fix: handle nullable numeric types in gRPC request mapping

When a C# property is nullable (int?, long?, etc.), protobuf3 defaults
to 0 when the field is not set. The generator now treats 0 as null
for nullable numeric properties, allowing proper optional field semantics.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Svrnty.CQRS.Grpc.Generators/GrpcGenerator.cs

@@ -350,6 +350,7 @@ namespace Svrnty.CQRS.Grpc.Generators
                 var propInfo = new PropertyInfo
                 {
                     Name = property.Name,
+                    ProtoPropertyName = ToPascalCaseHelper(ToSnakeCaseHelper(property.Name)),
                     Type = propertyType,
                     FullyQualifiedType = propertyType,
                     ProtoType = protoType,
@@ -507,6 +508,7 @@ namespace Svrnty.CQRS.Grpc.Generators
                 var propInfo = new PropertyInfo
                 {
                     Name = property.Name,
+                    ProtoPropertyName = ToPascalCaseHelper(ToSnakeCaseHelper(property.Name)),
                     Type = propertyType,
                     FullyQualifiedType = propertyType,
                     ProtoType = string.Empty,
@@ -536,6 +538,7 @@ namespace Svrnty.CQRS.Grpc.Generators
                 var propInfo = new PropertyInfo
                 {
                     Name = property.Name,
+                    ProtoPropertyName = ToPascalCaseHelper(ToSnakeCaseHelper(property.Name)),
                     Type = propertyType,
                     FullyQualifiedType = propertyType,
                     ProtoType = string.Empty,
@@ -577,26 +580,26 @@ namespace Svrnty.CQRS.Grpc.Generators
         {
             foreach (var prop in properties)
             {
-                var sourcePropName = char.ToUpper(prop.Name[0]) + prop.Name.Substring(1);
+                // Use ProtoPropertyName to access the proto source property
                 if (prop.IsComplexType)
                 {
                     // Generate nested object mapping
-                    sb.AppendLine($"{indent}{prop.Name} = {sourcePrefix}.{sourcePropName} != null ? new {prop.FullyQualifiedType}");
+                    sb.AppendLine($"{indent}{prop.Name} = {sourcePrefix}.{prop.ProtoPropertyName} != null ? new {prop.FullyQualifiedType}");
                     sb.AppendLine($"{indent}{{");
-                    GenerateNestedPropertyMapping(sb, prop.NestedProperties, $"{sourcePrefix}.{sourcePropName}", indent + "    ");
+                    GenerateNestedPropertyMapping(sb, prop.NestedProperties, $"{sourcePrefix}.{prop.ProtoPropertyName}", indent + "    ");
                     sb.AppendLine($"{indent}}} : null!,");
                 }
                 else
                 {
-                    sb.AppendLine($"{indent}{prop.Name} = {sourcePrefix}.{sourcePropName},");
+                    sb.AppendLine($"{indent}{prop.Name} = {sourcePrefix}.{prop.ProtoPropertyName},");
                 }
             }
         }
 
         private static string GeneratePropertyAssignment(PropertyInfo prop, string requestVar, string indent)
         {
-            var requestPropName = char.ToUpper(prop.Name[0]) + prop.Name.Substring(1);
-            var source = $"{requestVar}.{requestPropName}";
+            // Use ProtoPropertyName to access the proto request property
+            var source = $"{requestVar}.{prop.ProtoPropertyName}";
 
             // Handle lists
             if (prop.IsList)
@@ -663,7 +666,7 @@ namespace Svrnty.CQRS.Grpc.Generators
 
             foreach (var nestedProp in prop.ElementNestedProperties!)
             {
-                var nestedSourcePropName = char.ToUpper(nestedProp.Name[0]) + nestedProp.Name.Substring(1);
+                // Use ProtoPropertyName for accessing proto source properties
                 var nestedAssignment = GenerateNestedPropertyAssignment(nestedProp, "x", indent + "    ");
                 sb.AppendLine(nestedAssignment);
             }
@@ -690,8 +693,8 @@ namespace Svrnty.CQRS.Grpc.Generators
 
         private static string GenerateNestedPropertyAssignment(PropertyInfo prop, string sourceVar, string indent)
         {
-            var sourcePropName = char.ToUpper(prop.Name[0]) + prop.Name.Substring(1);
-            var source = $"{sourceVar}.{sourcePropName}";
+            // Use ProtoPropertyName to access the proto source property
+            var source = $"{sourceVar}.{prop.ProtoPropertyName}";
 
             // Handle enums
             if (prop.IsEnum)
@@ -750,27 +753,112 @@ namespace Svrnty.CQRS.Grpc.Generators
             var resultTypeString = resultType.ToDisplayString();
             queryInfo.IsResultPrimitiveType = IsPrimitiveType(resultTypeString);
 
-            // Extract result type properties if it's a complex type
-            if (!queryInfo.IsResultPrimitiveType)
+            // Check if result type is nullable and compute non-nullable name
+            var isNullable = resultType.NullableAnnotation == NullableAnnotation.Annotated ||
+                             resultTypeString.EndsWith("?");
+            queryInfo.IsResultNullable = isNullable;
+
+            // Use the short type name (without namespace) for proto type mapping
+            // This matches how ResultElementType is used for collections
+            var shortTypeName = resultType.Name;
+            if (shortTypeName.EndsWith("?"))
             {
-                var resultProperties = resultType.GetMembers().OfType<IPropertySymbol>()
+                queryInfo.ResultTypeWithoutNullable = shortTypeName.Substring(0, shortTypeName.Length - 1);
+            }
+            else
+            {
+                queryInfo.ResultTypeWithoutNullable = shortTypeName;
+            }
+
+            // Check if result type is a collection and extract element type
+            var (isCollection, elementType) = GetCollectionElementType(resultType);
+            queryInfo.IsResultCollection = isCollection;
+
+            // Determine which type to extract properties from
+            INamedTypeSymbol? typeToExtractFrom = null;
+            if (isCollection && elementType != null)
+            {
+                queryInfo.ResultElementType = elementType.Name;
+                queryInfo.ResultElementTypeFullyQualified = elementType.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
+                typeToExtractFrom = elementType;
+            }
+            else if (!queryInfo.IsResultPrimitiveType && resultType is INamedTypeSymbol namedType)
+            {
+                typeToExtractFrom = namedType;
+            }
+
+            // Extract result type properties if it's a complex type (or collection of complex type)
+            if (typeToExtractFrom != null)
+            {
+                var resultProperties = typeToExtractFrom.GetMembers().OfType<IPropertySymbol>()
                     .Where(p => p.DeclaredAccessibility == Accessibility.Public && !p.IsStatic)
                     .ToList();
 
                 foreach (var property in resultProperties)
                 {
+                    var propType = property.Type;
+                    var propTypeStr = propType.ToDisplayString();
+
+                    // Check for type categories
+                    var isEnum = propType.TypeKind == TypeKind.Enum;
+                    var isDecimal = propTypeStr == "decimal" || propTypeStr == "System.Decimal" ||
+                                    propTypeStr == "decimal?" || propTypeStr == "System.Nullable<System.Decimal>";
+                    var isDateTime = propTypeStr.Contains("DateTime") || propTypeStr.Contains("DateTimeOffset");
+                    var isPropNullable = propType.NullableAnnotation == NullableAnnotation.Annotated ||
+                                     propTypeStr.EndsWith("?") ||
+                                     propTypeStr.StartsWith("System.Nullable<");
+                    var isString = propTypeStr == "string" || propTypeStr == "System.String" ||
+                                   propTypeStr == "string?" || propTypeStr == "System.String?";
+
+                    // Check if property is a collection
+                    var (isPropCollection, propElementType) = GetCollectionElementType(propType);
+                    var isElementComplexType = false;
+                    List<PropertyInfo>? elementNestedProperties = null;
+
+                    if (isPropCollection && propElementType != null)
+                    {
+                        isElementComplexType = propElementType.TypeKind != TypeKind.Enum &&
+                                               !IsPrimitiveType(propElementType.ToDisplayString());
+                        if (isElementComplexType)
+                        {
+                            elementNestedProperties = new List<PropertyInfo>();
+                            ExtractNestedPropertiesWithTypeInfo(propElementType, elementNestedProperties);
+                        }
+                    }
+
+                    // Check if property itself is a complex type
+                    var isComplexType = !isEnum && !isPropCollection &&
+                                        !IsPrimitiveType(propTypeStr.TrimEnd('?'));
+                    List<PropertyInfo>? nestedProperties = null;
+                    if (isComplexType && propType is INamedTypeSymbol namedPropType)
+                    {
+                        nestedProperties = new List<PropertyInfo>();
+                        ExtractNestedPropertiesWithTypeInfo(namedPropType, nestedProperties);
+                    }
+
                     queryInfo.ResultProperties.Add(new PropertyInfo
                     {
                         Name = property.Name,
-                        Type = property.Type.ToDisplayString(),
-                        FullyQualifiedType = property.Type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat),
+                        ProtoPropertyName = ToPascalCaseHelper(ToSnakeCaseHelper(property.Name)),
+                        Type = propTypeStr,
+                        FullyQualifiedType = propType.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat),
                         ProtoType = string.Empty, // Not needed for result mapping
-                        FieldNumber = 0 // Not needed for result mapping
+                        FieldNumber = 0, // Not needed for result mapping
+                        IsEnum = isEnum,
+                        IsDecimal = isDecimal,
+                        IsDateTime = isDateTime,
+                        IsNullable = isPropNullable || isString, // Treat strings as nullable for null-coalescing
+                        IsList = isPropCollection,
+                        IsComplexType = isComplexType,
+                        NestedProperties = nestedProperties ?? new List<PropertyInfo>(),
+                        ElementType = propElementType?.ToDisplayString(),
+                        IsElementComplexType = isElementComplexType,
+                        ElementNestedProperties = elementNestedProperties
                     });
                 }
             }
 
-            // Extract properties
+            // Extract properties with type metadata for request mapping
             var properties = queryType.GetMembers().OfType<IPropertySymbol>()
                 .Where(p => p.DeclaredAccessibility == Accessibility.Public && !p.IsStatic)
                 .ToList();
@@ -779,14 +867,30 @@ namespace Svrnty.CQRS.Grpc.Generators
             foreach (var property in properties)
             {
                 var propertyType = property.Type.ToDisplayString(SymbolDisplayFormat.FullyQualifiedFormat);
+                var propertyTypeShort = property.Type.ToDisplayString();
                 var protoType = ProtoTypeMapper.MapToProtoType(propertyType, out bool isRepeated, out bool isOptional);
 
+                // Determine type metadata for proper request mapping
+                var isEnum = property.Type.TypeKind == TypeKind.Enum;
+                var isDecimal = propertyTypeShort == "decimal" || propertyTypeShort == "System.Decimal" ||
+                                propertyTypeShort == "decimal?" || propertyTypeShort.Contains("Nullable<System.Decimal>");
+                var isDateTime = propertyTypeShort.Contains("DateTime") || propertyTypeShort.Contains("DateTimeOffset");
+                var isRequestPropNullable = property.Type.NullableAnnotation == NullableAnnotation.Annotated ||
+                                 propertyTypeShort.EndsWith("?") ||
+                                 propertyTypeShort.StartsWith("System.Nullable<");
+
                 queryInfo.Properties.Add(new PropertyInfo
                 {
                     Name = property.Name,
+                    ProtoPropertyName = ToPascalCaseHelper(ToSnakeCaseHelper(property.Name)),
                     Type = propertyType,
+                    FullyQualifiedType = propertyType,
                     ProtoType = protoType,
-                    FieldNumber = fieldNumber++
+                    FieldNumber = fieldNumber++,
+                    IsEnum = isEnum,
+                    IsDecimal = isDecimal,
+                    IsDateTime = isDateTime,
+                    IsNullable = isRequestPropNullable
                 });
             }
 
@@ -1579,6 +1683,7 @@ namespace Svrnty.CQRS.Grpc.Generators
             sb.AppendLine("#nullable enable");
             sb.AppendLine("using Grpc.Core;");
             sb.AppendLine("using System.Threading.Tasks;");
+            sb.AppendLine("using System.Linq;");
             sb.AppendLine("using Microsoft.Extensions.DependencyInjection;");
             sb.AppendLine($"using {rootNamespace}.Grpc;");
             sb.AppendLine("using Svrnty.CQRS.Abstractions;");
@@ -1617,29 +1722,130 @@ namespace Svrnty.CQRS.Grpc.Generators
                 sb.AppendLine("            {");
                 foreach (var prop in query.Properties)
                 {
-                    sb.AppendLine($"                {prop.Name} = request.{char.ToUpper(prop.Name[0]) + prop.Name.Substring(1)},");
+                    var requestMapping = GenerateRequestPropertyMapping(prop);
+                    sb.AppendLine($"                {prop.Name} = {requestMapping},");
                 }
                 sb.AppendLine("            };");
                 sb.AppendLine("            var result = await handler.HandleAsync(query, context.CancellationToken);");
 
-                // Generate response with mapping if complex type
+                // Generate response with mapping based on result type
                 if (query.IsResultPrimitiveType)
                 {
                     sb.AppendLine($"            return new {responseType} {{ Result = result }};");
                 }
-                else
+                else if (query.IsResultCollection)
                 {
-                    // Complex type - need to map from C# type to proto type
-                    sb.AppendLine($"            return new {responseType}");
+                    // Collection result - use AddRange with LINQ Select for type conversion
+                    var elementTypeName = query.ResultElementType;
+                    sb.AppendLine($"            var response = new {responseType}();");
+                    sb.AppendLine($"            response.Result.AddRange(result.Select(item => new {elementTypeName}");
                     sb.AppendLine("            {");
-                    sb.AppendLine($"                Result = new {query.ResultType}");
-                    sb.AppendLine("                {");
                     foreach (var prop in query.ResultProperties)
                     {
-                        sb.AppendLine($"                    {prop.Name} = result.{prop.Name},");
+                        // Skip collection properties (they need separate AddRange handling, not supported in collection results)
+                        if (prop.IsList) continue;
+
+                        var mapping = GeneratePropertyMapping("item", prop);
+                        if (mapping != null)
+                        {
+                            sb.AppendLine($"                {prop.ProtoPropertyName} = {mapping},");
+                        }
+                    }
+                    sb.AppendLine("            }));");
+                    sb.AppendLine("            return response;");
+                }
+                else
+                {
+                    // Single complex object - map properties with type conversions
+                    // Use the non-nullable type name for the proto message
+                    var protoResultType = query.ResultTypeWithoutNullable;
+
+                    if (query.IsResultNullable)
+                    {
+                        // Handle nullable result - check for null and return empty response
+                        sb.AppendLine("            if (result == null)");
+                        sb.AppendLine("            {");
+                        sb.AppendLine($"                return new {responseType}();");
+                        sb.AppendLine("            }");
+                        sb.AppendLine();
+                    }
+
+                    // Separate simple properties from collection properties
+                    var simpleProps = query.ResultProperties.Where(p => !p.IsList).ToList();
+                    var collectionProps = query.ResultProperties.Where(p => p.IsList).ToList();
+
+                    if (collectionProps.Count == 0)
+                    {
+                        // No collection properties - simple case
+                        sb.AppendLine($"            return new {responseType}");
+                        sb.AppendLine("            {");
+                        sb.AppendLine($"                Result = new {protoResultType}");
+                        sb.AppendLine("                {");
+                        foreach (var prop in simpleProps)
+                        {
+                            var mapping = GeneratePropertyMapping("result", prop);
+                            sb.AppendLine($"                    {prop.ProtoPropertyName} = {mapping},");
+                        }
+                        sb.AppendLine("                }");
+                        sb.AppendLine("            };");
+                    }
+                    else
+                    {
+                        // Has collection properties - need to use AddRange
+                        sb.AppendLine($"            var protoResult = new {protoResultType}");
+                        sb.AppendLine("            {");
+                        foreach (var prop in simpleProps)
+                        {
+                            var mapping = GeneratePropertyMapping("result", prop);
+                            sb.AppendLine($"                {prop.ProtoPropertyName} = {mapping},");
+                        }
+                        sb.AppendLine("            };");
+                        sb.AppendLine();
+
+                        // Add collection properties with AddRange
+                        foreach (var prop in collectionProps)
+                        {
+                            var elementTypeName = prop.ElementType;
+                            if (!string.IsNullOrEmpty(elementTypeName))
+                            {
+                                var lastDot = elementTypeName.LastIndexOf('.');
+                                if (lastDot >= 0)
+                                {
+                                    elementTypeName = elementTypeName.Substring(lastDot + 1);
+                                }
+                            }
+
+                            if (prop.IsElementComplexType && prop.ElementNestedProperties != null && prop.ElementNestedProperties.Count > 0)
+                            {
+                                // Complex element type - map properties
+                                sb.AppendLine($"            if (result.{prop.Name} != null)");
+                                sb.AppendLine("            {");
+                                sb.AppendLine($"                protoResult.{prop.ProtoPropertyName}.AddRange(result.{prop.Name}.Select(item => new {elementTypeName}");
+                                sb.AppendLine("                {");
+                                foreach (var nestedProp in prop.ElementNestedProperties)
+                                {
+                                    var nestedMapping = GeneratePropertyMapping("item", nestedProp);
+                                    if (nestedMapping != null)
+                                    {
+                                        sb.AppendLine($"                    {nestedProp.ProtoPropertyName} = {nestedMapping},");
+                                    }
+                                }
+                                sb.AppendLine("                }));");
+                                sb.AppendLine("            }");
+                            }
+                            else
+                            {
+                                // Simple element type or no nested properties - direct copy
+                                sb.AppendLine($"            if (result.{prop.Name} != null)");
+                                sb.AppendLine("            {");
+                                sb.AppendLine($"                protoResult.{prop.ProtoPropertyName}.AddRange(result.{prop.Name});");
+                                sb.AppendLine("            }");
+                            }
+                            sb.AppendLine();
+                        }
+
+                        sb.AppendLine($"            return new {responseType} {{ Result = protoResult }};");
                     }
-                    sb.AppendLine("                }");
-                    sb.AppendLine("            };");
                 }
 
                 sb.AppendLine("        }");
@@ -1672,9 +1878,231 @@ namespace Svrnty.CQRS.Grpc.Generators
                 "System.Guid"
             };
 
-            return primitiveTypes.Contains(typeName) ||
-                   typeName.StartsWith("System.Nullable<") ||
-                   typeName.EndsWith("?");
+            // Handle nullable types - extract the underlying type first
+            var typeToCheck = typeName;
+            if (typeName.EndsWith("?"))
+            {
+                typeToCheck = typeName.Substring(0, typeName.Length - 1);
+            }
+            else if (typeName.StartsWith("System.Nullable<") && typeName.EndsWith(">"))
+            {
+                typeToCheck = typeName.Substring("System.Nullable<".Length, typeName.Length - "System.Nullable<".Length - 1);
+            }
+
+            return primitiveTypes.Contains(typeToCheck);
+        }
+
+        /// <summary>
+        /// Generates the mapping expression for a property from C# domain type to proto type
+        /// </summary>
+        private static string GeneratePropertyMapping(string sourceVar, PropertyInfo prop)
+        {
+            var accessor = $"{sourceVar}.{prop.Name}";
+
+            // Handle decimal → string conversion
+            if (prop.IsDecimal)
+            {
+                if (prop.IsNullable)
+                    return $"{accessor}?.ToString() ?? \"\"";
+                return $"{accessor}.ToString()";
+            }
+
+            // Handle DateTime/DateTimeOffset → string conversion
+            if (prop.IsDateTime)
+            {
+                if (prop.IsNullable)
+                    return $"{accessor}?.ToString(\"O\") ?? \"\"";
+                return $"{accessor}.ToString(\"O\")";
+            }
+
+            // Handle enum → proto enum conversion (cast with same underlying value)
+            if (prop.IsEnum)
+            {
+                // Extract just the enum name (without namespace) for the proto enum type
+                var enumTypeName = prop.Type;
+                var lastDot = enumTypeName.LastIndexOf('.');
+                if (lastDot >= 0)
+                {
+                    enumTypeName = enumTypeName.Substring(lastDot + 1);
+                }
+                // Remove nullable suffix if present
+                if (enumTypeName.EndsWith("?"))
+                {
+                    enumTypeName = enumTypeName.Substring(0, enumTypeName.Length - 1);
+                }
+                return $"({enumTypeName})(int){accessor}";
+            }
+
+            // Handle collection properties - these need special handling with AddRange
+            if (prop.IsList)
+            {
+                // Return a special marker indicating this needs AddRange treatment
+                return null;
+            }
+
+            // Handle nullable strings with null coalescing
+            if (prop.IsNullable && (prop.Type.Contains("string") || prop.Type == "string" || prop.Type == "string?"))
+            {
+                return $"{accessor} ?? \"\"";
+            }
+
+            // Handle collections (nested repeated fields)
+            if (prop.IsList && prop.IsElementComplexType && prop.ElementNestedProperties != null)
+            {
+                var sb = new StringBuilder();
+                sb.Append($"new global::Google.Protobuf.Collections.RepeatedField<{prop.ElementType}>()");
+                // Note: For nested collections, we'd need to generate AddRange call separately
+                // For now, return the accessor - caller should handle complex cases
+                return accessor;
+            }
+
+            // Handle complex nested types
+            if (prop.IsComplexType && prop.NestedProperties.Count > 0)
+            {
+                var sb = new StringBuilder();
+                sb.Append($"new {prop.Type}");
+                sb.AppendLine();
+                sb.Append("                {");
+                foreach (var nestedProp in prop.NestedProperties)
+                {
+                    var nestedMapping = GeneratePropertyMapping(accessor, nestedProp);
+                    sb.AppendLine();
+                    sb.Append($"                    {nestedProp.ProtoPropertyName} = {nestedMapping},");
+                }
+                sb.AppendLine();
+                sb.Append("                }");
+                return sb.ToString();
+            }
+
+            // Default: direct assignment (works for primitives and simple types)
+            return accessor;
+        }
+
+        /// <summary>
+        /// Generates the mapping expression for a request property from proto type to C# domain type
+        /// </summary>
+        private static string GenerateRequestPropertyMapping(PropertyInfo prop)
+        {
+            // Use the proto property name (computed from snake_case conversion)
+            var accessor = $"request.{prop.ProtoPropertyName}";
+
+            // Handle string → decimal conversion (proto uses string for decimal)
+            if (prop.IsDecimal)
+            {
+                if (prop.IsNullable)
+                    return $"string.IsNullOrEmpty({accessor}) ? null : decimal.Parse({accessor})";
+                return $"decimal.Parse({accessor})";
+            }
+
+            // Handle string → DateTime conversion (proto uses string for DateTime)
+            if (prop.IsDateTime)
+            {
+                if (prop.IsNullable)
+                    return $"string.IsNullOrEmpty({accessor}) ? null : global::System.DateTime.Parse({accessor})";
+                return $"global::System.DateTime.Parse({accessor})";
+            }
+
+            // Handle proto enum → domain enum conversion
+            if (prop.IsEnum)
+            {
+                // Cast from proto enum (int) to domain enum
+                return $"({prop.Type})(int){accessor}";
+            }
+
+            // Handle nullable numeric types (int?, long?, etc.)
+            // In protobuf3, numeric fields default to 0 when not set.
+            // For nullable C# types, we treat 0 as null (unset).
+            if (prop.IsNullable && IsNullableNumericType(prop.Type))
+            {
+                return $"{accessor} == 0 ? null : {accessor}";
+            }
+
+            // Default: direct assignment (works for compatible types like int, long, string, bool)
+            return accessor;
+        }
+
+        /// <summary>
+        /// Checks if the type is a nullable numeric type (int?, long?, short?, etc.)
+        /// </summary>
+        private static bool IsNullableNumericType(string typeName)
+        {
+            // Check for common nullable numeric types
+            var nullableNumericTypes = new[]
+            {
+                "int?", "System.Int32?", "global::System.Int32?",
+                "long?", "System.Int64?", "global::System.Int64?",
+                "short?", "System.Int16?", "global::System.Int16?",
+                "byte?", "System.Byte?", "global::System.Byte?",
+                "uint?", "System.UInt32?", "global::System.UInt32?",
+                "ulong?", "System.UInt64?", "global::System.UInt64?",
+                "ushort?", "System.UInt16?", "global::System.UInt16?",
+                "sbyte?", "System.SByte?", "global::System.SByte?",
+                "float?", "System.Single?", "global::System.Single?",
+                "double?", "System.Double?", "global::System.Double?",
+            };
+            return nullableNumericTypes.Contains(typeName);
+        }
+
+        /// <summary>
+        /// Checks if a type is a collection type and returns the element type if so
+        /// </summary>
+        private static (bool IsCollection, INamedTypeSymbol? ElementType) GetCollectionElementType(ITypeSymbol type)
+        {
+            // Check if it's a named type
+            if (type is not INamedTypeSymbol namedType)
+                return (false, null);
+
+            // Explicitly exclude string (it implements IEnumerable<char> but we don't want to treat it as a collection)
+            var typeDisplayName = type.ToDisplayString();
+            if (typeDisplayName == "string" || typeDisplayName == "System.String" ||
+                typeDisplayName == "string?" || typeDisplayName == "System.String?")
+            {
+                return (false, null);
+            }
+
+            // Check for common collection types: List<T>, IList<T>, IEnumerable<T>, ICollection<T>, T[]
+            var typeFullName = namedType.OriginalDefinition.ToDisplayString();
+
+            // Check for array
+            if (type is IArrayTypeSymbol arrayType)
+            {
+                if (arrayType.ElementType is INamedTypeSymbol arrayElementType)
+                    return (true, arrayElementType);
+                return (true, null);
+            }
+
+            // Collection type patterns to check
+            var collectionPatterns = new[]
+            {
+                "System.Collections.Generic.List<T>",
+                "System.Collections.Generic.IList<T>",
+                "System.Collections.Generic.IEnumerable<T>",
+                "System.Collections.Generic.ICollection<T>",
+                "System.Collections.Generic.IReadOnlyList<T>",
+                "System.Collections.Generic.IReadOnlyCollection<T>"
+            };
+
+            foreach (var pattern in collectionPatterns)
+            {
+                if (typeFullName == pattern && namedType.TypeArguments.Length > 0)
+                {
+                    var elementType = namedType.TypeArguments[0] as INamedTypeSymbol;
+                    return (true, elementType);
+                }
+            }
+
+            // Also check interfaces for types that implement IEnumerable<T>
+            foreach (var iface in namedType.AllInterfaces)
+            {
+                var ifaceFullName = iface.OriginalDefinition.ToDisplayString();
+                if (ifaceFullName == "System.Collections.Generic.IEnumerable<T>" && iface.TypeArguments.Length > 0)
+                {
+                    var elementType = iface.TypeArguments[0] as INamedTypeSymbol;
+                    return (true, elementType);
+                }
+            }
+
+            return (false, null);
         }
 
         private static string GenerateDynamicQueryMessages(List<DynamicQueryInfo> dynamicQueries, string rootNamespace)
@@ -2232,6 +2660,7 @@ namespace Svrnty.CQRS.Grpc.Generators
                     properties.Add(new PropertyInfo
                     {
                         Name = prop.Name,
+                        ProtoPropertyName = ToPascalCaseHelper(ToSnakeCaseHelper(prop.Name)),
                         Type = propType,
                         FullyQualifiedType = propType,
                         ProtoType = protoType,
@@ -2382,8 +2811,27 @@ namespace Svrnty.CQRS.Grpc.Generators
         {
             if (string.IsNullOrEmpty(snakeCase)) return snakeCase;
             var parts = snakeCase.Split('_');
-            return string.Join("", parts.Select(p =>
-                p.Length > 0 ? char.ToUpperInvariant(p[0]) + p.Substring(1).ToLowerInvariant() : ""));
+            var result = new StringBuilder();
+            foreach (var part in parts)
+            {
+                if (part.Length == 0) continue;
+                // Capitalize the first letter
+                result.Append(char.ToUpperInvariant(part[0]));
+                // Process remaining characters - capitalize letters that follow digits
+                for (int i = 1; i < part.Length; i++)
+                {
+                    char c = part[i];
+                    if (i > 0 && char.IsLetter(c) && char.IsDigit(part[i - 1]))
+                    {
+                        result.Append(char.ToUpperInvariant(c));
+                    }
+                    else
+                    {
+                        result.Append(char.ToLowerInvariant(c));
+                    }
+                }
+            }
+            return result.ToString();
         }
     }
 }

Svrnty.CQRS.Grpc.Generators/Models/CommandInfo.cs

@@ -31,6 +31,11 @@ namespace Svrnty.CQRS.Grpc.Generators.Models
     public class PropertyInfo
     {
         public string Name { get; set; }
+        /// <summary>
+        /// The property name as generated by Grpc.Tools from the proto field name.
+        /// This may differ from the C# property name due to casing differences.
+        /// </summary>
+        public string ProtoPropertyName { get; set; }
         public string Type { get; set; }
         public string FullyQualifiedType { get; set; }
         public string ProtoType { get; set; }
@@ -51,6 +56,7 @@ namespace Svrnty.CQRS.Grpc.Generators.Models
         public PropertyInfo()
         {
             Name = string.Empty;
+            ProtoPropertyName = string.Empty;
             Type = string.Empty;
             FullyQualifiedType = string.Empty;
             ProtoType = string.Empty;

Svrnty.CQRS.Grpc.Generators/Models/QueryInfo.cs

@@ -13,6 +13,26 @@ namespace Svrnty.CQRS.Grpc.Generators.Models
         public string HandlerInterfaceName { get; set; }
         public List<PropertyInfo> ResultProperties { get; set; }
         public bool IsResultPrimitiveType { get; set; }
+        /// <summary>
+        /// True if the result type is a collection (List, IEnumerable, etc.)
+        /// </summary>
+        public bool IsResultCollection { get; set; }
+        /// <summary>
+        /// The element type name if IsResultCollection is true
+        /// </summary>
+        public string ResultElementType { get; set; }
+        /// <summary>
+        /// The fully qualified element type name if IsResultCollection is true
+        /// </summary>
+        public string ResultElementTypeFullyQualified { get; set; }
+        /// <summary>
+        /// True if the result type is nullable (ends with ? or is Nullable<T>)
+        /// </summary>
+        public bool IsResultNullable { get; set; }
+        /// <summary>
+        /// The result type name without the nullable annotation (e.g., "CnfFoodDetailItem" instead of "CnfFoodDetailItem?")
+        /// </summary>
+        public string ResultTypeWithoutNullable { get; set; }
 
         public QueryInfo()
         {
@@ -25,6 +45,11 @@ namespace Svrnty.CQRS.Grpc.Generators.Models
             HandlerInterfaceName = string.Empty;
             ResultProperties = new List<PropertyInfo>();
             IsResultPrimitiveType = false;
+            IsResultCollection = false;
+            ResultElementType = string.Empty;
+            ResultElementTypeFullyQualified = string.Empty;
+            IsResultNullable = false;
+            ResultTypeWithoutNullable = string.Empty;
         }
     }
 }

Svrnty.CQRS.Grpc.Generators/ProtoFileGenerator.cs

@@ -403,9 +403,14 @@ internal class ProtoFileGenerator
         _messagesBuilder.AppendLine();
 
         // Generate complex type message after closing the response message
-        if (resultType != null && IsComplexType(resultType))
+        // Use GetElementOrUnderlyingType to extract element type from collections (e.g., List<CnfFoodItem> -> CnfFoodItem)
+        if (resultType != null)
         {
-            GenerateComplexTypeMessage(resultType as INamedTypeSymbol);
+            var underlyingType = ProtoFileTypeMapper.GetElementOrUnderlyingType(resultType);
+            if (IsComplexType(underlyingType) && underlyingType is INamedTypeSymbol namedType)
+            {
+                GenerateComplexTypeMessage(namedType);
+            }
         }
     }
 

Svrnty.CQRS.Grpc.Generators/build/Svrnty.CQRS.Grpc.Generators.props

@@ -2,5 +2,15 @@
   <PropertyGroup>
     <!-- Marker to indicate Svrnty.CQRS.Grpc.Generators is referenced -->
     <SvrntyCqrsGrpcGeneratorsVersion>$(SvrntyCqrsGrpcGeneratorsVersion)</SvrntyCqrsGrpcGeneratorsVersion>
+
+    <!-- Path resolution for both NuGet package and project reference -->
+    <_SvrntyCqrsGrpcGeneratorsPath Condition="Exists('$(MSBuildThisFileDirectory)..\analyzers\dotnet\cs\Svrnty.CQRS.Grpc.Generators.dll')">$(MSBuildThisFileDirectory)..\analyzers\dotnet\cs\Svrnty.CQRS.Grpc.Generators.dll</_SvrntyCqrsGrpcGeneratorsPath>
+    <_SvrntyCqrsGrpcGeneratorsPath Condition="'$(_SvrntyCqrsGrpcGeneratorsPath)' == '' AND Exists('$(MSBuildThisFileDirectory)..\bin\Debug\netstandard2.0\Svrnty.CQRS.Grpc.Generators.dll')">$(MSBuildThisFileDirectory)..\bin\Debug\netstandard2.0\Svrnty.CQRS.Grpc.Generators.dll</_SvrntyCqrsGrpcGeneratorsPath>
+    <_SvrntyCqrsGrpcGeneratorsPath Condition="'$(_SvrntyCqrsGrpcGeneratorsPath)' == '' AND Exists('$(MSBuildThisFileDirectory)..\bin\Release\netstandard2.0\Svrnty.CQRS.Grpc.Generators.dll')">$(MSBuildThisFileDirectory)..\bin\Release\netstandard2.0\Svrnty.CQRS.Grpc.Generators.dll</_SvrntyCqrsGrpcGeneratorsPath>
   </PropertyGroup>
+
+  <!-- Explicitly add the generator to the Analyzer ItemGroup -->
+  <ItemGroup Condition="'$(_SvrntyCqrsGrpcGeneratorsPath)' != ''">
+    <Analyzer Include="$(_SvrntyCqrsGrpcGeneratorsPath)" />
+  </ItemGroup>
 </Project>