#= Namespace #>
 {
+<#
+if (isApplicationDevice)
+{
+#>
     /// <summary>
     /// Generates events and processes commands for the <#= deviceName #> device connected
     /// at the specified serial port.
@@ -53,6 +74,19 @@ namespace <#= Namespace #>
             (Bonsai.Harp.Device.RegisterMap.ToDictionary(entry => entry.Key, entry => entry.Value))
         {
 <#
+}
+else
+{
+#>
+    public partial class Device
+    {
+        /// <summary>
+        /// Gets a read-only mapping from address to register type.
+        /// </summary>
+        public static IReadOnlyDictionary<int, Type> RegisterMap { get; } = new Dictionary<int, Type>
+        {
+<#
+} // isApplicationDevice
 int registerIndex = 0;
 foreach (var register in deviceRegisters)
 {
@@ -62,6 +96,10 @@ foreach (var register in deviceRegisters)
 }
 #>
         };
+<#
+if (isApplicationDevice)
+{
+#>
 
         /// <summary>
         /// Gets the contents of the metadata file describing the <see cref="<#= deviceName #>"/>
@@ -76,7 +114,14 @@ foreach (var register in deviceRegisters)
             using var streamReader = new System.IO.StreamReader(metadataStream);
             return streamReader.ReadToEnd();
         }
+<#
+} // isApplicationDevice
+#>
     }
+<#
+if (isApplicationDevice)
+{
+#>
 
     /// <summary>
     /// Represents an operator that returns the contents of the metadata file
@@ -388,6 +433,8 @@ foreach (var register in publicRegisters)
         string INamedElement.Name => $"{nameof(<#= deviceName #>)}.{GetElementDisplayName(Register)}";
     }
 <#
+} // deviceRegisters.Count > 0
+} // isApplicationDevice
 foreach (var registerMetadata in deviceRegisters)
 {
     var register = registerMetadata.Value;
@@ -647,6 +694,8 @@ if (isPrivate)
     }
 <#
 }
+if (isApplicationDevice && deviceRegisters.Count > 0)
+{
 #>
 
     /// <summary>
@@ -691,6 +740,7 @@ foreach (var register in publicRegisters)
         string INamedElement.Name => $"{nameof(<#= deviceName #>)}.{GetElementDisplayName(Payload)}";
     }
 <#
+} // isApplicationDevice && deviceRegisters.Count > 0
 foreach (var registerMetadata in publicRegisters)
 {
     var register = registerMetadata.Value;
@@ -824,9 +874,6 @@ foreach (var registerMetadata in publicRegisters)
 }
 #>
 <#
-} // deviceRegisters.Count > 0
-#>
-<#
 var payloadTypes = new HashSet<string>();
 foreach (var registerMetadata in deviceRegisters)
 {
diff --git a/src/Interface.cs b/src/Interface.cs
index dbbe25d..e2a75b6 100644
--- a/src/Interface.cs
+++ b/src/Interface.cs
@@ -54,6 +54,12 @@ public class DeviceMetadata
     /// Specifies the collection of group masks available to be used with the different registers.
     /// </summary>
     public Dictionary<string, GroupMaskInfo> GroupMasks = [];
+
+    /// <summary>
+    /// Gets a value indicating whether the metadata describes an application device.
+    /// </summary>
+    [YamlIgnore]
+    public bool IsApplicationDevice => !string.IsNullOrEmpty(Device);
 }
 
 /// <summary>
diff --git a/src/InterfaceGenerator.cs b/src/InterfaceGenerator.cs
index 0d4ead4..ffe21b3 100644
--- a/src/InterfaceGenerator.cs
+++ b/src/InterfaceGenerator.cs
@@ -12,6 +12,7 @@ public sealed class InterfaceGenerator
     readonly Device _deviceTemplate = new();
     readonly AsyncDevice _asyncDeviceTemplate = new();
     readonly CompilerErrorCollection errors = [];
+    readonly bool isApplicationDevice;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="InterfaceGenerator"/> class with the
@@ -28,6 +29,7 @@ public InterfaceGenerator(DeviceMetadata deviceMetadata, string ns)
         };
         _deviceTemplate.Initialize(InterfaceImplementation.DeviceFileName, errors, session);
         _asyncDeviceTemplate.Initialize(InterfaceImplementation.AsyncDeviceFileName, errors, session);
+        isApplicationDevice = deviceMetadata.IsApplicationDevice;
     }
 
     /// <summary>
@@ -41,7 +43,7 @@ public InterfaceGenerator(DeviceMetadata deviceMetadata, string ns)
     /// <returns>The generated device interface implementation.</returns>
     public InterfaceImplementation GenerateImplementation() =>
         new(Device: _deviceTemplate.TransformText(),
-            AsyncDevice: _asyncDeviceTemplate.TransformText());
+            AsyncDevice: isApplicationDevice ? _asyncDeviceTemplate.TransformText() : string.Empty);
 }
 
 /// <summary>
@@ -72,7 +74,8 @@ public record struct InterfaceImplementation(string Device, string AsyncDevice)
     public readonly IEnumerator<KeyValuePair<string, string>> GetEnumerator()
     {
         yield return new(DeviceFileName, Device);
-        yield return new(AsyncDeviceFileName, AsyncDevice);
+        if (!string.IsNullOrEmpty(AsyncDevice))
+            yield return new(AsyncDeviceFileName, AsyncDevice);
     }
 
     readonly IEnumerator IEnumerable.GetEnumerator()
diff --git a/src/Python.cs b/src/Python.cs
index 5f9f146..9ba43f8 100644
--- a/src/Python.cs
+++ b/src/Python.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
-using System.Linq;
 using Bonsai.Harp;
 
 namespace Harp.Generators;
@@ -77,7 +76,6 @@ internal sealed class PythonRegister
 
 internal static partial class TemplateHelper
 {
-    const int CoreRegisterAddressLimit = 32;
     const string CoreMetadataResourceName = "Harp.Generators.core.yml";
 
     static readonly Dictionary<string, string> PrimitiveNumpyTypes = new()
@@ -215,7 +213,7 @@ public static PythonModule BuildPythonModule(DeviceMetadata deviceMetadata)
             BuildPythonRegister(module, registerMetadata.Key, registerMetadata.Value, deviceMetadata);
 
         module.ProtocolImports.Add("RegisterBase");
-        module.IsApplicationDevice = deviceMetadata.Registers.Values.All(register => register.Address >= CoreRegisterAddressLimit);
+        module.IsApplicationDevice = deviceMetadata.IsApplicationDevice;
         return module;
     }
 
diff --git a/src/core.yml b/src/core.yml
index 2610747..507c516 100644
--- a/src/core.yml
+++ b/src/core.yml
@@ -1,6 +1,5 @@
 # yaml-language-server: $schema=https://harp-tech.org/draft-02/schema/registers.json
 description: The core register set every Harp device carries, and its address space.
-device: Tests
 registers:
   WhoAmI:
     address: 0
diff --git a/tests/ExpectedOutput/core.cs b/tests/ExpectedOutput/core.cs
index 720b8d1..bd7b8c5 100644
--- a/tests/ExpectedOutput/core.cs
+++ b/tests/ExpectedOutput/core.cs
@@ -1,41 +1,16 @@
-using Bonsai;
 using Bonsai.Harp;
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
-using System.Linq;
-using System.Reactive.Linq;
-using System.Xml.Serialization;
 
 namespace Harp.Generators.Tests
 {
-    /// <summary>
-    /// Generates events and processes commands for the Tests device connected
-    /// at the specified serial port.
-    /// </summary>
-    [Combinator(MethodName = nameof(Generate))]
-    [WorkflowElementCategory(ElementCategory.Source)]
-    [Description("Generates events and processes commands for the Tests device.")]
-    public partial class Device : Bonsai.Harp.Device, INamedElement
+    public partial class Device
     {
-        /// <summary>
-        /// Represents the unique identity class of the <see cref="Tests"/> device.
-        /// This field is constant.
-        /// </summary>
-        public const int WhoAmI = 0;
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Device"/> class.
-        /// </summary>
-        public Device() : base(WhoAmI) { }
-
-        string INamedElement.Name => nameof(Tests);
-
         /// <summary>
         /// Gets a read-only mapping from address to register type.
         /// </summary>
-        public static new IReadOnlyDictionary<int, Type> RegisterMap { get; } = new Dictionary<int, Type>
-            (Bonsai.Harp.Device.RegisterMap.ToDictionary(entry => entry.Key, entry => entry.Value))
+        public static IReadOnlyDictionary<int, Type> RegisterMap { get; } = new Dictionary<int, Type>
         {
             { 0, typeof(WhoAmI) },
             { 1, typeof(HardwareVersionHigh) },
@@ -53,375 +28,6 @@ public Device() : base(WhoAmI) { }
             { 13, typeof(SerialNumber) },
             { 14, typeof(ClockConfiguration) }
         };
-
-        /// <summary>
-        /// Gets the contents of the metadata file describing the <see cref="Tests"/>
-        /// device registers.
-        /// </summary>
-        public static readonly string Metadata = GetDeviceMetadata();
-
-        static string GetDeviceMetadata()
-        {
-            var deviceType = typeof(Device);
-            using var metadataStream = deviceType.Assembly.GetManifestResourceStream($"{deviceType.Namespace}.device.yml");
-            using var streamReader = new System.IO.StreamReader(metadataStream);
-            return streamReader.ReadToEnd();
-        }
-    }
-
-    /// <summary>
-    /// Represents an operator that returns the contents of the metadata file
-    /// describing the <see cref="Tests"/> device registers.
-    /// </summary>
-    [Description("Returns the contents of the metadata file describing the Tests device registers.")]
-    public partial class GetDeviceMetadata : Source<string>
-    {
-        /// <summary>
-        /// Returns an observable sequence with the contents of the metadata file
-        /// describing the <see cref="Tests"/> device registers.
-        /// </summary>
-        /// <returns>
-        /// A sequence with a single <see cref="string"/> object representing the
-        /// contents of the metadata file.
-        /// </returns>
-        public override IObservable<string> Generate()
-        {
-            return Observable.Return(Device.Metadata);
-        }
-    }
-
-    /// <summary>
-    /// Represents an operator that groups the sequence of <see cref="Tests"/>" messages by register type.
-    /// </summary>
-    [Description("Groups the sequence of Tests messages by register type.")]
-    public partial class GroupByRegister : Combinator<HarpMessage, IGroupedObservable<Type, HarpMessage>>
-    {
-        /// <summary>
-        /// Groups an observable sequence of <see cref="Tests"/> messages
-        /// by register type.
-        /// </summary>
-        /// <param name="source">The sequence of Harp device messages.</param>
-        /// <returns>
-        /// A sequence of observable groups, each of which corresponds to a unique
-        /// <see cref="Tests"/> register.
-        /// </returns>
-        public override IObservable<IGroupedObservable<Type, HarpMessage>> Process(IObservable<HarpMessage> source)
-        {
-            return source.GroupBy(message => Device.RegisterMap[message.Address]);
-        }
-    }
-
-    /// <summary>
-    /// Represents an operator that writes the sequence of <see cref="Tests"/>" messages
-    /// to the standard Harp storage format.
-    /// </summary>
-    [DefaultProperty(nameof(Path))]
-    [Description("Writes the sequence of Tests messages to the standard Harp storage format.")]
-    public partial class DeviceDataWriter : Sink<HarpMessage>, INamedElement
-    {
-        const string BinaryExtension = ".bin";
-        const string MetadataFileName = "device.yml";
-        readonly Bonsai.Harp.MessageWriter writer = new();
-
-        string INamedElement.Name => nameof(Tests) + "DataWriter";
-
-        /// <summary>
-        /// Gets or sets the relative or absolute path on which to save the message data.
-        /// </summary>
-        [Description("The relative or absolute path of the directory on which to save the message data.")]
-        [Editor("Bonsai.Design.SaveFileNameEditor, Bonsai.Design", DesignTypes.UITypeEditor)]
-        public string Path
-        {
-            get => System.IO.Path.GetDirectoryName(writer.FileName);
-            set => writer.FileName = System.IO.Path.Combine(value, nameof(Tests) + BinaryExtension);
-        }
-
-        /// <summary>
-        /// Gets or sets a value indicating whether element writing should be buffered. If <see langword="true"/>,
-        /// the write commands will be queued in memory as fast as possible and will be processed
-        /// by the writer in a different thread. Otherwise, writing will be done in the same
-        /// thread in which notifications arrive.
-        /// </summary>
-        [Description("Indicates whether writing should be buffered.")]
-        public bool Buffered
-        {
-            get => writer.Buffered;
-            set => writer.Buffered = value;
-        }
-
-        /// <summary>
-        /// Gets or sets a value indicating whether to overwrite the output file if it already exists.
-        /// </summary>
-        [Description("Indicates whether to overwrite the output file if it already exists.")]
-        public bool Overwrite
-        {
-            get => writer.Overwrite;
-            set => writer.Overwrite = value;
-        }
-
-        /// <summary>
-        /// Gets or sets a value specifying how the message filter will use the matching criteria.
-        /// </summary>
-        [Description("Specifies how the message filter will use the matching criteria.")]
-        public FilterType FilterType
-        {
-            get => writer.FilterType;
-            set => writer.FilterType = value;
-        }
-
-        /// <summary>
-        /// Gets or sets a value specifying the expected message type. If no value is
-        /// specified, all messages will be accepted.
-        /// </summary>
-        [Description("Specifies the expected message type. If no value is specified, all messages will be accepted.")]
-        public MessageType? MessageType
-        {
-            get => writer.MessageType;
-            set => writer.MessageType = value;
-        }
-
-        private IObservable<TSource> WriteDeviceMetadata<TSource>(IObservable<TSource> source)
-        {
-            var basePath = Path;
-            if (string.IsNullOrEmpty(basePath))
-                return source;
-
-            var metadataPath = System.IO.Path.Combine(basePath, MetadataFileName);
-            return Observable.Create<TSource>(observer =>
-            {
-                Bonsai.IO.PathHelper.EnsureDirectory(metadataPath);
-                if (System.IO.File.Exists(metadataPath) && !Overwrite)
-                {
-                    throw new System.IO.IOException(string.Format("The file '{0}' already exists.", metadataPath));
-                }
-
-                System.IO.File.WriteAllText(metadataPath, Device.Metadata);
-                return source.SubscribeSafe(observer);
-            });
-        }
-
-        /// <summary>
-        /// Writes each Harp message in the sequence to the specified binary file, and the
-        /// contents of the device metadata file to a separate text file.
-        /// </summary>
-        /// <param name="source">The sequence of messages to write to the file.</param>
-        /// <returns>
-        /// An observable sequence that is identical to the <paramref name="source"/>
-        /// sequence but where there is an additional side effect of writing the
-        /// messages to a raw binary file, and the contents of the device metadata file
-        /// to a separate text file.
-        /// </returns>
-        public override IObservable<HarpMessage> Process(IObservable<HarpMessage> source)
-        {
-            return source.Publish(ps => ps.Merge(
-                WriteDeviceMetadata(writer.Process(ps.GroupBy(message => message.Address)))
-                .IgnoreElements()
-                .Cast<HarpMessage>()));
-        }
-
-        /// <summary>
-        /// Writes each Harp message in the sequence of observable groups to the
-        /// corresponding binary file, where the name of each file is generated from
-        /// the common group register address. The contents of the device metadata file are
-        /// written to a separate text file.
-        /// </summary>
-        /// <param name="source">
-        /// A sequence of observable groups, each of which corresponds to a unique register
-        /// address.
-        /// </param>
-        /// <returns>
-        /// An observable sequence that is identical to the <paramref name="source"/>
-        /// sequence but where there is an additional side effect of writing the Harp
-        /// messages in each group to the corresponding file, and the contents of the device
-        /// metadata file to a separate text file.
-        /// </returns>
-        public IObservable<IGroupedObservable<int, HarpMessage>> Process(IObservable<IGroupedObservable<int, HarpMessage>> source)
-        {
-            return WriteDeviceMetadata(writer.Process(source));
-        }
-
-        /// <summary>
-        /// Writes each Harp message in the sequence of observable groups to the
-        /// corresponding binary file, where the name of each file is generated from
-        /// the common group register name. The contents of the device metadata file are
-        /// written to a separate text file.
-        /// </summary>
-        /// <param name="source">
-        /// A sequence of observable groups, each of which corresponds to a unique register
-        /// type.
-        /// </param>
-        /// <returns>
-        /// An observable sequence that is identical to the <paramref name="source"/>
-        /// sequence but where there is an additional side effect of writing the Harp
-        /// messages in each group to the corresponding file, and the contents of the device
-        /// metadata file to a separate text file.
-        /// </returns>
-        public IObservable<IGroupedObservable<Type, HarpMessage>> Process(IObservable<IGroupedObservable<Type, HarpMessage>> source)
-        {
-            return WriteDeviceMetadata(writer.Process(source));
-        }
-    }
-
-    /// <summary>
-    /// Represents an operator that filters register-specific messages
-    /// reported by the <see cref="Tests"/> device.
-    /// </summary>
-    /// <seealso cref="WhoAmI"/>
-    /// <seealso cref="HardwareVersionHigh"/>
-    /// <seealso cref="HardwareVersionLow"/>
-    /// <seealso cref="AssemblyVersion"/>
-    /// <seealso cref="CoreVersionHigh"/>
-    /// <seealso cref="CoreVersionLow"/>
-    /// <seealso cref="FirmwareVersionHigh"/>
-    /// <seealso cref="FirmwareVersionLow"/>
-    /// <seealso cref="TimestampSeconds"/>
-    /// <seealso cref="TimestampMicroseconds"/>
-    /// <seealso cref="OperationControl"/>
-    /// <seealso cref="ResetDevice"/>
-    /// <seealso cref="DeviceName"/>
-    /// <seealso cref="SerialNumber"/>
-    /// <seealso cref="ClockConfiguration"/>
-    [XmlInclude(typeof(WhoAmI))]
-    [XmlInclude(typeof(HardwareVersionHigh))]
-    [XmlInclude(typeof(HardwareVersionLow))]
-    [XmlInclude(typeof(AssemblyVersion))]
-    [XmlInclude(typeof(CoreVersionHigh))]
-    [XmlInclude(typeof(CoreVersionLow))]
-    [XmlInclude(typeof(FirmwareVersionHigh))]
-    [XmlInclude(typeof(FirmwareVersionLow))]
-    [XmlInclude(typeof(TimestampSeconds))]
-    [XmlInclude(typeof(TimestampMicroseconds))]
-    [XmlInclude(typeof(OperationControl))]
-    [XmlInclude(typeof(ResetDevice))]
-    [XmlInclude(typeof(DeviceName))]
-    [XmlInclude(typeof(SerialNumber))]
-    [XmlInclude(typeof(ClockConfiguration))]
-    [Description("Filters register-specific messages reported by the Tests device.")]
-    public class FilterRegister : FilterRegisterBuilder, INamedElement
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="FilterRegister"/> class.
-        /// </summary>
-        public FilterRegister()
-        {
-            Register = new WhoAmI();
-        }
-
-        string INamedElement.Name
-        {
-            get => $"{nameof(Tests)}.{GetElementDisplayName(Register)}";
-        }
-    }
-
-    /// <summary>
-    /// Represents an operator which filters and selects specific messages
-    /// reported by the Tests device.
-    /// </summary>
-    /// <seealso cref="WhoAmI"/>
-    /// <seealso cref="HardwareVersionHigh"/>
-    /// <seealso cref="HardwareVersionLow"/>
-    /// <seealso cref="AssemblyVersion"/>
-    /// <seealso cref="CoreVersionHigh"/>
-    /// <seealso cref="CoreVersionLow"/>
-    /// <seealso cref="FirmwareVersionHigh"/>
-    /// <seealso cref="FirmwareVersionLow"/>
-    /// <seealso cref="TimestampSeconds"/>
-    /// <seealso cref="TimestampMicroseconds"/>
-    /// <seealso cref="OperationControl"/>
-    /// <seealso cref="ResetDevice"/>
-    /// <seealso cref="DeviceName"/>
-    /// <seealso cref="SerialNumber"/>
-    /// <seealso cref="ClockConfiguration"/>
-    [XmlInclude(typeof(WhoAmI))]
-    [XmlInclude(typeof(HardwareVersionHigh))]
-    [XmlInclude(typeof(HardwareVersionLow))]
-    [XmlInclude(typeof(AssemblyVersion))]
-    [XmlInclude(typeof(CoreVersionHigh))]
-    [XmlInclude(typeof(CoreVersionLow))]
-    [XmlInclude(typeof(FirmwareVersionHigh))]
-    [XmlInclude(typeof(FirmwareVersionLow))]
-    [XmlInclude(typeof(TimestampSeconds))]
-    [XmlInclude(typeof(TimestampMicroseconds))]
-    [XmlInclude(typeof(OperationControl))]
-    [XmlInclude(typeof(ResetDevice))]
-    [XmlInclude(typeof(DeviceName))]
-    [XmlInclude(typeof(SerialNumber))]
-    [XmlInclude(typeof(ClockConfiguration))]
-    [XmlInclude(typeof(TimestampedWhoAmI))]
-    [XmlInclude(typeof(TimestampedHardwareVersionHigh))]
-    [XmlInclude(typeof(TimestampedHardwareVersionLow))]
-    [XmlInclude(typeof(TimestampedAssemblyVersion))]
-    [XmlInclude(typeof(TimestampedCoreVersionHigh))]
-    [XmlInclude(typeof(TimestampedCoreVersionLow))]
-    [XmlInclude(typeof(TimestampedFirmwareVersionHigh))]
-    [XmlInclude(typeof(TimestampedFirmwareVersionLow))]
-    [XmlInclude(typeof(TimestampedTimestampSeconds))]
-    [XmlInclude(typeof(TimestampedTimestampMicroseconds))]
-    [XmlInclude(typeof(TimestampedOperationControl))]
-    [XmlInclude(typeof(TimestampedResetDevice))]
-    [XmlInclude(typeof(TimestampedDeviceName))]
-    [XmlInclude(typeof(TimestampedSerialNumber))]
-    [XmlInclude(typeof(TimestampedClockConfiguration))]
-    [Description("Filters and selects specific messages reported by the Tests device.")]
-    public partial class Parse : ParseBuilder, INamedElement
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Parse"/> class.
-        /// </summary>
-        public Parse()
-        {
-            Register = new WhoAmI();
-        }
-
-        string INamedElement.Name => $"{nameof(Tests)}.{GetElementDisplayName(Register)}";
-    }
-
-    /// <summary>
-    /// Represents an operator which formats a sequence of values as specific
-    /// Tests register messages.
-    /// </summary>
-    /// <seealso cref="WhoAmI"/>
-    /// <seealso cref="HardwareVersionHigh"/>
-    /// <seealso cref="HardwareVersionLow"/>
-    /// <seealso cref="AssemblyVersion"/>
-    /// <seealso cref="CoreVersionHigh"/>
-    /// <seealso cref="CoreVersionLow"/>
-    /// <seealso cref="FirmwareVersionHigh"/>
-    /// <seealso cref="FirmwareVersionLow"/>
-    /// <seealso cref="TimestampSeconds"/>
-    /// <seealso cref="TimestampMicroseconds"/>
-    /// <seealso cref="OperationControl"/>
-    /// <seealso cref="ResetDevice"/>
-    /// <seealso cref="DeviceName"/>
-    /// <seealso cref="SerialNumber"/>
-    /// <seealso cref="ClockConfiguration"/>
-    [XmlInclude(typeof(WhoAmI))]
-    [XmlInclude(typeof(HardwareVersionHigh))]
-    [XmlInclude(typeof(HardwareVersionLow))]
-    [XmlInclude(typeof(AssemblyVersion))]
-    [XmlInclude(typeof(CoreVersionHigh))]
-    [XmlInclude(typeof(CoreVersionLow))]
-    [XmlInclude(typeof(FirmwareVersionHigh))]
-    [XmlInclude(typeof(FirmwareVersionLow))]
-    [XmlInclude(typeof(TimestampSeconds))]
-    [XmlInclude(typeof(TimestampMicroseconds))]
-    [XmlInclude(typeof(OperationControl))]
-    [XmlInclude(typeof(ResetDevice))]
-    [XmlInclude(typeof(DeviceName))]
-    [XmlInclude(typeof(SerialNumber))]
-    [XmlInclude(typeof(ClockConfiguration))]
-    [Description("Formats a sequence of values as specific Tests register messages.")]
-    public partial class Format : FormatBuilder, INamedElement
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="Format"/> class.
-        /// </summary>
-        public Format()
-        {
-            Register = new WhoAmI();
-        }
-
-        string INamedElement.Name => $"{nameof(Tests)}.{GetElementDisplayName(Register)}";
     }
 
     /// <summary>
@@ -1899,69 +1505,6 @@ public static Timestamped<ClockConfigurationFlags> GetPayload(HarpMessage messag
         }
     }
 
-    /// <summary>
-    /// Represents an operator which creates standard message payloads for the
-    /// Tests device.
-    /// </summary>
-    /// <seealso cref="CreateWhoAmIPayload"/>
-    /// <seealso cref="CreateHardwareVersionHighPayload"/>
-    /// <seealso cref="CreateHardwareVersionLowPayload"/>
-    /// <seealso cref="CreateAssemblyVersionPayload"/>
-    /// <seealso cref="CreateCoreVersionHighPayload"/>
-    /// <seealso cref="CreateCoreVersionLowPayload"/>
-    /// <seealso cref="CreateFirmwareVersionHighPayload"/>
-    /// <seealso cref="CreateFirmwareVersionLowPayload"/>
-    /// <seealso cref="CreateTimestampSecondsPayload"/>
-    /// <seealso cref="CreateTimestampMicrosecondsPayload"/>
-    /// <seealso cref="CreateOperationControlPayload"/>
-    /// <seealso cref="CreateResetDevicePayload"/>
-    /// <seealso cref="CreateDeviceNamePayload"/>
-    /// <seealso cref="CreateSerialNumberPayload"/>
-    /// <seealso cref="CreateClockConfigurationPayload"/>
-    [XmlInclude(typeof(CreateWhoAmIPayload))]
-    [XmlInclude(typeof(CreateHardwareVersionHighPayload))]
-    [XmlInclude(typeof(CreateHardwareVersionLowPayload))]
-    [XmlInclude(typeof(CreateAssemblyVersionPayload))]
-    [XmlInclude(typeof(CreateCoreVersionHighPayload))]
-    [XmlInclude(typeof(CreateCoreVersionLowPayload))]
-    [XmlInclude(typeof(CreateFirmwareVersionHighPayload))]
-    [XmlInclude(typeof(CreateFirmwareVersionLowPayload))]
-    [XmlInclude(typeof(CreateTimestampSecondsPayload))]
-    [XmlInclude(typeof(CreateTimestampMicrosecondsPayload))]
-    [XmlInclude(typeof(CreateOperationControlPayload))]
-    [XmlInclude(typeof(CreateResetDevicePayload))]
-    [XmlInclude(typeof(CreateDeviceNamePayload))]
-    [XmlInclude(typeof(CreateSerialNumberPayload))]
-    [XmlInclude(typeof(CreateClockConfigurationPayload))]
-    [XmlInclude(typeof(CreateTimestampedWhoAmIPayload))]
-    [XmlInclude(typeof(CreateTimestampedHardwareVersionHighPayload))]
-    [XmlInclude(typeof(CreateTimestampedHardwareVersionLowPayload))]
-    [XmlInclude(typeof(CreateTimestampedAssemblyVersionPayload))]
-    [XmlInclude(typeof(CreateTimestampedCoreVersionHighPayload))]
-    [XmlInclude(typeof(CreateTimestampedCoreVersionLowPayload))]
-    [XmlInclude(typeof(CreateTimestampedFirmwareVersionHighPayload))]
-    [XmlInclude(typeof(CreateTimestampedFirmwareVersionLowPayload))]
-    [XmlInclude(typeof(CreateTimestampedTimestampSecondsPayload))]
-    [XmlInclude(typeof(CreateTimestampedTimestampMicrosecondsPayload))]
-    [XmlInclude(typeof(CreateTimestampedOperationControlPayload))]
-    [XmlInclude(typeof(CreateTimestampedResetDevicePayload))]
-    [XmlInclude(typeof(CreateTimestampedDeviceNamePayload))]
-    [XmlInclude(typeof(CreateTimestampedSerialNumberPayload))]
-    [XmlInclude(typeof(CreateTimestampedClockConfigurationPayload))]
-    [Description("Creates standard message payloads for the Tests device.")]
-    public partial class CreateMessage : CreateMessageBuilder, INamedElement
-    {
-        /// <summary>
-        /// Initializes a new instance of the <see cref="CreateMessage"/> class.
-        /// </summary>
-        public CreateMessage()
-        {
-            Payload = new CreateWhoAmIPayload();
-        }
-
-        string INamedElement.Name => $"{nameof(Tests)}.{GetElementDisplayName(Payload)}";
-    }
-
     /// <summary>
     /// Represents an operator that creates a message payload
     /// that specifies the identity class of the device.
diff --git a/tests/InterfaceGeneratorTests.cs b/tests/InterfaceGeneratorTests.cs
index 4998b8c..af3a5bb 100644
--- a/tests/InterfaceGeneratorTests.cs
+++ b/tests/InterfaceGeneratorTests.cs
@@ -34,7 +34,10 @@ public void DeviceTemplate_GenerateAndBuildWithoutErrors(string metadataFileName
         {
             CompilerTestHelper.CompileFromSource(implementation.Device, implementation.AsyncDevice, payloadExtensions, customImplementation);
             TestHelper.AssertExpectedOutput(implementation.Device, deviceOutputFileName);
-            TestHelper.AssertExpectedOutput(implementation.AsyncDevice, asyncDeviceOutputFileName);
+            if (deviceMetadata.IsApplicationDevice)
+                TestHelper.AssertExpectedOutput(implementation.AsyncDevice, asyncDeviceOutputFileName);
+            else
+                Assert.AreEqual(string.Empty, implementation.AsyncDevice, "Metadata describing only common registers should generate no asynchronous interface.");
         }
         catch (AssertFailedException)
         {