diff --git a/Generator.Tests/PietMethodGeneratorTests.cs b/Generator.Tests/PietMethodGeneratorTests.cs
index 68e8f6e..b079fb0 100644
--- a/Generator.Tests/PietMethodGeneratorTests.cs
+++ b/Generator.Tests/PietMethodGeneratorTests.cs
@@ -1617,7 +1617,12 @@ public partial class Sample
                 .FirstOrDefault(static t => t.Contains("partial class Sample")) ?? string.Empty;
 
             Assert.Contains("public static partial", generatedMethod, "Expected static modifier was not found.");
-            Assert.DoesNotContain("namespace ", generatedMethod, "Global namespace method should not emit a namespace declaration.");
+            // The runtime is appended after the method code in the combined file; extract only the method section.
+            const string runtimeSeparator = "\nnamespace Esolang.Piet.__Generated";
+            var methodSection = generatedMethod.Contains(runtimeSeparator)
+                ? generatedMethod[..generatedMethod.IndexOf(runtimeSeparator, StringComparison.Ordinal)]
+                : generatedMethod;
+            Assert.DoesNotContain("namespace ", methodSection, "Global namespace method should not emit a namespace declaration.");
         }
         catch (Exception e) when (e is AssertFailedException or TargetInvocationException)
         {
diff --git a/Generator/MethodGenerator.Runtime.cs b/Generator/MethodGenerator.Runtime.cs
index 0ecfabd..ac6eb6a 100644
--- a/Generator/MethodGenerator.Runtime.cs
+++ b/Generator/MethodGenerator.Runtime.cs
@@ -1,3 +1,4 @@
+using Microsoft.CodeAnalysis.CSharp;
 using System.Text;
 
 namespace Esolang.Piet.Generator;
@@ -7,7 +8,7 @@ partial class MethodGenerator
     /// <summary>
     /// The generated file name for the shared Piet interpreter runtime.
     /// </summary>
-    public const string GeneratePietRuntimeFileName = "PietRuntime.g.cs";
+    public const string GeneratePietRuntimeFileName = GeneratedMethodsFileName;
 
     /// <summary>
     /// The features that may be needed by the generated methods.
@@ -40,12 +41,10 @@ enum GeneratorFeatures
     /// <summary>
     /// Tries to generate the source code for the shared Piet interpreter runtime if needed.
     /// </summary>
-    static bool TryMakePietRuntimeSource(GeneratorFeatures features, out string filename, out string source)
+    static void AppendPietRuntimeSource(GeneratorFeatures features, LanguageVersion languageVersion, StringBuilder builder)
     {
-        filename = default!;
-        source = default!;
         if (features == GeneratorFeatures.None)
-            return false;
+            return;
         var enableLogging = (features & GeneratorFeatures.UseLogging) != 0;
         // `logger? = null,` or string.Emtpy
         var withLoggingParameter = enableLogging ? "global::Microsoft.Extensions.Logging.ILogger? logger = null," : string.Empty;
@@ -60,20 +59,13 @@ Func<string, string, string, string> callLogExecuting
 
                 """
                 : static (_, _, _) => string.Empty;
-        var builder = new StringBuilder();
-        builder.AppendLine("""
-        // <auto-generated/>
-        #nullable enable
-        #pragma warning disable CS1591
-        using System;
-        using System.ComponentModel;
-        using System.Collections.Generic;
-        using System.Threading;
+        var fileOrInternal = IsLanguageVersionAtLeastCSharp11(languageVersion) ? "file" : "internal";
+        builder.AppendLine($$"""
 
         namespace Esolang.Piet.__Generated
         {
             [EditorBrowsable(EditorBrowsableState.Never)]
-            internal static class PietRuntime
+            {{fileOrInternal}} static class PietRuntime
             {
                 private static readonly int[] s_hue = new int[]
                 {
@@ -912,10 +904,10 @@ internal static async IAsyncEnumerable<byte> ExecuteAsyncEnumerable(
         """);
 
         if ((features & GeneratorFeatures.UseLogging) != 0)
-            builder.AppendLine("""
+            builder.AppendLine($$"""
             
             [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
-            internal static class LoggerUtilities
+            {{fileOrInternal}} static class LoggerUtilities
             {
                 private static readonly global::System.Action<global::Microsoft.Extensions.Logging.ILogger, int, int, int, global::System.Exception?> ExecutingCommand =
                     global::Microsoft.Extensions.Logging.LoggerMessage.Define<int, int, int>(global::Microsoft.Extensions.Logging.LogLevel.Trace, 0, "Executing Piet command: op={Op}, value={Value}, index={Index}");
@@ -934,46 +926,35 @@ public static void LogExecuting(global::Microsoft.Extensions.Logging.ILogger? lo
         }
         """);
 
-        filename = GeneratePietRuntimeFileName;
-        source = builder.ToString();
-        return true;
     }
 
     /// <summary>
     /// The generated file name for the shared Piet++ interpreter runtime.
     /// </summary>
-    public const string GeneratePietPlusPlusRuntimeFileName = "PietPlusPlusRuntime.g.cs";
+    public const string GeneratePietPlusPlusRuntimeFileName = GeneratedMethodsFileName;
 
     /// <summary>
     /// Tries to generate the source code for the shared Piet++ interpreter runtime if needed.
     /// </summary>
-    static bool TryMakePietPlusPlusRuntimeSource(GeneratorFeatures features, out string filename, out string source)
+    static void AppendPietPlusPlusRuntimeSource(GeneratorFeatures features, LanguageVersion languageVersion, StringBuilder builder)
     {
-        filename = default!;
-        source = default!;
         var ppFeatures = features & (GeneratorFeatures.SyncPlusPlus | GeneratorFeatures.AsyncPlusPlus
             | GeneratorFeatures.EnumerablePlusPlus | GeneratorFeatures.AsyncEnumerablePlusPlus);
         if (ppFeatures == GeneratorFeatures.None)
-            return false;
+            return;
 
         var needsSync = (ppFeatures & (GeneratorFeatures.SyncPlusPlus | GeneratorFeatures.EnumerablePlusPlus)) != 0;
         var needsAsync = (ppFeatures & (GeneratorFeatures.AsyncPlusPlus | GeneratorFeatures.AsyncEnumerablePlusPlus)) != 0;
         var needsEnumerable = (ppFeatures & GeneratorFeatures.EnumerablePlusPlus) != 0;
         var needsAsyncEnumerable = (ppFeatures & GeneratorFeatures.AsyncEnumerablePlusPlus) != 0;
 
-        var builder = new StringBuilder();
-        builder.AppendLine("""
-        // <auto-generated/>
-        #nullable enable
-        #pragma warning disable CS1591
-        using System;
-        using System.Collections.Generic;
-        using System.Threading;
+        var fileOrInternal = IsLanguageVersionAtLeastCSharp11(languageVersion) ? "file" : "internal";
+        builder.AppendLine($$"""
 
         namespace Esolang.Piet.__Generated
         {
             [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
-            internal readonly struct PietPlusPlusValue
+            {{fileOrInternal}} readonly struct PietPlusPlusValue
             {
                 readonly int _intVal;
                 readonly List<PietPlusPlusValue>? _stack;
@@ -987,7 +968,7 @@ internal readonly struct PietPlusPlusValue
             }
 
             [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
-            internal static class PietPlusPlusRuntime
+            {{fileOrInternal}} static class PietPlusPlusRuntime
             {
                 private const byte Black = 0;
                 private const byte White = 63;
@@ -1593,8 +1574,5 @@ public static async IAsyncEnumerable<byte> ExecuteAsyncEnumerable(
         }
         """);
 
-        filename = GeneratePietPlusPlusRuntimeFileName;
-        source = builder.ToString();
-        return true;
     }
 }
diff --git a/Generator/MethodGenerator.cs b/Generator/MethodGenerator.cs
index ac3e4f2..c091f0c 100644
--- a/Generator/MethodGenerator.cs
+++ b/Generator/MethodGenerator.cs
@@ -44,7 +44,12 @@ public partial class MethodGenerator : IIncrementalGenerator
         {{CommentAutoGenerated}}
         #nullable enable
         #pragma warning disable CS0219
+        #pragma warning disable CS1591
         #pragma warning disable CS1998
+        using System;
+        using System.ComponentModel;
+        using System.Collections.Generic;
+        using System.Threading;
 
         """;
 
@@ -195,12 +200,10 @@ parseOptions is CSharpParseOptions csharpParseOptions
 
             if (emittedCount > 0)
             {
+                AppendPietRuntimeSource(features, currentLanguageVersion, builder);
+                AppendPietPlusPlusRuntimeSource(features, currentLanguageVersion, builder);
                 context.AddSource(GeneratedMethodsFileName, builder.ToString());
             }
-            if (TryMakePietRuntimeSource(features, out var runtimeFileName, out var runtimeSource))
-                context.AddSource(runtimeFileName, runtimeSource);
-            if (TryMakePietPlusPlusRuntimeSource(features, out var ppRuntimeFileName, out var ppRuntimeSource))
-                context.AddSource(ppRuntimeFileName, ppRuntimeSource);
         });
     }
 
@@ -1194,6 +1197,16 @@ static bool IsLanguageVersionAtLeastCSharp8(LanguageVersion languageVersion)
             _ => languageVersion >= LanguageVersion.CSharp8,
         };
 
+    static bool IsLanguageVersionAtLeastCSharp11(LanguageVersion languageVersion)
+        => languageVersion switch
+        {
+            LanguageVersion.Default => true,
+            LanguageVersion.Latest => true,
+            LanguageVersion.Preview => true,
+            LanguageVersion.LatestMajor => true,
+            _ => languageVersion >= LanguageVersion.CSharp11,
+        };
+
     static AdditionalImageFile? TryResolveImagePath(string imagePath, ImmutableArray<AdditionalImageFile> additionalImageFiles)
     {
         const string dataUrlStarts = "data:";