diff --git a/src/PatternKit.Generators/Builders/BuilderGenerator.cs b/src/PatternKit.Generators/Builders/BuilderGenerator.cs
index 126a7cd0..01b282cc 100644
--- a/src/PatternKit.Generators/Builders/BuilderGenerator.cs
+++ b/src/PatternKit.Generators/Builders/BuilderGenerator.cs
@@ -581,7 +581,11 @@ private static GenerationResult BuildProjection(
             mb.AppendLine();
             if (asyncEnabled)
             {
-                mb.Append("    public static ValueTask<").Append(returnType).Append("> BuildAsync(Func<").Append(builderTypeName).AppendLine(", ValueTask> configure)");
+                var asyncReturnType = IsValueTask(defaultProjector.ReturnType)
+                    ? returnType
+                    : $"ValueTask<{returnType}>";
+
+                mb.Append("    public static ").Append(asyncReturnType).Append(" BuildAsync(Func<").Append(builderTypeName).AppendLine(", ValueTask> configure)");
                 mb.AppendLine("    {");
                 mb.Append("        var builder = ").Append(builderTypeName).Append('.').Append(newMethodName).AppendLine("();");
                 mb.AppendLine("        var pending = configure(builder);");
@@ -599,7 +603,7 @@ private static GenerationResult BuildProjection(
                     mb.Append("        return builder.").Append(buildMethodName).AppendLine("Async();");
                 }
                 mb.AppendLine();
-                mb.Append("        static async ValueTask<").Append(returnType).Append("> AwaitAsync(ValueTask wait, ").Append(builderTypeName).AppendLine(" b)");
+                mb.Append("        static async ").Append(asyncReturnType).Append(" AwaitAsync(ValueTask wait, ").Append(builderTypeName).AppendLine(" b)");
                 mb.AppendLine("        {");
                 mb.AppendLine("            await wait.ConfigureAwait(false);");
                 mb.Append("            return await b.").Append(buildMethodName).AppendLine("Async().ConfigureAwait(false);");
@@ -714,9 +718,8 @@ private static bool IsValueTask(ITypeSymbol type)
             return false;
 
         var constructed = named.ConstructedFrom;
-        var full = constructed.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
-        return string.Equals(full, "global::System.Threading.Tasks.ValueTask<T>", StringComparison.Ordinal) ||
-               string.Equals(full, "global::System.Threading.Tasks.ValueTask", StringComparison.Ordinal);
+        return string.Equals(constructed.Name, "ValueTask", StringComparison.Ordinal) &&
+               string.Equals(constructed.ContainingNamespace.ToDisplayString(), "System.Threading.Tasks", StringComparison.Ordinal);
 
     }
 
diff --git a/src/PatternKit.Generators/DecoratorGenerator.cs b/src/PatternKit.Generators/DecoratorGenerator.cs
index fa6b6afb..9cba58ca 100644
--- a/src/PatternKit.Generators/DecoratorGenerator.cs
+++ b/src/PatternKit.Generators/DecoratorGenerator.cs
@@ -660,9 +660,15 @@ private static string FormatDefaultValue(IParameterSymbol param)
             return $"({enumType.ToDisplayString(TypeFormat)}){param.ExplicitDefaultValue}";
         }
 
-        // Use Roslyn's culture-invariant literal formatting for all other types.
-        return Microsoft.CodeAnalysis.CSharp.SymbolDisplay.FormatPrimitive(param.ExplicitDefaultValue, quoteStrings: true, useHexadecimalNumbers: false)
-            ?? "default";
+        var value = param.ExplicitDefaultValue;
+        return value switch
+        {
+            float f => f.ToString(System.Globalization.CultureInfo.InvariantCulture) + "f",
+            double d => d.ToString(System.Globalization.CultureInfo.InvariantCulture) + "d",
+            decimal m => m.ToString(System.Globalization.CultureInfo.InvariantCulture) + "m",
+            _ => Microsoft.CodeAnalysis.CSharp.SymbolDisplay.FormatPrimitive(value, quoteStrings: true, useHexadecimalNumbers: false)
+                ?? "default"
+        };
     }
 
     private static bool HasAttribute(ISymbol symbol, string attributeName)
diff --git a/test/PatternKit.Generators.Tests/BuilderGeneratorTests.cs b/test/PatternKit.Generators.Tests/BuilderGeneratorTests.cs
index e5200dc2..09de5d58 100644
--- a/test/PatternKit.Generators.Tests/BuilderGeneratorTests.cs
+++ b/test/PatternKit.Generators.Tests/BuilderGeneratorTests.cs
@@ -798,4 +798,81 @@ public static async Task<string> RunAsync()
         var emit = updated.Emit(pe);
         ScenarioExpect.True(emit.Success, string.Join(Environment.NewLine, emit.Diagnostics));
     }
+
+    [Scenario("BuilderDiagnostics CoverNameConflictAndPrivateSetter")]
+    [Fact]
+    public void BuilderDiagnostics_CoverNameConflictAndPrivateSetter()
+    {
+        const string source = """
+            using PatternKit.Generators.Builders;
+
+            namespace PatternKit.Examples.Builders;
+
+            public sealed class ConflictingBuilder
+            {
+            }
+
+            [GenerateBuilder(BuilderTypeName = "ConflictingBuilder")]
+            public partial class Conflicting
+            {
+                public string? Name { get; set; }
+            }
+
+            [GenerateBuilder]
+            public partial class PrivateSetterSample
+            {
+                public string? Name { get; private set; }
+                public int Count { get; set; }
+            }
+            """;
+
+        var comp = RoslynTestHelpers.CreateCompilation(source, nameof(BuilderDiagnostics_CoverNameConflictAndPrivateSetter));
+        var gen = new BuilderGenerator();
+        _ = RoslynTestHelpers.Run(comp, gen, out var run, out _);
+
+        var diagnostics = run.Results.SelectMany(r => r.Diagnostics).ToArray();
+        ScenarioExpect.Contains(diagnostics, diagnostic => diagnostic.Id == "B002");
+        ScenarioExpect.Contains(diagnostics, diagnostic => diagnostic.Id == "B005" && diagnostic.GetMessage().Contains("Name"));
+    }
+
+    [Scenario("StateProjectionBuilder GeneratesValueTaskDefaultProjectorPath")]
+    [Fact]
+    public void StateProjectionBuilder_GeneratesValueTaskDefaultProjectorPath()
+    {
+        const string source = """
+            using System.Threading.Tasks;
+            using PatternKit.Generators.Builders;
+
+            namespace PatternKit.Examples.Builders;
+
+            public readonly record struct AsyncState(string Name);
+            public sealed record AsyncDto(string Name);
+
+            [GenerateBuilder(Model = BuilderModel.StateProjection, GenerateBuilderMethods = true)]
+            public static partial class AsyncProjectionHost
+            {
+                public static AsyncState Seed() => default;
+
+                [BuilderProjector]
+                public static ValueTask<AsyncDto> ProjectAsync(AsyncState state)
+                    => new(new AsyncDto(state.Name ?? ""));
+            }
+            """;
+
+        var comp = RoslynTestHelpers.CreateCompilation(source, nameof(StateProjectionBuilder_GeneratesValueTaskDefaultProjectorPath));
+        var gen = new BuilderGenerator();
+        _ = RoslynTestHelpers.Run(comp, gen, out var run, out var updated);
+
+        ScenarioExpect.All(run.Results, r => ScenarioExpect.Empty(r.Diagnostics));
+
+        var generatedSource = string.Join(Environment.NewLine, run.Results
+            .SelectMany(r => r.GeneratedSources)
+            .Select(source => source.SourceText.ToString()));
+
+        ScenarioExpect.Contains("public ValueTask<global::PatternKit.Examples.Builders.AsyncDto> BuildAsync()", generatedSource);
+        ScenarioExpect.Contains("AsyncProjectionHost.ProjectAsync(state)", generatedSource);
+
+        var emit = updated.Emit(Stream.Null);
+        ScenarioExpect.True(emit.Success, string.Join(Environment.NewLine, emit.Diagnostics));
+    }
 }
diff --git a/test/PatternKit.Generators.Tests/ComposerGeneratorTests.cs b/test/PatternKit.Generators.Tests/ComposerGeneratorTests.cs
index 1cd32f54..369aa9f8 100644
--- a/test/PatternKit.Generators.Tests/ComposerGeneratorTests.cs
+++ b/test/PatternKit.Generators.Tests/ComposerGeneratorTests.cs
@@ -1077,4 +1077,38 @@ private Task<Response> TerminalAsync(Request req, CancellationToken ct)
         var emit = updated.Emit(Stream.Null);
         ScenarioExpect.True(emit.Success, string.Join("\n", emit.Diagnostics));
     }
+
+    [Scenario("InvalidStep WithNonFuncNext ReportsDiagnostic")]
+    [Fact]
+    public void InvalidStep_WithNonFuncNext_ReportsDiagnostic()
+    {
+        var source = """
+            using PatternKit.Generators.Composer;
+
+            public readonly record struct Request(string Path);
+            public readonly record struct Response(int Status);
+
+            public delegate Response RequestDelegate(Request request);
+
+            [Composer]
+            public partial class RequestPipeline
+            {
+                [ComposeStep(0)]
+                private Response Step(in Request req, RequestDelegate next)
+                    => next(req);
+
+                [ComposeTerminal]
+                private Response Terminal(in Request req)
+                    => new(200);
+            }
+            """;
+
+        var comp = RoslynTestHelpers.CreateCompilation(source, nameof(InvalidStep_WithNonFuncNext_ReportsDiagnostic));
+        var gen = new ComposerGenerator();
+        _ = RoslynTestHelpers.Run(comp, gen, out var result, out _);
+
+        var diagnostic = ScenarioExpect.Single(result.Results.SelectMany(r => r.Diagnostics));
+        ScenarioExpect.Equal("PKCOM006", diagnostic.Id);
+        ScenarioExpect.Contains("Step", diagnostic.GetMessage(), StringComparison.Ordinal);
+    }
 }
diff --git a/test/PatternKit.Generators.Tests/DecoratorGeneratorTests.cs b/test/PatternKit.Generators.Tests/DecoratorGeneratorTests.cs
index 4a03e9fa..d1c3f68c 100644
--- a/test/PatternKit.Generators.Tests/DecoratorGeneratorTests.cs
+++ b/test/PatternKit.Generators.Tests/DecoratorGeneratorTests.cs
@@ -1160,4 +1160,50 @@ public class NestedType
         ScenarioExpect.Contains(diagnostics, d => d.Id == "PKDEC002" && d.GetMessage().Contains("Field"));
         ScenarioExpect.Contains(diagnostics, d => d.Id == "PKDEC002" && d.GetMessage().Contains("NestedType"));
     }
+
+    [Scenario("GenerateDecorator PreservesPrimitiveAndStringDefaultLiterals")]
+    [Fact]
+    public void GenerateDecorator_PreservesPrimitiveAndStringDefaultLiterals()
+    {
+        const string source = """
+            using PatternKit.Generators.Decorator;
+
+            namespace TestNamespace;
+
+            public enum Mode { None = 0, Known = 1 }
+
+            [GenerateDecorator]
+            public interface ILiteralService
+            {
+                string Format(
+                    string text = "line\n\"quoted\"\tend",
+                    bool enabled = true,
+                    float ratio = 1.25f,
+                    double weight = 2.5d,
+                    decimal amount = 3.75m,
+                    Mode mode = (Mode)99);
+            }
+            """;
+
+        var comp = RoslynTestHelpers.CreateCompilation(source, nameof(GenerateDecorator_PreservesPrimitiveAndStringDefaultLiterals));
+        var gen = new DecoratorGenerator();
+        _ = RoslynTestHelpers.Run(comp, gen, out var result, out var updated);
+
+        ScenarioExpect.All(result.Results, r => ScenarioExpect.Empty(r.Diagnostics));
+
+        var generatedSource = result.Results
+            .SelectMany(r => r.GeneratedSources)
+            .First(gs => gs.HintName == "TestNamespace_ILiteralService.Decorator.g.cs")
+            .SourceText.ToString();
+
+        ScenarioExpect.Contains("string text = \"line\\n\\\"quoted\\\"\\tend\"", generatedSource);
+        ScenarioExpect.Contains("bool enabled = true", generatedSource);
+        ScenarioExpect.Contains("float ratio = 1.25f", generatedSource);
+        ScenarioExpect.Contains("double weight = 2.5d", generatedSource);
+        ScenarioExpect.Contains("decimal amount = 3.75m", generatedSource);
+        ScenarioExpect.Contains("global::TestNamespace.Mode mode = (global::TestNamespace.Mode)99", generatedSource);
+
+        var emit = updated.Emit(Stream.Null);
+        ScenarioExpect.True(emit.Success, string.Join("\n", emit.Diagnostics));
+    }
 }
diff --git a/test/PatternKit.Generators.Tests/ProxyGeneratorTests.cs b/test/PatternKit.Generators.Tests/ProxyGeneratorTests.cs
index e1715d22..291682ad 100644
--- a/test/PatternKit.Generators.Tests/ProxyGeneratorTests.cs
+++ b/test/PatternKit.Generators.Tests/ProxyGeneratorTests.cs
@@ -1487,4 +1487,48 @@ string Format(
         var emit = updated.Emit(Stream.Null);
         ScenarioExpect.True(emit.Success, string.Join("\n", emit.Diagnostics));
     }
+
+    [Scenario("GenerateProxy Defaults CoverPrimitiveStringAndNumericBranches")]
+    [Fact]
+    public void GenerateProxy_Defaults_CoverPrimitiveStringAndNumericBranches()
+    {
+        const string source = """
+            using PatternKit.Generators.Proxy;
+
+            namespace TestNamespace;
+
+            [GenerateProxy(InterceptorMode = ProxyInterceptorMode.None)]
+            public partial interface ILiteralProxy
+            {
+                string Format(
+                    string text = "line\n\"quoted\"\tend",
+                    bool enabled = true,
+                    float ratio = 1.25f,
+                    double weight = 2.5d,
+                    decimal amount = 3.75m,
+                    char apostrophe = '\'');
+            }
+            """;
+
+        var comp = RoslynTestHelpers.CreateCompilation(source, nameof(GenerateProxy_Defaults_CoverPrimitiveStringAndNumericBranches));
+        var gen = new ProxyGenerator();
+        _ = RoslynTestHelpers.Run(comp, gen, out var result, out var updated);
+
+        ScenarioExpect.All(result.Results, r => ScenarioExpect.Empty(r.Diagnostics));
+
+        var proxySource = result.Results
+            .SelectMany(r => r.GeneratedSources)
+            .Single(gs => gs.HintName == "TestNamespace_ILiteralProxy.Proxy.g.cs")
+            .SourceText.ToString();
+
+        ScenarioExpect.Contains("string text = \"line\\n\\\"quoted\\\"\\tend\"", proxySource);
+        ScenarioExpect.Contains("bool enabled = true", proxySource);
+        ScenarioExpect.Contains("float ratio = 1.25f", proxySource);
+        ScenarioExpect.Contains("double weight = 2.5d", proxySource);
+        ScenarioExpect.Contains("decimal amount = 3.75m", proxySource);
+        ScenarioExpect.Contains("char apostrophe = '\\''", proxySource);
+
+        var emit = updated.Emit(Stream.Null);
+        ScenarioExpect.True(emit.Success, string.Join("\n", emit.Diagnostics));
+    }
 }