diff --git a/protographic/SDL_PROTO_RULES.md b/protographic/SDL_PROTO_RULES.md
index b7c1da192c..814552f057 100644
--- a/protographic/SDL_PROTO_RULES.md
+++ b/protographic/SDL_PROTO_RULES.md
@@ -230,29 +230,116 @@ enum UserRole {
 }
 ```
 
-## Nested List Types
+## List Types
 
-For nested lists in GraphQL (e.g., `[[Type]]`), Protographic creates a wrapper message:
+Protographic handles GraphQL list nullability by creating wrapper messages when needed, since Protocol Buffers doesn't natively support nullable lists or nested list structures.
+
+### Core Concepts
+
+- **Non-nullable single-level lists**: Use the `repeated` keyword directly
+- **Nullable lists**: Wrapped in `ListOf{Type}` messages 
+- **Nested lists**: Always use wrapper messages with multiple `ListOf` prefixes based on nesting level (e.g., `ListOfListOfString`)
+- **Nullable list items**: Currently ignored (no wrapper generated for item nullability)
+
+### Non-Nullable Single Lists
+Non-nullable lists use `repeated` fields directly:
+
+```graphql
+type User {
+  tags: [String!]!
+}
+```
+
+Maps to:
+
+```protobuf
+message User {
+  repeated string tags = 1;
+}
+```
+
+### Nullable Single Lists
+
+Nullable lists require wrapper messages:
 
 ```graphql
-type Matrix {
-  values: [[Int!]!]!
+type User {
+  optionalTags: [String]
 }
 ```
 
 Maps to:
 
 ```protobuf
-message IntList {
-  repeated int32 result = 1;
+message ListOfString {
+  repeated string items = 1;
 }
 
-message Matrix {
-  repeated IntList values = 1;
+message User {
+  ListOfString optional_tags = 1;
 }
 ```
 
-This approach is used for any nested list, regardless of the depth of nesting. For complex nested types, wrapper messages are created automatically with the naming convention of `{BaseType}List`.
+### Non-Nullable Nested Lists
+
+Non-nullable nested lists always use wrapper messages to preserve inner list nullability:
+
+```graphql
+type User {
+  categories: [[String!]!]!
+}
+```
+
+Maps to:
+
+```protobuf
+message ListOfString {
+  repeated string items = 1;
+}
+
+message ListOfListOfString {
+  message List {
+    repeated ListOfString items = 1;
+  }
+  List list = 1;
+}
+
+message User {
+  ListOfListOfString categories = 1;
+}
+```
+
+### Nullable Nested Lists
+
+Nullable nested lists use nested wrapper messages:
+
+```graphql
+type User {
+  posts: [[String]]
+}
+```
+
+Maps to:
+
+```protobuf
+message ListOfString {
+  repeated string items = 1;
+}
+
+message ListOfListOfString {
+  message List {
+    repeated ListOfString items = 1;
+  }
+  List list = 1;
+}
+
+message User {
+  ListOfListOfString posts = 1;
+}
+```
+
+
+
 
 ## Field Numbering and Stability
 
diff --git a/protographic/src/sdl-to-proto-visitor.ts b/protographic/src/sdl-to-proto-visitor.ts
index 91a4507f58..eea6c39e8b 100644
--- a/protographic/src/sdl-to-proto-visitor.ts
+++ b/protographic/src/sdl-to-proto-visitor.ts
@@ -6,7 +6,10 @@ import {
   GraphQLField,
   GraphQLInputObjectType,
   GraphQLInterfaceType,
+  GraphQLList,
   GraphQLNamedType,
+  GraphQLNonNull,
+  GraphQLNullableType,
   GraphQLObjectType,
   GraphQLSchema,
   GraphQLType,
@@ -84,6 +87,14 @@ export interface GraphQLToProtoTextVisitorOptions {
   includeComments?: boolean;
 }
 
+/**
+ * Data structure for formatting message fields
+ */
+interface ProtoType {
+  typeName: string;
+  isRepeated: boolean;
+}
+
 /**
  * Visitor that converts GraphQL SDL to Protocol Buffer text definition
  *
@@ -882,11 +893,10 @@ Example:
         }
 
         // Check if the argument is a list type and add the repeated keyword if needed
-        const isRepeated = isListType(arg.type) || (isNonNullType(arg.type) && isListType(arg.type.ofType));
-        if (isRepeated) {
-          messageLines.push(`  repeated ${argType} ${argProtoName} = ${fieldNumber};`);
+        if (argType.isRepeated) {
+          messageLines.push(`  repeated ${argType.typeName} ${argProtoName} = ${fieldNumber};`);
         } else {
-          messageLines.push(`  ${argType} ${argProtoName} = ${fieldNumber};`);
+          messageLines.push(`  ${argType.typeName} ${argProtoName} = ${fieldNumber};`);
         }
 
         // Add complex input types to the queue for processing
@@ -940,8 +950,6 @@ Example:
     }
 
     const returnType = this.getProtoTypeFromGraphQL(field.type);
-    const isRepeated = isListType(field.type) || (isNonNullType(field.type) && isListType(field.type.ofType));
-
     // Get the appropriate field number, respecting the lock
     const fieldNumber = this.getFieldNumber(responseName, protoFieldName, 1);
 
@@ -951,10 +959,10 @@ Example:
       messageLines.push(...this.formatComment(field.description, 1));
     }
 
-    if (isRepeated) {
-      messageLines.push(`  repeated ${returnType} ${protoFieldName} = ${fieldNumber};`);
+    if (returnType.isRepeated) {
+      messageLines.push(`  repeated ${returnType.typeName} ${protoFieldName} = ${fieldNumber};`);
     } else {
-      messageLines.push(`  ${returnType} ${protoFieldName} = ${fieldNumber};`);
+      messageLines.push(`  ${returnType.typeName} ${protoFieldName} = ${fieldNumber};`);
     }
 
     messageLines.push('}');
@@ -1105,7 +1113,6 @@ Example:
 
       const field = fields[fieldName];
       const fieldType = this.getProtoTypeFromGraphQL(field.type);
-      const isRepeated = isListType(field.type) || (isNonNullType(field.type) && isListType(field.type.ofType));
       const protoFieldName = graphqlFieldToProtoField(fieldName);
 
       // Get the appropriate field number, respecting the lock
@@ -1116,10 +1123,10 @@ Example:
         this.protoText.push(...this.formatComment(field.description, 1)); // Field comment, indent 1 level
       }
 
-      if (isRepeated) {
-        this.protoText.push(`  repeated ${fieldType} ${protoFieldName} = ${fieldNumber};`);
+      if (fieldType.isRepeated) {
+        this.protoText.push(`  repeated ${fieldType.typeName} ${protoFieldName} = ${fieldNumber};`);
       } else {
-        this.protoText.push(`  ${fieldType} ${protoFieldName} = ${fieldNumber};`);
+        this.protoText.push(`  ${fieldType.typeName} ${protoFieldName} = ${fieldNumber};`);
       }
 
       // Queue complex field types for processing
@@ -1177,7 +1184,6 @@ Example:
 
       const field = fields[fieldName];
       const fieldType = this.getProtoTypeFromGraphQL(field.type);
-      const isRepeated = isListType(field.type) || (isNonNullType(field.type) && isListType(field.type.ofType));
       const protoFieldName = graphqlFieldToProtoField(fieldName);
 
       // Get the appropriate field number, respecting the lock
@@ -1188,10 +1194,10 @@ Example:
         this.protoText.push(...this.formatComment(field.description, 1)); // Field comment, indent 1 level
       }
 
-      if (isRepeated) {
-        this.protoText.push(`  repeated ${fieldType} ${protoFieldName} = ${fieldNumber};`);
+      if (fieldType.isRepeated) {
+        this.protoText.push(`  repeated ${fieldType.typeName} ${protoFieldName} = ${fieldNumber};`);
       } else {
-        this.protoText.push(`  ${fieldType} ${protoFieldName} = ${fieldNumber};`);
+        this.protoText.push(`  ${fieldType.typeName} ${protoFieldName} = ${fieldNumber};`);
       }
 
       // Queue complex field types for processing
@@ -1413,117 +1419,201 @@ Example:
    * @param ignoreWrapperTypes - If true, do not use wrapper types for nullable scalar fields
    * @returns The corresponding Protocol Buffer type name
    */
-  private getProtoTypeFromGraphQL(graphqlType: GraphQLType, ignoreWrapperTypes: boolean = false): string {
+  private getProtoTypeFromGraphQL(graphqlType: GraphQLType, ignoreWrapperTypes: boolean = false): ProtoType {
+    // Nullable lists need to be handled first, otherwise they will be treated as scalar types
+    if (isListType(graphqlType) || (isNonNullType(graphqlType) && isListType(graphqlType.ofType))) {
+      return this.handleListType(graphqlType);
+    }
     // For nullable scalar types, use wrapper types
     if (isScalarType(graphqlType)) {
       if (ignoreWrapperTypes) {
-        return SCALAR_TYPE_MAP[graphqlType.name] || 'string';
+        return { typeName: SCALAR_TYPE_MAP[graphqlType.name] || 'string', isRepeated: false };
       }
       this.usesWrapperTypes = true; // Track that we're using wrapper types
-      return SCALAR_WRAPPER_TYPE_MAP[graphqlType.name] || 'google.protobuf.StringValue';
+      return {
+        typeName: SCALAR_WRAPPER_TYPE_MAP[graphqlType.name] || 'google.protobuf.StringValue',
+        isRepeated: false,
+      };
     }
 
     if (isEnumType(graphqlType)) {
-      return graphqlType.name;
+      return { typeName: graphqlType.name, isRepeated: false };
     }
 
     if (isNonNullType(graphqlType)) {
       // For non-null scalar types, use the base type
       if (isScalarType(graphqlType.ofType)) {
-        return SCALAR_TYPE_MAP[graphqlType.ofType.name] || 'string';
+        return { typeName: SCALAR_TYPE_MAP[graphqlType.ofType.name] || 'string', isRepeated: false };
       }
 
       return this.getProtoTypeFromGraphQL(graphqlType.ofType);
     }
+    // Named types (object, interface, union, input)
+    const namedType = graphqlType as GraphQLNamedType;
+    if (namedType && typeof namedType.name === 'string') {
+      return { typeName: namedType.name, isRepeated: false };
+    }
 
-    if (isListType(graphqlType)) {
-      // Handle nested list types (e.g., [[Type]])
-      const innerType = graphqlType.ofType;
+    return { typeName: 'string', isRepeated: false }; // Default fallback
+  }
 
-      // If the inner type is also a list, we need to use a wrapper message
-      if (isListType(innerType) || (isNonNullType(innerType) && isListType(innerType.ofType))) {
-        // Find the most inner type by unwrapping all lists and non-nulls
-        let currentType: GraphQLType = innerType;
-        while (isListType(currentType) || isNonNullType(currentType)) {
-          currentType = isListType(currentType) ? currentType.ofType : (currentType as any).ofType;
-        }
+  /**
+   * Converts GraphQL list types to appropriate Protocol Buffer representations.
+   *
+   * For non-nullable, single-level lists (e.g., [String!]!), generates simple repeated fields.
+   * For nullable lists (e.g., [String]) or nested lists (e.g., [[String]]), creates wrapper
+   * messages to properly handle nullability in proto3.
+   *
+   * Examples:
+   * - [String!]! → repeated string field_name = 1;
+   * - [String] → ListOfString field_name = 1; (with wrapper message)
+   * - [[String!]!]! → ListOfListOfString field_name = 1; (with nested wrapper messages)
+   * - [[String]] → ListOfListOfString field_name = 1; (with nested wrapper messages)
+   *
+   * @param graphqlType - The GraphQL list type to convert
+   * @returns ProtoType object containing the type name and whether it should be repeated
+   */
+  private handleListType(graphqlType: GraphQLList<GraphQLType> | GraphQLNonNull<GraphQLList<GraphQLType>>): ProtoType {
+    const listType = this.unwrapNonNullType(graphqlType);
+    const isNullableList = !isNonNullType(graphqlType);
+    const isNestedList = this.isNestedListType(listType);
 
-        // Get the name of the inner type and create wrapper name
-        const namedInnerType = currentType as GraphQLNamedType;
-        const wrapperName = `${namedInnerType.name}List`;
+    // Simple non-nullable lists can use repeated fields directly
+    if (!isNullableList && !isNestedList) {
+      return { ...this.getProtoTypeFromGraphQL(getNamedType(listType), true), isRepeated: true };
+    }
 
-        // Generate the wrapper message if not already created
-        if (!this.processedTypes.has(wrapperName) && !this.nestedListWrappers.has(wrapperName)) {
-          this.createNestedListWrapper(wrapperName, namedInnerType);
-        }
+    // Nullable or nested lists need wrapper messages
+    const baseType = getNamedType(listType);
+    const nestingLevel = this.calculateNestingLevel(listType);
 
-        return wrapperName;
-      }
+    // For nested lists, always use full nesting level to preserve inner list nullability
+    // For single-level nullable lists, use nesting level 1
+    const wrapperNestingLevel = isNestedList ? nestingLevel : 1;
 
-      return this.getProtoTypeFromGraphQL(innerType, true);
+    // Generate all required wrapper messages
+    let wrapperName = '';
+    for (let i = 1; i <= wrapperNestingLevel; i++) {
+      wrapperName = this.createNestedListWrapper(i, baseType);
     }
 
-    // Named types (object, interface, union, input)
-    const namedType = graphqlType as GraphQLNamedType;
-    if (namedType && typeof namedType.name === 'string') {
-      return namedType.name;
+    // For nested lists, never use repeated at field level to preserve nullability
+    return { typeName: wrapperName, isRepeated: false };
+  }
+
+  /**
+   * Unwraps a GraphQL type from a GraphQLNonNull type
+   */
+  private unwrapNonNullType<T extends GraphQLType>(graphqlType: T | GraphQLNonNull<T>): T {
+    return isNonNullType(graphqlType) ? (graphqlType.ofType as T) : graphqlType;
+  }
+
+  /**
+   * Checks if a GraphQL list type contains nested lists
+   * Type guard that narrows the input type when nested lists are detected
+   */
+  private isNestedListType(
+    listType: GraphQLList<GraphQLType>,
+  ): listType is GraphQLList<GraphQLList<GraphQLType> | GraphQLNonNull<GraphQLList<GraphQLType>>> {
+    return isListType(listType.ofType) || (isNonNullType(listType.ofType) && isListType(listType.ofType.ofType));
+  }
+
+  /**
+   * Calculates the nesting level of a GraphQL list type
+   */
+  private calculateNestingLevel(listType: GraphQLList<GraphQLType>): number {
+    let level = 1;
+    let currentType: GraphQLType = listType.ofType;
+
+    while (true) {
+      if (isNonNullType(currentType)) {
+        currentType = currentType.ofType;
+      } else if (isListType(currentType)) {
+        currentType = currentType.ofType;
+        level++;
+      } else {
+        break;
+      }
     }
 
-    return 'string'; // Default fallback
+    return level;
   }
 
   /**
-   * Create a nested list wrapper message for the given base type
+   * Creates wrapper messages for nullable or nested GraphQL lists.
+   *
+   * Generates Protocol Buffer message definitions to handle list nullability and nesting.
+   * The wrapper messages are stored and later included in the final proto output.
+   *
+   * For level 1: Creates simple wrapper like:
+   *   message ListOfString {
+   *     repeated string items = 1;
+   *   }
+   *
+   * For level > 1: Creates nested wrapper structures like:
+   *   message ListOfListOfString {
+   *     message List {
+   *       repeated ListOfString items = 1;
+   *     }
+   *     List list = 1;
+   *   }
+   *
+   * @param level - The nesting level (1 for simple wrapper, >1 for nested structures)
+   * @param baseType - The GraphQL base type being wrapped (e.g., String, User, etc.)
+   * @returns The generated wrapper message name (e.g., "ListOfString", "ListOfListOfUser")
    */
-  private createNestedListWrapper(wrapperName: string, baseType: GraphQLNamedType): void {
-    // Skip if already processed
+  private createNestedListWrapper(level: number, baseType: GraphQLNamedType): string {
+    const wrapperName = `${'ListOf'.repeat(level)}${baseType.name}`;
+
+    // Return existing wrapper if already created
     if (this.processedTypes.has(wrapperName) || this.nestedListWrappers.has(wrapperName)) {
-      return;
+      return wrapperName;
     }
 
-    // Mark as processed to avoid recursion
     this.processedTypes.add(wrapperName);
 
-    // Check for field removals if lock data exists for this wrapper
-    const lockData = this.lockManager.getLockData();
-    if (lockData.messages[wrapperName]) {
-      const originalFieldNames = Object.keys(lockData.messages[wrapperName].fields);
-      const currentFieldNames = ['result'];
-      this.trackRemovedFields(wrapperName, originalFieldNames, currentFieldNames);
-    }
-
-    // Create a temporary array for the wrapper definition
-    const messageLines: string[] = [];
+    const messageLines = this.buildWrapperMessage(wrapperName, level, baseType);
+    this.nestedListWrappers.set(wrapperName, messageLines.join('\n'));
 
-    // Add a description comment for the wrapper message
-    if (this.includeComments) {
-      const wrapperComment = `Wrapper message for a list of ${baseType.name}.`;
-      messageLines.push(...this.formatComment(wrapperComment, 0)); // Top-level comment, no indent
-    }
+    return wrapperName;
+  }
 
-    messageLines.push(`message ${wrapperName} {`);
+  /**
+   * Builds the message lines for a wrapper message
+   */
+  private buildWrapperMessage(wrapperName: string, level: number, baseType: GraphQLNamedType): string[] {
+    const lines: string[] = [];
 
-    // Add reserved field numbers if any exist
-    const messageLock = lockData.messages[wrapperName];
-    if (messageLock?.reservedNumbers && messageLock.reservedNumbers.length > 0) {
-      messageLines.push(`  reserved ${this.formatReservedNumbers(messageLock.reservedNumbers)};`);
+    // Add comment if enabled
+    if (this.includeComments) {
+      lines.push(...this.formatComment(`Wrapper message for a list of ${baseType.name}.`, 0));
     }
 
-    // Get the appropriate field number from the lock
-    const fieldNumber = this.getFieldNumber(wrapperName, 'result', 1);
+    lines.push(`message ${wrapperName} {`);
 
-    // For the inner type, we need to get the proto type for the base type
-    const protoType = this.getProtoTypeFromGraphQL(baseType, true);
-    messageLines.push(`  repeated ${protoType} result = ${fieldNumber};`);
+    const formatIndent = (indent: number, content: string) => {
+      return '  '.repeat(indent) + content;
+    };
 
-    messageLines.push('}');
-    messageLines.push('');
+    if (level > 1) {
+      // Nested structure for deep lists
+      const innerWrapperName = `${'ListOf'.repeat(level - 1)}${baseType.name}`;
+      lines.push(
+        formatIndent(1, `message List {`),
+        formatIndent(2, `repeated ${innerWrapperName} items = 1;`),
+        formatIndent(1, `}`),
+      );
 
-    // Ensure the wrapper message is registered in the lock manager data
-    this.lockManager.reconcileMessageFieldOrder(wrapperName, ['result']);
+      // Wrapper types always use deterministic field numbers - 'list' field is always 1
+      lines.push(formatIndent(1, `List list = 1;`));
+    } else {
+      // Simple repeated field for level 1 - 'items' field is always 1
+      const protoType = this.getProtoTypeFromGraphQL(baseType, true);
+      lines.push(formatIndent(1, `repeated ${protoType.typeName} items = 1;`));
+    }
 
-    // Store the wrapper message for later inclusion in the output
-    this.nestedListWrappers.set(wrapperName, messageLines.join('\n'));
+    lines.push('}', '');
+    return lines;
   }
 
   /**
diff --git a/protographic/tests/sdl-to-proto/01-basic-types.test.ts b/protographic/tests/sdl-to-proto/01-basic-types.test.ts
index c77a85a517..539b9da252 100644
--- a/protographic/tests/sdl-to-proto/01-basic-types.test.ts
+++ b/protographic/tests/sdl-to-proto/01-basic-types.test.ts
@@ -140,12 +140,17 @@ describe('SDL to Proto - Basic Types', () => {
         rpc QueryStringList(QueryStringListRequest) returns (QueryStringListResponse) {}
       }
 
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
       // Request message for stringList operation.
       message QueryStringListRequest {
       }
       // Response message for stringList operation.
       message QueryStringListResponse {
-        repeated string string_list = 1;
+        ListOfString string_list = 1;
       }
       // Request message for intList operation.
       message QueryIntListRequest {
@@ -240,6 +245,11 @@ describe('SDL to Proto - Basic Types', () => {
         rpc QueryUser(QueryUserRequest) returns (QueryUserResponse) {}
       }
 
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
       // Request message for user operation.
       message QueryUserRequest {
         string id = 1;
@@ -256,7 +266,7 @@ describe('SDL to Proto - Basic Types', () => {
       }
       // Response message for filteredUsers operation.
       message QueryFilteredUsersResponse {
-        repeated User filtered_users = 1;
+        ListOfUser filtered_users = 1;
       }
 
       message User {
@@ -371,7 +381,7 @@ describe('SDL to Proto - Basic Types', () => {
       
       type Query {
         categoriesByKinds(kinds: [CategoryKind!]!): [Category!]!
-        filterItems(ids: [ID!], tags: [String]): [String]
+        filterItems(ids: [ID!]!, tags: [String]!): [String!]!
       }
     `;
 
@@ -467,18 +477,47 @@ describe('SDL to Proto - Basic Types', () => {
       }
 
       // Wrapper message for a list of Float.
-      message FloatList {
-        repeated double result = 1;
+      message ListOfFloat {
+        repeated double items = 1;
+      }
+
+      // Wrapper message for a list of Int.
+      message ListOfInt {
+        repeated int32 items = 1;
+      }
+
+      // Wrapper message for a list of Float.
+      message ListOfListOfFloat {
+        message List {
+          repeated ListOfFloat items = 1;
+        }
+        List list = 1;
       }
 
       // Wrapper message for a list of Int.
-      message IntList {
-        repeated int32 result = 1;
+      message ListOfListOfInt {
+        message List {
+          repeated ListOfInt items = 1;
+        }
+        List list = 1;
       }
 
       // Wrapper message for a list of Point.
-      message PointList {
-        repeated Point result = 1;
+      message ListOfListOfPoint {
+        message List {
+          repeated ListOfPoint items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Point.
+      message ListOfPoint {
+        repeated Point items = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
       }
 
       // Request message for getMatrix operation.
@@ -490,23 +529,23 @@ describe('SDL to Proto - Basic Types', () => {
       }
       // Request message for processMatrix operation.
       message QueryProcessMatrixRequest {
-        repeated FloatList matrix = 1;
+        ListOfListOfFloat matrix = 1;
       }
       // Response message for processMatrix operation.
       message QueryProcessMatrixResponse {
-        repeated IntList process_matrix = 1;
+        ListOfListOfInt process_matrix = 1;
       }
       // Request message for transformData operation.
       message QueryTransformDataRequest {
-        repeated PointList points = 1;
+        ListOfListOfPoint points = 1;
       }
       // Response message for transformData operation.
       message QueryTransformDataResponse {
-        repeated string transform_data = 1;
+        ListOfString transform_data = 1;
       }
 
       message Matrix {
-        repeated IntList values = 1;
+        ListOfListOfInt values = 1;
         repeated string labels = 2;
       }
 
@@ -662,6 +701,16 @@ describe('SDL to Proto - Basic Types', () => {
         rpc QueryUser(QueryUserRequest) returns (QueryUserResponse) {}
       }
 
+      // Wrapper message for a list of TreeNode.
+      message ListOfTreeNode {
+        repeated TreeNode items = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
       // Request message for user operation.
       message QueryUserRequest {
         string id = 1;
@@ -702,7 +751,7 @@ describe('SDL to Proto - Basic Types', () => {
         string name = 2;
         google.protobuf.StringValue email = 3;
         UserProfile profile = 4;
-        repeated User friends = 5;
+        ListOfUser friends = 5;
       }
 
       message TreeNode {
@@ -710,7 +759,7 @@ describe('SDL to Proto - Basic Types', () => {
         google.protobuf.StringValue value = 2;
         google.protobuf.DoubleValue weight = 3;
         bool is_leaf = 4;
-        repeated TreeNode children = 5;
+        ListOfTreeNode children = 5;
         TreeNode parent = 6;
       }
 
diff --git a/protographic/tests/sdl-to-proto/02-complex-types.test.ts b/protographic/tests/sdl-to-proto/02-complex-types.test.ts
index 58a80ccaa0..d95bd26fa6 100644
--- a/protographic/tests/sdl-to-proto/02-complex-types.test.ts
+++ b/protographic/tests/sdl-to-proto/02-complex-types.test.ts
@@ -36,13 +36,18 @@ describe('SDL to Proto - Complex Types', () => {
         rpc QueryUsersByRole(QueryUsersByRoleRequest) returns (QueryUsersByRoleResponse) {}
       }
 
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
       // Request message for usersByRole operation.
       message QueryUsersByRoleRequest {
         UserRole role = 1;
       }
       // Response message for usersByRole operation.
       message QueryUsersByRoleResponse {
-        repeated User users_by_role = 1;
+        ListOfUser users_by_role = 1;
       }
 
       message User {
@@ -224,6 +229,11 @@ describe('SDL to Proto - Complex Types', () => {
         rpc QueryRootNode(QueryRootNodeRequest) returns (QueryRootNodeResponse) {}
       }
 
+      // Wrapper message for a list of TreeNode.
+      message ListOfTreeNode {
+        repeated TreeNode items = 1;
+      }
+
       // Request message for rootNode operation.
       message QueryRootNodeRequest {
       }
@@ -244,7 +254,7 @@ describe('SDL to Proto - Complex Types', () => {
         string id = 1;
         string value = 2;
         TreeNode parent = 3;
-        repeated TreeNode children = 4;
+        ListOfTreeNode children = 4;
       }"
     `);
   });
@@ -293,20 +303,30 @@ describe('SDL to Proto - Complex Types', () => {
         rpc QueryUsers(QueryUsersRequest) returns (QueryUsersResponse) {}
       }
 
+      // Wrapper message for a list of AddressInput.
+      message ListOfAddressInput {
+        repeated AddressInput items = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
       // Request message for users operation.
       message QueryUsersRequest {
         UserFilterInput filter = 1;
       }
       // Response message for users operation.
       message QueryUsersResponse {
-        repeated User users = 1;
+        ListOfUser users = 1;
       }
 
       message UserFilterInput {
         google.protobuf.StringValue name_contains = 1;
         google.protobuf.Int32Value min_age = 2;
         google.protobuf.Int32Value max_age = 3;
-        repeated AddressInput addresses = 4;
+        ListOfAddressInput addresses = 4;
       }
 
       message User {
diff --git a/protographic/tests/sdl-to-proto/05-edge-cases.test.ts b/protographic/tests/sdl-to-proto/05-edge-cases.test.ts
index de21cd0c2d..3b9b1a9b6c 100644
--- a/protographic/tests/sdl-to-proto/05-edge-cases.test.ts
+++ b/protographic/tests/sdl-to-proto/05-edge-cases.test.ts
@@ -364,6 +364,21 @@ describe('SDL to Proto - Edge Cases and Error Handling', () => {
         rpc QueryUsers(QueryUsersRequest) returns (QueryUsersResponse) {}
       }
 
+      // Wrapper message for a list of Comment.
+      message ListOfComment {
+        repeated Comment items = 1;
+      }
+
+      // Wrapper message for a list of Post.
+      message ListOfPost {
+        repeated Post items = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
       // Key message for User entity lookup
       message LookupUserByIdRequestKey {
         // Key field for User entity lookup.
@@ -552,7 +567,7 @@ describe('SDL to Proto - Edge Cases and Error Handling', () => {
         string created_at = 4;
         google.protobuf.StringValue metadata = 5;
         UserStatus status = 6;
-        repeated Post posts = 7;
+        ListOfPost posts = 7;
         UserProfile profile = 8;
       }
 
@@ -561,11 +576,11 @@ describe('SDL to Proto - Edge Cases and Error Handling', () => {
         string title = 2;
         string content = 3;
         User author = 4;
-        repeated string tags = 5;
+        ListOfString tags = 5;
         string created_at = 6;
         google.protobuf.StringValue updated_at = 7;
         PostStatus status = 8;
-        repeated Comment comments = 9;
+        ListOfComment comments = 9;
       }
 
       message Comment {
@@ -581,7 +596,7 @@ describe('SDL to Proto - Edge Cases and Error Handling', () => {
         string query = 1;
         google.protobuf.Int32Value limit = 2;
         google.protobuf.Int32Value offset = 3;
-        repeated string types = 4;
+        ListOfString types = 4;
       }
 
       message SearchResult {
@@ -608,7 +623,7 @@ describe('SDL to Proto - Edge Cases and Error Handling', () => {
       message PostInput {
         string title = 1;
         string content = 2;
-        repeated string tags = 3;
+        ListOfString tags = 3;
         PostStatus status = 4;
       }
 
diff --git a/protographic/tests/sdl-to-proto/06-field-ordering.test.ts b/protographic/tests/sdl-to-proto/06-field-ordering.test.ts
index e70fea24f4..be876dc6f2 100644
--- a/protographic/tests/sdl-to-proto/06-field-ordering.test.ts
+++ b/protographic/tests/sdl-to-proto/06-field-ordering.test.ts
@@ -10,6 +10,7 @@ import {
   getServiceMethods,
   getReservedNumbers,
 } from '../util';
+import { isNull } from 'lodash-es';
 
 describe('Field Ordering and Preservation', () => {
   describe('Basic Message Field Ordering', () => {
@@ -1123,4 +1124,320 @@ describe('Field Ordering and Preservation', () => {
       expect(priceRangeFields2['currency']).toBe(currencyNumber);
     });
   });
+
+  describe('List Wrapper Types Field Ordering', () => {
+    test('should preserve field numbers for simple list wrapper types', () => {
+      // Initial schema with nullable lists that generate simple wrapper types
+      const initialSchema = buildSchema(`
+        type User {
+          id: ID!
+          name: String!
+          tags: [String]        # nullable list -> generates ListOfString wrapper
+          scores: [Int]         # nullable list -> generates ListOfInt wrapper
+          categories: [User]    # nullable list -> generates ListOfUser wrapper
+        }
+        
+        type Query {
+          getUsers: [User]
+        }
+      `);
+
+      // Create the visitor with no initial lock data
+      const visitor1 = new GraphQLToProtoTextVisitor(initialSchema, {
+        serviceName: 'UserService',
+      });
+
+      // Generate the first proto
+      const proto1 = visitor1.visit();
+
+      // Parse the proto with protobufjs
+      const root1 = loadProtoFromText(proto1);
+
+      // Verify wrapper types exist and get their field numbers
+      const listOfStringFields = getFieldNumbersFromMessage(root1, 'ListOfString');
+      const listOfIntFields = getFieldNumbersFromMessage(root1, 'ListOfInt');
+      const listOfUserFields = getFieldNumbersFromMessage(root1, 'ListOfUser');
+
+      // Store original field numbers for wrapper types
+      const stringItemsNumber = listOfStringFields['items'];
+      const intItemsNumber = listOfIntFields['items'];
+      const userItemsNumber = listOfUserFields['items'];
+
+      // Verify all wrapper types have the 'items' field with field number 1
+      expect(stringItemsNumber).toBe(1);
+      expect(intItemsNumber).toBe(1);
+      expect(userItemsNumber).toBe(1);
+
+      // Get the generated lock data
+      const lockData = visitor1.getGeneratedLockData();
+      expect(lockData).not.toBeNull();
+
+      // Verify wrapper types are NOT in lock data (they're auto-generated with deterministic field numbers)
+      expect(lockData!.messages['ListOfString']).toBeUndefined();
+      expect(lockData!.messages['ListOfInt']).toBeUndefined();
+      expect(lockData!.messages['ListOfUser']).toBeUndefined();
+
+      // Modified schema with additional nullable lists (triggers regeneration)
+      const modifiedSchema = buildSchema(`
+        type User {
+          id: ID!
+          name: String!
+          tags: [String]        # existing nullable list
+          scores: [Int]         # existing nullable list  
+          categories: [User]    # existing nullable list
+          ratings: [Float]      # new nullable list -> generates ListOfFloat wrapper
+        }
+        
+        type Query {
+          getUsers: [User]
+        }
+      `);
+
+      // Create another visitor using the generated lock data
+      const visitor2 = new GraphQLToProtoTextVisitor(modifiedSchema, {
+        serviceName: 'UserService',
+        lockData: lockData || undefined,
+      });
+
+      // Generate the second proto
+      const proto2 = visitor2.visit();
+
+      // Parse the proto with protobufjs
+      const root2 = loadProtoFromText(proto2);
+
+      // Verify existing wrapper types preserved their field numbers
+      const listOfStringFields2 = getFieldNumbersFromMessage(root2, 'ListOfString');
+      const listOfIntFields2 = getFieldNumbersFromMessage(root2, 'ListOfInt');
+      const listOfUserFields2 = getFieldNumbersFromMessage(root2, 'ListOfUser');
+      const listOfFloatFields2 = getFieldNumbersFromMessage(root2, 'ListOfFloat');
+
+      // Verify field numbers are preserved
+      expect(listOfStringFields2['items']).toBe(stringItemsNumber);
+      expect(listOfIntFields2['items']).toBe(intItemsNumber);
+      expect(listOfUserFields2['items']).toBe(userItemsNumber);
+
+      // Verify new wrapper type has field number 1
+      expect(listOfFloatFields2['items']).toBe(1);
+    });
+
+    test('should preserve field numbers for nested list wrapper types', () => {
+      // Initial schema with nested lists that generate nested wrapper types
+      const initialSchema = buildSchema(`
+        type User {
+          id: ID!
+          name: String!
+          tagGroups: [[String]]      # nested nullable list -> generates ListOfListOfString wrapper
+          scoreMatrix: [[Int]]       # nested nullable list -> generates ListOfListOfInt wrapper
+        }
+        
+        type Query {
+          getUsers: [User]
+        }
+      `);
+
+      // Create the visitor with no initial lock data
+      const visitor1 = new GraphQLToProtoTextVisitor(initialSchema, {
+        serviceName: 'UserService',
+      });
+
+      // Generate the first proto
+      const proto1 = visitor1.visit();
+
+      // Parse the proto with protobufjs
+      const root1 = loadProtoFromText(proto1);
+
+      // Verify nested wrapper types exist and get their field numbers
+      const listOfListOfStringFields = getFieldNumbersFromMessage(root1, 'ListOfListOfString');
+      const listOfListOfIntFields = getFieldNumbersFromMessage(root1, 'ListOfListOfInt');
+
+      // For nested wrappers, they should have a 'list' field (not 'items')
+      const stringListNumber = listOfListOfStringFields['list'];
+      const intListNumber = listOfListOfIntFields['list'];
+
+      // Verify nested wrapper types have the 'list' field with field number 1
+      expect(stringListNumber).toBe(1);
+      expect(intListNumber).toBe(1);
+
+      // Also verify the inner simple wrapper types exist
+      const listOfStringFields = getFieldNumbersFromMessage(root1, 'ListOfString');
+      const listOfIntFields = getFieldNumbersFromMessage(root1, 'ListOfInt');
+
+      const stringItemsNumber = listOfStringFields['items'];
+      const intItemsNumber = listOfIntFields['items'];
+
+      expect(stringItemsNumber).toBe(1);
+      expect(intItemsNumber).toBe(1);
+
+      // Get the generated lock data
+      const lockData = visitor1.getGeneratedLockData();
+      expect(lockData).not.toBeNull();
+
+      // Verify wrapper types are NOT in lock data (they're auto-generated with deterministic field numbers)
+      expect(lockData!.messages['ListOfListOfString']).toBeUndefined();
+      expect(lockData!.messages['ListOfListOfInt']).toBeUndefined();
+      expect(lockData!.messages['ListOfString']).toBeUndefined();
+      expect(lockData!.messages['ListOfInt']).toBeUndefined();
+
+      // Modified schema with additional nested lists
+      const modifiedSchema = buildSchema(`
+        type User {
+          id: ID!
+          name: String!
+          tagGroups: [[String]]      # existing nested nullable list
+          scoreMatrix: [[Int]]       # existing nested nullable list
+          userGroups: [[User]]       # new nested nullable list -> generates ListOfListOfUser wrapper
+        }
+        
+        type Query {
+          getUsers: [User]
+        }
+      `);
+
+      // Create another visitor using the generated lock data
+      const visitor2 = new GraphQLToProtoTextVisitor(modifiedSchema, {
+        serviceName: 'UserService',
+        lockData: lockData || undefined,
+      });
+
+      // Generate the second proto
+      const proto2 = visitor2.visit();
+
+      // Parse the proto with protobufjs
+      const root2 = loadProtoFromText(proto2);
+
+      // Verify existing wrapper types preserved their field numbers
+      const listOfListOfStringFields2 = getFieldNumbersFromMessage(root2, 'ListOfListOfString');
+      const listOfListOfIntFields2 = getFieldNumbersFromMessage(root2, 'ListOfListOfInt');
+      const listOfListOfUserFields2 = getFieldNumbersFromMessage(root2, 'ListOfListOfUser');
+
+      // Verify existing field numbers are preserved
+      expect(listOfListOfStringFields2['list']).toBe(stringListNumber);
+      expect(listOfListOfIntFields2['list']).toBe(intListNumber);
+
+      // Verify new nested wrapper type has field number 1
+      expect(listOfListOfUserFields2['list']).toBe(1);
+
+      // Verify simple wrapper types are still preserved
+      const listOfStringFields2 = getFieldNumbersFromMessage(root2, 'ListOfString');
+      const listOfIntFields2 = getFieldNumbersFromMessage(root2, 'ListOfInt');
+      const listOfUserFields2 = getFieldNumbersFromMessage(root2, 'ListOfUser');
+
+      expect(listOfStringFields2['items']).toBe(stringItemsNumber);
+      expect(listOfIntFields2['items']).toBe(intItemsNumber);
+      expect(listOfUserFields2['items']).toBe(1); // New simple wrapper for User
+    });
+
+    test('should handle mixed simple and nested wrapper types with field preservation', () => {
+      // Initial schema with both simple and nested nullable lists
+      const initialSchema = buildSchema(`
+        type User {
+          id: ID!
+          name: String!
+          tags: [String]             # simple nullable list -> ListOfString
+          nestedTags: [[String]]     # nested nullable list -> ListOfListOfString
+          friends: [User]            # simple nullable list -> ListOfUser  
+          friendGroups: [[User]]     # nested nullable list -> ListOfListOfUser
+        }
+        
+        type Query {
+          getUsers: [User]
+        }
+      `);
+
+      // Create the visitor with no initial lock data
+      const visitor1 = new GraphQLToProtoTextVisitor(initialSchema, {
+        serviceName: 'UserService',
+      });
+
+      // Generate the first proto
+      const proto1 = visitor1.visit();
+
+      // Parse the proto with protobufjs
+      const root1 = loadProtoFromText(proto1);
+
+      // Get field numbers for all wrapper types
+      const listOfStringFields = getFieldNumbersFromMessage(root1, 'ListOfString');
+      const listOfListOfStringFields = getFieldNumbersFromMessage(root1, 'ListOfListOfString');
+      const listOfUserFields = getFieldNumbersFromMessage(root1, 'ListOfUser');
+      const listOfListOfUserFields = getFieldNumbersFromMessage(root1, 'ListOfListOfUser');
+
+      // Store original field numbers
+      const stringItemsNumber = listOfStringFields['items'];
+      const stringListNumber = listOfListOfStringFields['list'];
+      const userItemsNumber = listOfUserFields['items'];
+      const userListNumber = listOfListOfUserFields['list'];
+
+      // Verify correct field types for different wrapper levels
+      expect(stringItemsNumber).toBe(1); // Simple wrapper has 'items'
+      expect(stringListNumber).toBe(1); // Nested wrapper has 'list'
+      expect(userItemsNumber).toBe(1); // Simple wrapper has 'items'
+      expect(userListNumber).toBe(1); // Nested wrapper has 'list'
+
+      // Get the generated lock data
+      const lockData = visitor1.getGeneratedLockData();
+      expect(lockData).not.toBeNull();
+
+      // Verify wrapper types are NOT in lock data (they're auto-generated with deterministic field numbers)
+      expect(lockData!.messages['ListOfString']).toBeUndefined();
+      expect(lockData!.messages['ListOfListOfString']).toBeUndefined();
+      expect(lockData!.messages['ListOfUser']).toBeUndefined();
+      expect(lockData!.messages['ListOfListOfUser']).toBeUndefined();
+
+      // Modified schema with some lists removed and new ones added
+      const modifiedSchema = buildSchema(`
+        type User {
+          id: ID!
+          name: String!
+          tags: [String]             # preserved
+          # nestedTags: [[String]]   # removed
+          friends: [User]            # preserved
+          friendGroups: [[User]]     # preserved
+          scores: [Int]              # new simple nullable list -> ListOfInt
+          # scoreMatrix: [[Int]]     # hypothetical nested list (not added yet)
+        }
+        
+        type Query {
+          getUsers: [User]
+        }
+      `);
+
+      // Create another visitor using the generated lock data
+      const visitor2 = new GraphQLToProtoTextVisitor(modifiedSchema, {
+        serviceName: 'UserService',
+        lockData: lockData || undefined,
+      });
+
+      // Generate the second proto
+      const proto2 = visitor2.visit();
+
+      // Parse the proto with protobufjs
+      const root2 = loadProtoFromText(proto2);
+
+      // Verify preserved wrapper types maintain their field numbers
+      const listOfStringFields2 = getFieldNumbersFromMessage(root2, 'ListOfString');
+      const listOfUserFields2 = getFieldNumbersFromMessage(root2, 'ListOfUser');
+      const listOfListOfUserFields2 = getFieldNumbersFromMessage(root2, 'ListOfListOfUser');
+      const listOfIntFields2 = getFieldNumbersFromMessage(root2, 'ListOfInt');
+
+      // Verify field numbers are preserved
+      expect(listOfStringFields2['items']).toBe(stringItemsNumber);
+      expect(listOfUserFields2['items']).toBe(userItemsNumber);
+      expect(listOfListOfUserFields2['list']).toBe(userListNumber);
+
+      // Verify new wrapper type has field number 1
+      expect(listOfIntFields2['items']).toBe(1);
+
+      // Verify removed wrapper type is not present
+      // Check if the removed wrapper type exists in the proto
+      let listOfListOfStringExists = false;
+      try {
+        root2.lookupType('ListOfListOfString');
+        listOfListOfStringExists = true;
+      } catch (e) {
+        // Type doesn't exist, which is expected when the field is removed
+        listOfListOfStringExists = false;
+      }
+      expect(listOfListOfStringExists).toBe(false); // Should not exist since nestedTags was removed
+    });
+  });
 });
diff --git a/protographic/tests/sdl-to-proto/11-lists.test.ts b/protographic/tests/sdl-to-proto/11-lists.test.ts
new file mode 100644
index 0000000000..ddb3d41d0e
--- /dev/null
+++ b/protographic/tests/sdl-to-proto/11-lists.test.ts
@@ -0,0 +1,2011 @@
+import { describe, expect, it } from 'vitest';
+import { compileGraphQLToProto } from '../../src';
+import { expectValidProto } from '../util';
+
+describe('SDL to Proto Lists', () => {
+  it('should correctly generate protobuf for types with a single non nullable list', () => {
+    const sdl = `
+        type User {
+            id: ID!
+            firstName: String!
+            middleNames: [String]!
+            lastName: String!
+            friends: [User!]!
+        }
+        
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+          "syntax = "proto3";
+          package service.v1;
+
+          // Service definition for DefaultService
+          service DefaultService {
+            rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+          }
+
+          // Request message for getUser operation.
+          message QueryGetUserRequest {
+          }
+          // Response message for getUser operation.
+          message QueryGetUserResponse {
+            User get_user = 1;
+          }
+
+          message User {
+            string id = 1;
+            string first_name = 2;
+            repeated string middle_names = 3;
+            string last_name = 4;
+            repeated User friends = 5;
+          }"
+        `);
+  });
+
+  it('should correctly generate protobuf for types with a single nullable list', () => {
+    const sdl = `
+        type User {
+            id: ID!
+            firstName: String!
+            middleNames: [String]
+            lastName: String!
+            friends: [User!]
+        }
+
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+          "syntax = "proto3";
+          package service.v1;
+
+          // Service definition for DefaultService
+          service DefaultService {
+            rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+          }
+
+          // Wrapper message for a list of String.
+          message ListOfString {
+            repeated string items = 1;
+          }
+
+          // Wrapper message for a list of User.
+          message ListOfUser {
+            repeated User items = 1;
+          }
+
+          // Request message for getUser operation.
+          message QueryGetUserRequest {
+          }
+          // Response message for getUser operation.
+          message QueryGetUserResponse {
+            User get_user = 1;
+          }
+
+          message User {
+            string id = 1;
+            string first_name = 2;
+            ListOfString middle_names = 3;
+            string last_name = 4;
+            ListOfUser friends = 5;
+          }"
+        `);
+  });
+
+  it('should correctly generate protobuf for types with a nested non nullable list', () => {
+    const sdl = `
+        type User {
+            middleNames: [[String]!]!
+            middleNames2: [[String]]!
+            friends: [[User!]!]!
+        }
+
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfUser {
+        message List {
+          repeated ListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
+      // Request message for getUser operation.
+      message QueryGetUserRequest {
+      }
+      // Response message for getUser operation.
+      message QueryGetUserResponse {
+        User get_user = 1;
+      }
+
+      message User {
+        ListOfListOfString middle_names = 1;
+        ListOfListOfString middle_names_2 = 2;
+        ListOfListOfUser friends = 3;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for types with a nested nullable list', () => {
+    const sdl = `
+        type User {
+            middleNames: [[String]!]
+            middleNames2: [[String]]
+            friends: [[User!]!]
+        }
+
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfUser {
+        message List {
+          repeated ListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
+      // Request message for getUser operation.
+      message QueryGetUserRequest {
+      }
+      // Response message for getUser operation.
+      message QueryGetUserResponse {
+        User get_user = 1;
+      }
+
+      message User {
+        ListOfListOfString middle_names = 1;
+        ListOfListOfString middle_names_2 = 2;
+        ListOfListOfUser friends = 3;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for types with mixed nullable, non nullable, nested and non nested lists', () => {
+    const sdl = `
+        type User {
+            firstNames: [String]!
+            lastNames: [String!]
+            middleNames: [[String]!]
+            middleNames2: [[String]]
+            friends: [[User!]!]
+            friends2: [User!]!
+        }
+
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfUser {
+        message List {
+          repeated ListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
+      // Request message for getUser operation.
+      message QueryGetUserRequest {
+      }
+      // Response message for getUser operation.
+      message QueryGetUserResponse {
+        User get_user = 1;
+      }
+
+      message User {
+        repeated string first_names = 1;
+        ListOfString last_names = 2;
+        ListOfListOfString middle_names = 3;
+        ListOfListOfString middle_names_2 = 4;
+        ListOfListOfUser friends = 5;
+        repeated User friends_2 = 6;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for lists with enums', () => {
+    const sdl = `
+        enum Status {
+            ACTIVE
+            INACTIVE
+            PENDING
+        }
+
+        type User {
+            id: ID!
+            statuses: [Status!]!
+            previousStatuses: [Status]
+            statusHistory: [[Status!]!]!
+            statusGroups: [[Status]]
+        }
+
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+      }
+
+      // Wrapper message for a list of Status.
+      message ListOfListOfStatus {
+        message List {
+          repeated ListOfStatus items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Status.
+      message ListOfStatus {
+        repeated Status items = 1;
+      }
+
+      // Request message for getUser operation.
+      message QueryGetUserRequest {
+      }
+      // Response message for getUser operation.
+      message QueryGetUserResponse {
+        User get_user = 1;
+      }
+
+      message User {
+        string id = 1;
+        repeated Status statuses = 2;
+        ListOfStatus previous_statuses = 3;
+        ListOfListOfStatus status_history = 4;
+        ListOfListOfStatus status_groups = 5;
+      }
+
+      enum Status {
+        STATUS_UNSPECIFIED = 0;
+        STATUS_ACTIVE = 1;
+        STATUS_INACTIVE = 2;
+        STATUS_PENDING = 3;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for lists with interfaces', () => {
+    const sdl = `
+        interface Node {
+            id: ID!
+        }
+
+        type User implements Node {
+            id: ID!
+            name: String!
+        }
+
+        type Post implements Node {
+            id: ID!
+            title: String!
+        }
+
+        type Timeline {
+            items: [Node!]!
+            optionalItems: [Node]
+            nestedItems: [[Node!]!]!
+            optionalNestedItems: [[Node]]
+        }
+
+        type Query {
+            getTimeline: Timeline!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetTimeline(QueryGetTimelineRequest) returns (QueryGetTimelineResponse) {}
+      }
+
+      // Wrapper message for a list of Node.
+      message ListOfListOfNode {
+        message List {
+          repeated ListOfNode items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Node.
+      message ListOfNode {
+        repeated Node items = 1;
+      }
+
+      // Request message for getTimeline operation.
+      message QueryGetTimelineRequest {
+      }
+      // Response message for getTimeline operation.
+      message QueryGetTimelineResponse {
+        Timeline get_timeline = 1;
+      }
+
+      message Timeline {
+        repeated Node items = 1;
+        ListOfNode optional_items = 2;
+        ListOfListOfNode nested_items = 3;
+        ListOfListOfNode optional_nested_items = 4;
+      }
+
+      message Node {
+        oneof instance {
+        User user = 1;
+        Post post = 2;
+        }
+      }
+
+      message User {
+        string id = 1;
+        string name = 2;
+      }
+
+      message Post {
+        string id = 1;
+        string title = 2;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for lists with unions', () => {
+    const sdl = `
+        type User {
+            id: ID!
+            name: String!
+        }
+
+        type Post {
+            id: ID!
+            title: String!
+        }
+
+        union SearchResult = User | Post
+
+        type SearchResults {
+            results: [SearchResult!]!
+            optionalResults: [SearchResult]
+            nestedResults: [[SearchResult!]!]!
+            optionalNestedResults: [[SearchResult]]
+        }
+
+        type Query {
+            search: SearchResults!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QuerySearch(QuerySearchRequest) returns (QuerySearchResponse) {}
+      }
+
+      // Wrapper message for a list of SearchResult.
+      message ListOfListOfSearchResult {
+        message List {
+          repeated ListOfSearchResult items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of SearchResult.
+      message ListOfSearchResult {
+        repeated SearchResult items = 1;
+      }
+
+      // Request message for search operation.
+      message QuerySearchRequest {
+      }
+      // Response message for search operation.
+      message QuerySearchResponse {
+        SearchResults search = 1;
+      }
+
+      message SearchResults {
+        repeated SearchResult results = 1;
+        ListOfSearchResult optional_results = 2;
+        ListOfListOfSearchResult nested_results = 3;
+        ListOfListOfSearchResult optional_nested_results = 4;
+      }
+
+      message User {
+        string id = 1;
+        string name = 2;
+      }
+
+      message Post {
+        string id = 1;
+        string title = 2;
+      }
+
+      message SearchResult {
+        oneof value {
+        User user = 1;
+        Post post = 2;
+        }
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for lists with scalars and custom scalars', () => {
+    const sdl = `
+        scalar DateTime
+        scalar JSON
+
+        type User {
+            id: ID!
+            tags: [String!]!
+            optionalTags: [String]
+            scores: [Int!]!
+            optionalScores: [Int]
+            ratings: [Float!]!
+            optionalRatings: [Float]
+            timestamps: [DateTime!]!
+            optionalTimestamps: [DateTime]
+            metadata: [JSON!]!
+            optionalMetadata: [JSON]
+            nestedTags: [[String!]!]!
+            nestedOptionalTags: [[String]]
+        }
+
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+      }
+
+      // Wrapper message for a list of DateTime.
+      message ListOfDateTime {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of Float.
+      message ListOfFloat {
+        repeated double items = 1;
+      }
+
+      // Wrapper message for a list of Int.
+      message ListOfInt {
+        repeated int32 items = 1;
+      }
+
+      // Wrapper message for a list of JSON.
+      message ListOfJSON {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Request message for getUser operation.
+      message QueryGetUserRequest {
+      }
+      // Response message for getUser operation.
+      message QueryGetUserResponse {
+        User get_user = 1;
+      }
+
+      message User {
+        string id = 1;
+        repeated string tags = 2;
+        ListOfString optional_tags = 3;
+        repeated int32 scores = 4;
+        ListOfInt optional_scores = 5;
+        repeated double ratings = 6;
+        ListOfFloat optional_ratings = 7;
+        repeated string timestamps = 8;
+        ListOfDateTime optional_timestamps = 9;
+        repeated string metadata = 10;
+        ListOfJSON optional_metadata = 11;
+        ListOfListOfString nested_tags = 12;
+        ListOfListOfString nested_optional_tags = 13;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for deeply nested lists', () => {
+    const sdl = `
+        type User {
+            id: ID!
+            name: String!
+        }
+
+        type Matrix {
+            level1: [[[String!]!]!]!
+            level2: [[[User!]!]!]!
+            level3: [[[[String]]]]
+            level4: [[[[[User!]!]!]!]!]!
+        }
+
+        type Query {
+            getMatrix: Matrix!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetMatrix(QueryGetMatrixRequest) returns (QueryGetMatrixResponse) {}
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfListOfListOfListOfUser {
+        message List {
+          repeated ListOfListOfListOfListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfListOfListOfString {
+        message List {
+          repeated ListOfListOfListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfListOfListOfUser {
+        message List {
+          repeated ListOfListOfListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfListOfString {
+        message List {
+          repeated ListOfListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfListOfUser {
+        message List {
+          repeated ListOfListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfUser {
+        message List {
+          repeated ListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
+      // Request message for getMatrix operation.
+      message QueryGetMatrixRequest {
+      }
+      // Response message for getMatrix operation.
+      message QueryGetMatrixResponse {
+        Matrix get_matrix = 1;
+      }
+
+      message Matrix {
+        ListOfListOfListOfString level_1 = 1;
+        ListOfListOfListOfUser level_2 = 2;
+        ListOfListOfListOfListOfString level_3 = 3;
+        ListOfListOfListOfListOfListOfUser level_4 = 4;
+      }
+
+      message User {
+        string id = 1;
+        string name = 2;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for lists with input types in mutations', () => {
+    const sdl = `
+        input CreateUserInput {
+            name: String!
+            tags: [String!]!
+            optionalTags: [String]
+        }
+
+        input UpdateUserInput {
+            id: ID!
+            name: String
+            addTags: [String!]
+            removeTags: [String]
+        }
+
+        type User {
+            id: ID!
+            name: String!
+            tags: [String!]!
+        }
+
+        type Mutation {
+            createUser(input: CreateUserInput!): User!
+            createUsers(inputs: [CreateUserInput!]!): [User!]!
+            updateUsers(inputs: [UpdateUserInput!]!): [User!]!
+            bulkUpdate(updates: [[UpdateUserInput!]!]!): [User!]!
+        }
+
+        type Query {
+            getUser: User!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      import "google/protobuf/wrappers.proto";
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc MutationBulkUpdate(MutationBulkUpdateRequest) returns (MutationBulkUpdateResponse) {}
+        rpc MutationCreateUser(MutationCreateUserRequest) returns (MutationCreateUserResponse) {}
+        rpc MutationCreateUsers(MutationCreateUsersRequest) returns (MutationCreateUsersResponse) {}
+        rpc MutationUpdateUsers(MutationUpdateUsersRequest) returns (MutationUpdateUsersResponse) {}
+        rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+      }
+
+      // Wrapper message for a list of UpdateUserInput.
+      message ListOfListOfUpdateUserInput {
+        message List {
+          repeated ListOfUpdateUserInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of UpdateUserInput.
+      message ListOfUpdateUserInput {
+        repeated UpdateUserInput items = 1;
+      }
+
+      // Request message for getUser operation.
+      message QueryGetUserRequest {
+      }
+      // Response message for getUser operation.
+      message QueryGetUserResponse {
+        User get_user = 1;
+      }
+      // Request message for createUser operation.
+      message MutationCreateUserRequest {
+        CreateUserInput input = 1;
+      }
+      // Response message for createUser operation.
+      message MutationCreateUserResponse {
+        User create_user = 1;
+      }
+      // Request message for createUsers operation.
+      message MutationCreateUsersRequest {
+        repeated CreateUserInput inputs = 1;
+      }
+      // Response message for createUsers operation.
+      message MutationCreateUsersResponse {
+        repeated User create_users = 1;
+      }
+      // Request message for updateUsers operation.
+      message MutationUpdateUsersRequest {
+        repeated UpdateUserInput inputs = 1;
+      }
+      // Response message for updateUsers operation.
+      message MutationUpdateUsersResponse {
+        repeated User update_users = 1;
+      }
+      // Request message for bulkUpdate operation.
+      message MutationBulkUpdateRequest {
+        ListOfListOfUpdateUserInput updates = 1;
+      }
+      // Response message for bulkUpdate operation.
+      message MutationBulkUpdateResponse {
+        repeated User bulk_update = 1;
+      }
+
+      message User {
+        string id = 1;
+        string name = 2;
+        repeated string tags = 3;
+      }
+
+      message CreateUserInput {
+        string name = 1;
+        repeated string tags = 2;
+        ListOfString optional_tags = 3;
+      }
+
+      message UpdateUserInput {
+        string id = 1;
+        google.protobuf.StringValue name = 2;
+        ListOfString add_tags = 3;
+        ListOfString remove_tags = 4;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for mixed complex lists with all types', () => {
+    const sdl = `
+        enum Priority {
+            LOW
+            MEDIUM
+            HIGH
+        }
+
+        scalar DateTime
+
+        interface Node {
+            id: ID!
+        }
+
+        type User implements Node {
+            id: ID!
+            name: String!
+        }
+
+        type Task implements Node {
+            id: ID!
+            title: String!
+        }
+
+        union Item = User | Task
+
+        input FilterInput {
+            priorities: [Priority!]
+            userIds: [ID]
+        }
+
+        type ComplexType {
+            # Simple lists
+            strings: [String!]!
+            optionalStrings: [String]
+            
+            # Enum lists
+            priorities: [Priority!]!
+            optionalPriorities: [Priority]
+            
+            # Interface lists
+            nodes: [Node!]!
+            optionalNodes: [Node]
+            
+            # Union lists
+            items: [Item!]!
+            optionalItems: [Item]
+            
+            # Nested lists
+            nestedStrings: [[String!]!]!
+            nestedOptionalStrings: [[String]]
+            nestedPriorities: [[Priority!]!]!
+            nestedOptionalPriorities: [[Priority]]
+            
+            # Complex nested
+            deepNestedItems: [[[Item!]!]!]!
+            mixedNested: [[[[Priority]]]]
+        }
+
+        type Query {
+            getComplex(filter: FilterInput): ComplexType!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetComplex(QueryGetComplexRequest) returns (QueryGetComplexResponse) {}
+      }
+
+      // Wrapper message for a list of ID.
+      message ListOfID {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of Item.
+      message ListOfItem {
+        repeated Item items = 1;
+      }
+
+      // Wrapper message for a list of Item.
+      message ListOfListOfItem {
+        message List {
+          repeated ListOfItem items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Item.
+      message ListOfListOfListOfItem {
+        message List {
+          repeated ListOfListOfItem items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Priority.
+      message ListOfListOfListOfListOfPriority {
+        message List {
+          repeated ListOfListOfListOfPriority items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Priority.
+      message ListOfListOfListOfPriority {
+        message List {
+          repeated ListOfListOfPriority items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Priority.
+      message ListOfListOfPriority {
+        message List {
+          repeated ListOfPriority items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Node.
+      message ListOfNode {
+        repeated Node items = 1;
+      }
+
+      // Wrapper message for a list of Priority.
+      message ListOfPriority {
+        repeated Priority items = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Request message for getComplex operation.
+      message QueryGetComplexRequest {
+        FilterInput filter = 1;
+      }
+      // Response message for getComplex operation.
+      message QueryGetComplexResponse {
+        ComplexType get_complex = 1;
+      }
+
+      message FilterInput {
+        ListOfPriority priorities = 1;
+        ListOfID user_ids = 2;
+      }
+
+      message ComplexType {
+        repeated string strings = 1;
+        ListOfString optional_strings = 2;
+        repeated Priority priorities = 3;
+        ListOfPriority optional_priorities = 4;
+        repeated Node nodes = 5;
+        ListOfNode optional_nodes = 6;
+        repeated Item items = 7;
+        ListOfItem optional_items = 8;
+        ListOfListOfString nested_strings = 9;
+        ListOfListOfString nested_optional_strings = 10;
+        ListOfListOfPriority nested_priorities = 11;
+        ListOfListOfPriority nested_optional_priorities = 12;
+        ListOfListOfListOfItem deep_nested_items = 13;
+        ListOfListOfListOfListOfPriority mixed_nested = 14;
+      }
+
+      enum Priority {
+        PRIORITY_UNSPECIFIED = 0;
+        PRIORITY_LOW = 1;
+        PRIORITY_MEDIUM = 2;
+        PRIORITY_HIGH = 3;
+      }
+
+      message Node {
+        oneof instance {
+        User user = 1;
+        Task task = 2;
+        }
+      }
+
+      message User {
+        string id = 1;
+        string name = 2;
+      }
+
+      message Task {
+        string id = 1;
+        string title = 2;
+      }
+
+      message Item {
+        oneof value {
+        User user = 1;
+        Task task = 2;
+        }
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for edge cases with empty lists and optional nesting', () => {
+    const sdl = `
+        type User {
+            id: ID!
+        }
+
+        type EdgeCases {
+            # Various nullable combinations
+            case1: [String!]
+            case2: [String]!
+            case3: [String]
+            
+            # Nested nullable combinations
+            case4: [[String!]!]
+            case5: [[String!]]!
+            case6: [[String!]]
+            case7: [[String]!]!
+            case8: [[String]!]
+            case9: [[String]]!
+            case10: [[String]]
+            
+            # With objects
+            users1: [User!]
+            users2: [User]!
+            users3: [User]
+            nestedUsers1: [[User!]!]
+            nestedUsers2: [[User!]]
+            nestedUsers3: [[User]!]
+            nestedUsers4: [[User]]
+        }
+
+        type Query {
+            getEdgeCases: EdgeCases!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetEdgeCases(QueryGetEdgeCasesRequest) returns (QueryGetEdgeCasesResponse) {}
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfUser {
+        message List {
+          repeated ListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
+      // Request message for getEdgeCases operation.
+      message QueryGetEdgeCasesRequest {
+      }
+      // Response message for getEdgeCases operation.
+      message QueryGetEdgeCasesResponse {
+        EdgeCases get_edge_cases = 1;
+      }
+
+      message EdgeCases {
+        ListOfString case_1 = 1;
+        repeated string case_2 = 2;
+        ListOfString case_3 = 3;
+        ListOfListOfString case_4 = 4;
+        ListOfListOfString case_5 = 5;
+        ListOfListOfString case_6 = 6;
+        ListOfListOfString case_7 = 7;
+        ListOfListOfString case_8 = 8;
+        ListOfListOfString case_9 = 9;
+        ListOfListOfString case_10 = 10;
+        ListOfUser users_1 = 11;
+        repeated User users_2 = 12;
+        ListOfUser users_3 = 13;
+        ListOfListOfUser nested_users_1 = 14;
+        ListOfListOfUser nested_users_2 = 15;
+        ListOfListOfUser nested_users_3 = 16;
+        ListOfListOfUser nested_users_4 = 17;
+      }
+
+      message User {
+        string id = 1;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for recursive types with lists', () => {
+    const sdl = `
+        type User {
+            id: ID!
+            name: String!
+            friends: [User!]!
+            optionalFriends: [User]
+            nestedFriendGroups: [[User!]!]!
+            optionalNestedFriendGroups: [[User]]
+        }
+
+        type Comment {
+            id: ID!
+            content: String!
+            author: User!
+            replies: [Comment!]!
+            optionalReplies: [Comment]
+            nestedReplies: [[Comment!]!]!
+        }
+
+        type Category {
+            id: ID!
+            name: String!
+            parent: Category
+            children: [Category!]!
+            optionalChildren: [Category]
+            subCategories: [[Category!]!]!
+            relatedCategories: [Category]
+        }
+
+        type Query {
+            getUser: User!
+            getComment: Comment!
+            getCategory: Category!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc QueryGetCategory(QueryGetCategoryRequest) returns (QueryGetCategoryResponse) {}
+        rpc QueryGetComment(QueryGetCommentRequest) returns (QueryGetCommentResponse) {}
+        rpc QueryGetUser(QueryGetUserRequest) returns (QueryGetUserResponse) {}
+      }
+
+      // Wrapper message for a list of Category.
+      message ListOfCategory {
+        repeated Category items = 1;
+      }
+
+      // Wrapper message for a list of Comment.
+      message ListOfComment {
+        repeated Comment items = 1;
+      }
+
+      // Wrapper message for a list of Category.
+      message ListOfListOfCategory {
+        message List {
+          repeated ListOfCategory items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of Comment.
+      message ListOfListOfComment {
+        message List {
+          repeated ListOfComment items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfListOfUser {
+        message List {
+          repeated ListOfUser items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of User.
+      message ListOfUser {
+        repeated User items = 1;
+      }
+
+      // Request message for getUser operation.
+      message QueryGetUserRequest {
+      }
+      // Response message for getUser operation.
+      message QueryGetUserResponse {
+        User get_user = 1;
+      }
+      // Request message for getComment operation.
+      message QueryGetCommentRequest {
+      }
+      // Response message for getComment operation.
+      message QueryGetCommentResponse {
+        Comment get_comment = 1;
+      }
+      // Request message for getCategory operation.
+      message QueryGetCategoryRequest {
+      }
+      // Response message for getCategory operation.
+      message QueryGetCategoryResponse {
+        Category get_category = 1;
+      }
+
+      message User {
+        string id = 1;
+        string name = 2;
+        repeated User friends = 3;
+        ListOfUser optional_friends = 4;
+        ListOfListOfUser nested_friend_groups = 5;
+        ListOfListOfUser optional_nested_friend_groups = 6;
+      }
+
+      message Comment {
+        string id = 1;
+        string content = 2;
+        User author = 3;
+        repeated Comment replies = 4;
+        ListOfComment optional_replies = 5;
+        ListOfListOfComment nested_replies = 6;
+      }
+
+      message Category {
+        string id = 1;
+        string name = 2;
+        Category parent = 3;
+        repeated Category children = 4;
+        ListOfCategory optional_children = 5;
+        ListOfListOfCategory sub_categories = 6;
+        ListOfCategory related_categories = 7;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for complex input types with lists', () => {
+    const sdl = `
+        input TagInput {
+            name: String!
+            weight: Float
+        }
+
+        input UserFilterInput {
+            ids: [ID!]
+            optionalIds: [ID]
+            tags: [TagInput!]!
+            optionalTags: [TagInput]
+            nestedTags: [[TagInput!]!]!
+            optionalNestedTags: [[TagInput]]
+            names: [String!]
+            scores: [Int]
+            ratings: [Float!]
+        }
+
+        input SortInput {
+            field: String!
+            direction: String!
+        }
+
+        input PaginationInput {
+            limit: Int
+            offset: Int
+        }
+
+        input SearchInput {
+            query: String!
+            filters: [UserFilterInput!]!
+            optionalFilters: [UserFilterInput]
+            nestedFilters: [[UserFilterInput!]!]!
+            sorts: [SortInput!]
+            pagination: PaginationInput
+        }
+
+        type User {
+            id: ID!
+            name: String!
+            tags: [String!]!
+        }
+
+        type SearchResult {
+            users: [User!]!
+            total: Int!
+        }
+
+        type Query {
+            searchUsers(input: SearchInput!): SearchResult!
+        }
+
+        type Mutation {
+            updateUsers(updates: [UserFilterInput!]!): [User!]!
+            bulkSearch(searches: [SearchInput!]!): [SearchResult!]!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      import "google/protobuf/wrappers.proto";
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc MutationBulkSearch(MutationBulkSearchRequest) returns (MutationBulkSearchResponse) {}
+        rpc MutationUpdateUsers(MutationUpdateUsersRequest) returns (MutationUpdateUsersResponse) {}
+        rpc QuerySearchUsers(QuerySearchUsersRequest) returns (QuerySearchUsersResponse) {}
+      }
+
+      // Wrapper message for a list of Float.
+      message ListOfFloat {
+        repeated double items = 1;
+      }
+
+      // Wrapper message for a list of ID.
+      message ListOfID {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of Int.
+      message ListOfInt {
+        repeated int32 items = 1;
+      }
+
+      // Wrapper message for a list of TagInput.
+      message ListOfListOfTagInput {
+        message List {
+          repeated ListOfTagInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of UserFilterInput.
+      message ListOfListOfUserFilterInput {
+        message List {
+          repeated ListOfUserFilterInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of SortInput.
+      message ListOfSortInput {
+        repeated SortInput items = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of TagInput.
+      message ListOfTagInput {
+        repeated TagInput items = 1;
+      }
+
+      // Wrapper message for a list of UserFilterInput.
+      message ListOfUserFilterInput {
+        repeated UserFilterInput items = 1;
+      }
+
+      // Request message for searchUsers operation.
+      message QuerySearchUsersRequest {
+        SearchInput input = 1;
+      }
+      // Response message for searchUsers operation.
+      message QuerySearchUsersResponse {
+        SearchResult search_users = 1;
+      }
+      // Request message for updateUsers operation.
+      message MutationUpdateUsersRequest {
+        repeated UserFilterInput updates = 1;
+      }
+      // Response message for updateUsers operation.
+      message MutationUpdateUsersResponse {
+        repeated User update_users = 1;
+      }
+      // Request message for bulkSearch operation.
+      message MutationBulkSearchRequest {
+        repeated SearchInput searches = 1;
+      }
+      // Response message for bulkSearch operation.
+      message MutationBulkSearchResponse {
+        repeated SearchResult bulk_search = 1;
+      }
+
+      message SearchInput {
+        string query = 1;
+        repeated UserFilterInput filters = 2;
+        ListOfUserFilterInput optional_filters = 3;
+        ListOfListOfUserFilterInput nested_filters = 4;
+        ListOfSortInput sorts = 5;
+        PaginationInput pagination = 6;
+      }
+
+      message SearchResult {
+        repeated User users = 1;
+        int32 total = 2;
+      }
+
+      message UserFilterInput {
+        ListOfID ids = 1;
+        ListOfID optional_ids = 2;
+        repeated TagInput tags = 3;
+        ListOfTagInput optional_tags = 4;
+        ListOfListOfTagInput nested_tags = 5;
+        ListOfListOfTagInput optional_nested_tags = 6;
+        ListOfString names = 7;
+        ListOfInt scores = 8;
+        ListOfFloat ratings = 9;
+      }
+
+      message User {
+        string id = 1;
+        string name = 2;
+        repeated string tags = 3;
+      }
+
+      message TagInput {
+        string name = 1;
+        google.protobuf.DoubleValue weight = 2;
+      }
+
+      message SortInput {
+        string field = 1;
+        string direction = 2;
+      }
+
+      message PaginationInput {
+        google.protobuf.Int32Value limit = 1;
+        google.protobuf.Int32Value offset = 2;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for recursive input types', () => {
+    const sdl = `
+        input CategoryInput {
+            id: ID!
+            name: String!
+            parentId: ID
+            children: [CategoryInput!]
+            optionalChildren: [CategoryInput]
+            nestedChildren: [[CategoryInput!]!]
+        }
+
+        input CommentInput {
+            id: ID!
+            content: String!
+            authorId: ID!
+            replies: [CommentInput!]!
+            optionalReplies: [CommentInput]
+            nestedReplies: [[CommentInput!]!]!
+        }
+
+        input FilterNodeInput {
+            field: String!
+            value: String!
+            operator: String!
+            children: [FilterNodeInput!]
+            optionalChildren: [FilterNodeInput]
+            andConditions: [[FilterNodeInput!]!]
+            orConditions: [[FilterNodeInput]]
+        }
+
+        type Category {
+            id: ID!
+            name: String!
+        }
+
+        type Comment {
+            id: ID!
+            content: String!
+        }
+
+        type FilterResult {
+            matched: Boolean!
+            count: Int!
+        }
+
+        type Query {
+            getCategory: Category!
+        }
+
+        type Mutation {
+            createCategory(input: CategoryInput!): Category!
+            createCategories(inputs: [CategoryInput!]!): [Category!]!
+            createComment(input: CommentInput!): Comment!
+            createComments(inputs: [CommentInput!]!): [Comment!]!
+            applyFilter(filter: FilterNodeInput!): FilterResult!
+            applyFilters(filters: [FilterNodeInput!]!): [FilterResult!]!
+            complexFilter(filters: [[FilterNodeInput!]!]!): FilterResult!
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      import "google/protobuf/wrappers.proto";
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc MutationApplyFilter(MutationApplyFilterRequest) returns (MutationApplyFilterResponse) {}
+        rpc MutationApplyFilters(MutationApplyFiltersRequest) returns (MutationApplyFiltersResponse) {}
+        rpc MutationComplexFilter(MutationComplexFilterRequest) returns (MutationComplexFilterResponse) {}
+        rpc MutationCreateCategories(MutationCreateCategoriesRequest) returns (MutationCreateCategoriesResponse) {}
+        rpc MutationCreateCategory(MutationCreateCategoryRequest) returns (MutationCreateCategoryResponse) {}
+        rpc MutationCreateComment(MutationCreateCommentRequest) returns (MutationCreateCommentResponse) {}
+        rpc MutationCreateComments(MutationCreateCommentsRequest) returns (MutationCreateCommentsResponse) {}
+        rpc QueryGetCategory(QueryGetCategoryRequest) returns (QueryGetCategoryResponse) {}
+      }
+
+      // Wrapper message for a list of CategoryInput.
+      message ListOfCategoryInput {
+        repeated CategoryInput items = 1;
+      }
+
+      // Wrapper message for a list of CommentInput.
+      message ListOfCommentInput {
+        repeated CommentInput items = 1;
+      }
+
+      // Wrapper message for a list of FilterNodeInput.
+      message ListOfFilterNodeInput {
+        repeated FilterNodeInput items = 1;
+      }
+
+      // Wrapper message for a list of CategoryInput.
+      message ListOfListOfCategoryInput {
+        message List {
+          repeated ListOfCategoryInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of CommentInput.
+      message ListOfListOfCommentInput {
+        message List {
+          repeated ListOfCommentInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of FilterNodeInput.
+      message ListOfListOfFilterNodeInput {
+        message List {
+          repeated ListOfFilterNodeInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Request message for getCategory operation.
+      message QueryGetCategoryRequest {
+      }
+      // Response message for getCategory operation.
+      message QueryGetCategoryResponse {
+        Category get_category = 1;
+      }
+      // Request message for createCategory operation.
+      message MutationCreateCategoryRequest {
+        CategoryInput input = 1;
+      }
+      // Response message for createCategory operation.
+      message MutationCreateCategoryResponse {
+        Category create_category = 1;
+      }
+      // Request message for createCategories operation.
+      message MutationCreateCategoriesRequest {
+        repeated CategoryInput inputs = 1;
+      }
+      // Response message for createCategories operation.
+      message MutationCreateCategoriesResponse {
+        repeated Category create_categories = 1;
+      }
+      // Request message for createComment operation.
+      message MutationCreateCommentRequest {
+        CommentInput input = 1;
+      }
+      // Response message for createComment operation.
+      message MutationCreateCommentResponse {
+        Comment create_comment = 1;
+      }
+      // Request message for createComments operation.
+      message MutationCreateCommentsRequest {
+        repeated CommentInput inputs = 1;
+      }
+      // Response message for createComments operation.
+      message MutationCreateCommentsResponse {
+        repeated Comment create_comments = 1;
+      }
+      // Request message for applyFilter operation.
+      message MutationApplyFilterRequest {
+        FilterNodeInput filter = 1;
+      }
+      // Response message for applyFilter operation.
+      message MutationApplyFilterResponse {
+        FilterResult apply_filter = 1;
+      }
+      // Request message for applyFilters operation.
+      message MutationApplyFiltersRequest {
+        repeated FilterNodeInput filters = 1;
+      }
+      // Response message for applyFilters operation.
+      message MutationApplyFiltersResponse {
+        repeated FilterResult apply_filters = 1;
+      }
+      // Request message for complexFilter operation.
+      message MutationComplexFilterRequest {
+        ListOfListOfFilterNodeInput filters = 1;
+      }
+      // Response message for complexFilter operation.
+      message MutationComplexFilterResponse {
+        FilterResult complex_filter = 1;
+      }
+
+      message Category {
+        string id = 1;
+        string name = 2;
+      }
+
+      message CategoryInput {
+        string id = 1;
+        string name = 2;
+        google.protobuf.StringValue parent_id = 3;
+        ListOfCategoryInput children = 4;
+        ListOfCategoryInput optional_children = 5;
+        ListOfListOfCategoryInput nested_children = 6;
+      }
+
+      message CommentInput {
+        string id = 1;
+        string content = 2;
+        string author_id = 3;
+        repeated CommentInput replies = 4;
+        ListOfCommentInput optional_replies = 5;
+        ListOfListOfCommentInput nested_replies = 6;
+      }
+
+      message Comment {
+        string id = 1;
+        string content = 2;
+      }
+
+      message FilterNodeInput {
+        string field = 1;
+        string value = 2;
+        string operator = 3;
+        ListOfFilterNodeInput children = 4;
+        ListOfFilterNodeInput optional_children = 5;
+        ListOfListOfFilterNodeInput and_conditions = 6;
+        ListOfListOfFilterNodeInput or_conditions = 7;
+      }
+
+      message FilterResult {
+        bool matched = 1;
+        int32 count = 2;
+      }"
+    `);
+  });
+
+  it('should correctly generate protobuf for mixed recursive and non-recursive types with complex list nesting', () => {
+    const sdl = `
+        enum Status {
+            ACTIVE
+            INACTIVE
+            PENDING
+        }
+
+        scalar DateTime
+
+        input MetadataInput {
+            key: String!
+            value: String!
+            tags: [String!]
+            nestedData: [MetadataInput]
+        }
+
+        input TreeNodeInput {
+            id: ID!
+            value: String!
+            status: Status!
+            metadata: [MetadataInput!]
+            children: [TreeNodeInput!]
+            optionalChildren: [TreeNodeInput]
+            nestedChildren: [[TreeNodeInput!]!]
+            siblingGroups: [[[TreeNodeInput]]]
+        }
+
+        type TreeNode {
+            id: ID!
+            value: String!
+            status: Status!
+            children: [TreeNode!]!
+            optionalChildren: [TreeNode]
+            nestedChildren: [[TreeNode!]!]!
+            parent: TreeNode
+            ancestors: [TreeNode!]!
+            descendants: [[TreeNode]]
+        }
+
+        type ProcessingResult {
+            nodes: [TreeNode!]!
+            errors: [String]
+            warnings: [[String]]
+            metadata: [String!]!
+        }
+
+        type Query {
+            getTree: TreeNode!
+        }
+
+        type Mutation {
+            processTree(input: TreeNodeInput!): ProcessingResult!
+            processTrees(inputs: [TreeNodeInput!]!): [ProcessingResult!]!
+            bulkProcess(batches: [[TreeNodeInput!]!]!): ProcessingResult!
+            complexProcess(data: [[[TreeNodeInput]]]!): [ProcessingResult]
+        }`;
+
+    const { proto: protoText } = compileGraphQLToProto(sdl);
+
+    expectValidProto(protoText);
+
+    expect(protoText).toMatchInlineSnapshot(`
+      "syntax = "proto3";
+      package service.v1;
+
+      // Service definition for DefaultService
+      service DefaultService {
+        rpc MutationBulkProcess(MutationBulkProcessRequest) returns (MutationBulkProcessResponse) {}
+        rpc MutationComplexProcess(MutationComplexProcessRequest) returns (MutationComplexProcessResponse) {}
+        rpc MutationProcessTree(MutationProcessTreeRequest) returns (MutationProcessTreeResponse) {}
+        rpc MutationProcessTrees(MutationProcessTreesRequest) returns (MutationProcessTreesResponse) {}
+        rpc QueryGetTree(QueryGetTreeRequest) returns (QueryGetTreeResponse) {}
+      }
+
+      // Wrapper message for a list of TreeNodeInput.
+      message ListOfListOfListOfTreeNodeInput {
+        message List {
+          repeated ListOfListOfTreeNodeInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfListOfString {
+        message List {
+          repeated ListOfString items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of TreeNode.
+      message ListOfListOfTreeNode {
+        message List {
+          repeated ListOfTreeNode items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of TreeNodeInput.
+      message ListOfListOfTreeNodeInput {
+        message List {
+          repeated ListOfTreeNodeInput items = 1;
+        }
+        List list = 1;
+      }
+
+      // Wrapper message for a list of MetadataInput.
+      message ListOfMetadataInput {
+        repeated MetadataInput items = 1;
+      }
+
+      // Wrapper message for a list of ProcessingResult.
+      message ListOfProcessingResult {
+        repeated ProcessingResult items = 1;
+      }
+
+      // Wrapper message for a list of String.
+      message ListOfString {
+        repeated string items = 1;
+      }
+
+      // Wrapper message for a list of TreeNode.
+      message ListOfTreeNode {
+        repeated TreeNode items = 1;
+      }
+
+      // Wrapper message for a list of TreeNodeInput.
+      message ListOfTreeNodeInput {
+        repeated TreeNodeInput items = 1;
+      }
+
+      // Request message for getTree operation.
+      message QueryGetTreeRequest {
+      }
+      // Response message for getTree operation.
+      message QueryGetTreeResponse {
+        TreeNode get_tree = 1;
+      }
+      // Request message for processTree operation.
+      message MutationProcessTreeRequest {
+        TreeNodeInput input = 1;
+      }
+      // Response message for processTree operation.
+      message MutationProcessTreeResponse {
+        ProcessingResult process_tree = 1;
+      }
+      // Request message for processTrees operation.
+      message MutationProcessTreesRequest {
+        repeated TreeNodeInput inputs = 1;
+      }
+      // Response message for processTrees operation.
+      message MutationProcessTreesResponse {
+        repeated ProcessingResult process_trees = 1;
+      }
+      // Request message for bulkProcess operation.
+      message MutationBulkProcessRequest {
+        ListOfListOfTreeNodeInput batches = 1;
+      }
+      // Response message for bulkProcess operation.
+      message MutationBulkProcessResponse {
+        ProcessingResult bulk_process = 1;
+      }
+      // Request message for complexProcess operation.
+      message MutationComplexProcessRequest {
+        ListOfListOfListOfTreeNodeInput data = 1;
+      }
+      // Response message for complexProcess operation.
+      message MutationComplexProcessResponse {
+        ListOfProcessingResult complex_process = 1;
+      }
+
+      message TreeNode {
+        string id = 1;
+        string value = 2;
+        Status status = 3;
+        repeated TreeNode children = 4;
+        ListOfTreeNode optional_children = 5;
+        ListOfListOfTreeNode nested_children = 6;
+        TreeNode parent = 7;
+        repeated TreeNode ancestors = 8;
+        ListOfListOfTreeNode descendants = 9;
+      }
+
+      message TreeNodeInput {
+        string id = 1;
+        string value = 2;
+        Status status = 3;
+        ListOfMetadataInput metadata = 4;
+        ListOfTreeNodeInput children = 5;
+        ListOfTreeNodeInput optional_children = 6;
+        ListOfListOfTreeNodeInput nested_children = 7;
+        ListOfListOfListOfTreeNodeInput sibling_groups = 8;
+      }
+
+      message ProcessingResult {
+        repeated TreeNode nodes = 1;
+        ListOfString errors = 2;
+        ListOfListOfString warnings = 3;
+        repeated string metadata = 4;
+      }
+
+      enum Status {
+        STATUS_UNSPECIFIED = 0;
+        STATUS_ACTIVE = 1;
+        STATUS_INACTIVE = 2;
+        STATUS_PENDING = 3;
+      }
+
+      message MetadataInput {
+        string key = 1;
+        string value = 2;
+        ListOfString tags = 3;
+        ListOfMetadataInput nested_data = 4;
+      }"
+    `);
+  });
+});
diff --git a/vitest.workspace.ts b/vitest.workspace.ts
index b664ff164c..8f75c72b4b 100644
--- a/vitest.workspace.ts
+++ b/vitest.workspace.ts
@@ -1 +1 @@
-export default ['controlplane', 'shared', 'cli', 'composition'];
+export default ['controlplane', 'shared', 'cli', 'composition', 'protographic'];