diff --git a/bun.lockb b/bun.lockb
index 3ae2d19..90df432 100755
Binary files a/bun.lockb and b/bun.lockb differ
diff --git a/docs/docs/configuration.md b/docs/docs/configuration.md
index 105da11..052ebe4 100644
--- a/docs/docs/configuration.md
+++ b/docs/docs/configuration.md
@@ -5,5 +5,5 @@ sidebar_position: 3
 # Configuration
 
 ```ts reference title="Config Schema"
-https://github.com/ExpediaGroup/graphql-kotlin-codegen/blob/main/src/config.ts#L17-L100000
+https://github.com/ExpediaGroup/graphql-kotlin-codegen/blob/main/src/config.ts#L1-L100000
 ```
diff --git a/eslint.config.js b/eslint.config.js
index 03d7dab..09c7cc4 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -13,6 +13,7 @@ export default [
       },
     },
     rules: {
+      "no-console": "error",
       "@typescript-eslint/no-non-null-assertion": "error",
       "@typescript-eslint/no-unsafe-argument": "error",
       "@typescript-eslint/no-unsafe-call": "error",
diff --git a/package.json b/package.json
index 45be384..fd1913f 100644
--- a/package.json
+++ b/package.json
@@ -28,7 +28,7 @@
     "@graphql-codegen/cli": "5.0.2",
     "@total-typescript/ts-reset": "0.5.1",
     "bun-types": "1.1.4",
-    "eslint": "9.1.0",
+    "eslint": "9.1.1",
     "husky": "9.0.11",
     "prettier": "3.2.5",
     "tsup": "8.0.2",
@@ -39,7 +39,7 @@
     "build": "tsup src/plugin.ts --clean --dts --external graphql",
     "format": "prettier --write .",
     "format-check": "prettier --check .",
-    "integration": "bun run build && graphql-codegen && ./gradlew compileTestKotlin",
+    "integration": "bun run build && graphql-codegen && ./gradlew build",
     "lint": "eslint .",
     "prepack": "bun run build",
     "prepare": "husky",
diff --git a/src/config.ts b/src/config.ts
index 5a3a217..fa9f41b 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -15,6 +15,7 @@ import {
   array,
   boolean,
   enum_,
+  literal,
   object,
   optional,
   string,
@@ -44,11 +45,11 @@ export const configSchema = object({
   dependentTypesInScope: optional(array(string())),
   /**
    * Denotes Kotlin classes representing union types to be treated as interfaces rather than annotation classes.
-   * This should be used for types outside `dependentTypesInScope` that are not generated by the plugin.
+   * @description This should be used for types outside `dependentTypesInScope` that are not generated by the plugin. Only use when unionGeneration is set to `ANNOTATION_CLASS`.
    */
   externalUnionsAsInterfaces: optional(array(string())),
   /**
-   * Additional imports to add to the generated file.
+   * Additional imports to add to the generated file. GraphQL Kotlin annotations are always imported.
    * @example ["com.example.additional.import.*"]
    */
   extraImports: optional(array(string())),
@@ -129,4 +130,12 @@ export const configSchema = object({
       }),
     ),
   ),
+  /**
+   * Denotes the generation strategy for union types. Defaults to `MARKER_INTERFACE`.
+   * @description The `MARKER_INTERFACE` option is highly recommended, since it is more type-safe than using annotation classes.
+   * @link https://opensource.expediagroup.com/graphql-kotlin/docs/schema-generator/writing-schemas/unions/
+   */
+  unionGeneration: optional(
+    union([literal("ANNOTATION_CLASS"), literal("MARKER_INTERFACE")]),
+  ),
 });
diff --git a/src/definitions/enum.ts b/src/definitions/enum.ts
index c4e7a7b..a06e352 100644
--- a/src/definitions/enum.ts
+++ b/src/definitions/enum.ts
@@ -15,11 +15,11 @@ import { EnumTypeDefinitionNode, EnumValueDefinitionNode } from "graphql";
 import { indentMultiline } from "@graphql-codegen/visitor-plugin-common";
 import { buildAnnotations } from "../helpers/build-annotations";
 import { shouldIncludeTypeDefinition } from "../helpers/should-include-type-definition";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "../helpers/build-config-with-defaults";
 
 export function buildEnumTypeDefinition(
   node: EnumTypeDefinitionNode,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   if (!shouldIncludeTypeDefinition(node, config)) {
     return "";
@@ -46,11 +46,11 @@ ${indentMultiline(enumValues.join(",\n") + ";", 2)}
 
 function buildEnumValueDefinition(
   node: EnumValueDefinitionNode,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   const annotations = buildAnnotations({
     config,
     definitionNode: node,
   });
-  return `${annotations}${config.convert(node)}`;
+  return `${annotations}${config.convert?.(node)}`;
 }
diff --git a/src/definitions/input.ts b/src/definitions/input.ts
index 8d34a58..ddca970 100644
--- a/src/definitions/input.ts
+++ b/src/definitions/input.ts
@@ -16,12 +16,12 @@ import { shouldIncludeTypeDefinition } from "../helpers/should-include-type-defi
 import { buildTypeMetadata } from "../helpers/build-type-metadata";
 import { buildAnnotations } from "../helpers/build-annotations";
 import { indent } from "@graphql-codegen/visitor-plugin-common";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "../helpers/build-config-with-defaults";
 
 export function buildInputObjectDefinition(
   node: InputObjectTypeDefinitionNode,
   schema: GraphQLSchema,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   if (!shouldIncludeTypeDefinition(node, config)) {
     return "";
@@ -47,7 +47,6 @@ export function buildInputObjectDefinition(
 
   const annotations = buildAnnotations({
     config,
-    inputDescription: node.description?.value,
     definitionNode: node,
   });
 
diff --git a/src/definitions/interface.ts b/src/definitions/interface.ts
index 9072eb6..bf302c0 100644
--- a/src/definitions/interface.ts
+++ b/src/definitions/interface.ts
@@ -17,12 +17,12 @@ import { indent } from "@graphql-codegen/visitor-plugin-common";
 import { buildTypeMetadata } from "../helpers/build-type-metadata";
 import { shouldIncludeTypeDefinition } from "../helpers/should-include-type-definition";
 import { buildFieldDefinition } from "../helpers/build-field-definition";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "../helpers/build-config-with-defaults";
 
 export function buildInterfaceDefinition(
   node: InterfaceTypeDefinitionNode,
   schema: GraphQLSchema,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   if (!shouldIncludeTypeDefinition(node, config)) {
     return "";
diff --git a/src/definitions/object.ts b/src/definitions/object.ts
index 56885d1..29dbcb5 100644
--- a/src/definitions/object.ts
+++ b/src/definitions/object.ts
@@ -16,16 +16,19 @@ import { buildAnnotations } from "../helpers/build-annotations";
 import { indent } from "@graphql-codegen/visitor-plugin-common";
 import { buildTypeMetadata } from "../helpers/build-type-metadata";
 import { shouldIncludeTypeDefinition } from "../helpers/should-include-type-definition";
-import { getDependentInterfaceNames } from "../helpers/dependent-type-utils";
+import {
+  getDependentInterfaceNames,
+  getDependentUnionsForType,
+} from "../helpers/dependent-type-utils";
 import { isResolverType } from "../helpers/is-resolver-type";
 import { buildFieldDefinition } from "../helpers/build-field-definition";
 import { isExternalField } from "../helpers/is-external-field";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "../helpers/build-config-with-defaults";
 
 export function buildObjectTypeDefinition(
   node: ObjectTypeDefinitionNode,
   schema: GraphQLSchema,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   if (!shouldIncludeTypeDefinition(node, config)) {
     return "";
@@ -36,25 +39,30 @@ export function buildObjectTypeDefinition(
     definitionNode: node,
   });
   const name = node.name.value;
-  const interfacesToInherit = getDependentInterfaceNames(node);
+  const dependentInterfaces = getDependentInterfaceNames(node);
+  const dependentUnions = getDependentUnionsForType(schema, node);
+  const interfacesToInherit =
+    config.unionGeneration === "MARKER_INTERFACE"
+      ? dependentInterfaces.concat(dependentUnions)
+      : dependentInterfaces;
   const interfaceInheritance = `${interfacesToInherit.length ? ` : ${interfacesToInherit.join(", ")}` : ""}`;
 
   if (isResolverType(node, config)) {
     return `${annotations}@GraphQLIgnore\ninterface ${name}${interfaceInheritance} {
-${getClassMembers({ node, schema, config })}
+${getDataClassMembers({ node, schema, config })}
 }
 
 ${annotations}@GraphQLIgnore\ninterface ${name}CompletableFuture {
-${getClassMembers({ node, schema, config, completableFuture: true })}
+${getDataClassMembers({ node, schema, config, completableFuture: true })}
 }`;
   }
 
   return `${annotations}data class ${name}(
-${getClassMembers({ node, schema, config })}
+${getDataClassMembers({ node, schema, config })}
 )${interfaceInheritance}`;
 }
 
-function getClassMembers({
+function getDataClassMembers({
   node,
   schema,
   config,
@@ -62,7 +70,7 @@ function getClassMembers({
 }: {
   node: ObjectTypeDefinitionNode;
   schema: GraphQLSchema;
-  config: CodegenConfig;
+  config: CodegenConfigWithDefaults;
   completableFuture?: boolean;
 }) {
   const resolverType = isResolverType(node, config);
diff --git a/src/definitions/union.ts b/src/definitions/union.ts
index e0a98f1..d7c55f2 100644
--- a/src/definitions/union.ts
+++ b/src/definitions/union.ts
@@ -13,25 +13,33 @@ limitations under the License.
 
 import { UnionTypeDefinitionNode } from "graphql";
 import { shouldIncludeTypeDefinition } from "../helpers/should-include-type-definition";
-import { buildDirectiveAnnotations } from "../helpers/build-directive-annotations";
-import { CodegenConfig } from "../plugin";
-import { trimDescription } from "../helpers/build-annotations";
+import { CodegenConfigWithDefaults } from "../helpers/build-config-with-defaults";
+import {
+  buildAnnotations,
+  trimDescription,
+} from "../helpers/build-annotations";
 
 export function buildUnionTypeDefinition(
   node: UnionTypeDefinitionNode,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   if (!shouldIncludeTypeDefinition(node, config)) {
     return "";
   }
+  const annotations = buildAnnotations({
+    config,
+    definitionNode: node,
+  });
+  if (config.unionGeneration === "MARKER_INTERFACE") {
+    return `${annotations}interface ${node.name.value}`;
+  }
 
-  const directiveAnnotations = buildDirectiveAnnotations(node, config);
   const possibleTypes =
     node.types?.map((type) => `${type.name.value}::class`).join(", ") || "";
-  return `${directiveAnnotations}@GraphQLUnion(
+  return `${annotations}@GraphQLUnion(
     name = "${node.name.value}",
     possibleTypes = [${possibleTypes}],
-    description = "${node.description?.value ? trimDescription(node.description.value) : ""}"
+    description = "${trimDescription(node.description?.value)}"
 )
 annotation class ${node.name.value}`;
 }
diff --git a/src/helpers/add-dependent-types-to-only-types.ts b/src/helpers/add-dependent-types-to-only-types.ts
new file mode 100644
index 0000000..ab97959
--- /dev/null
+++ b/src/helpers/add-dependent-types-to-only-types.ts
@@ -0,0 +1,36 @@
+/*
+Copyright 2024 Expedia, Inc.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    https://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
+import { getDependentTypeNames } from "./get-dependent-type-names";
+import { GraphQLSchema } from "graphql";
+
+export function addDependentTypesToOnlyTypes(
+  config: CodegenConfigWithDefaults,
+  schema: GraphQLSchema,
+) {
+  if (!config.onlyTypes) {
+    throw new Error(`onlyTypes config is required to add dependent types`);
+  }
+  const onlyTypesNodes = config.onlyTypes
+    .map((typeName) => schema.getType(typeName)?.astNode)
+    .filter(Boolean);
+  const dependentTypeNames = onlyTypesNodes.flatMap((node) =>
+    getDependentTypeNames(schema, node, config),
+  );
+  const typesInScope = config.dependentTypesInScope;
+  const dependentTypesInScope = typesInScope
+    ? dependentTypeNames.filter((typeName) => typesInScope.includes(typeName))
+    : dependentTypeNames;
+  config.onlyTypes.push(...dependentTypesInScope);
+}
diff --git a/src/helpers/add-dependent-types.ts b/src/helpers/add-dependent-types.ts
deleted file mode 100644
index a5097e4..0000000
--- a/src/helpers/add-dependent-types.ts
+++ /dev/null
@@ -1,35 +0,0 @@
-/*
-Copyright 2024 Expedia, Inc.
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-    https://www.apache.org/licenses/LICENSE-2.0
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-import { CodegenConfig } from "../plugin";
-import { getDependentTypeNames } from "./get-dependent-type-names";
-import { dependentTypeIsInScope } from "./dependent-type-is-in-scope";
-import { GraphQLSchema } from "graphql";
-
-export function addDependentTypes(
-  config: CodegenConfig,
-  schema: GraphQLSchema,
-) {
-  if (config.onlyTypes && (config.includeDependentTypes ?? true)) {
-    const onlyTypesNodes = config.onlyTypes
-      .map((typeName) => schema.getType(typeName)?.astNode)
-      .filter(Boolean);
-    const dependentTypeNames = onlyTypesNodes.flatMap((node) =>
-      getDependentTypeNames(schema, node, config.dependentTypesInScope),
-    );
-    const dependentTypesInScope = dependentTypeNames.filter((typeName) =>
-      dependentTypeIsInScope(typeName, config),
-    );
-    config.onlyTypes.push(...dependentTypesInScope);
-  }
-}
diff --git a/src/helpers/build-annotations.ts b/src/helpers/build-annotations.ts
index 0a0d12b..b74d737 100644
--- a/src/helpers/build-annotations.ts
+++ b/src/helpers/build-annotations.ts
@@ -18,8 +18,9 @@ import {
   InputValueDefinitionNode,
   TypeDefinitionNode,
 } from "graphql";
+import { buildDescriptionAnnotation } from "./build-description-annotation";
 import { buildDirectiveAnnotations } from "./build-directive-annotations";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
 import { TypeMetadata } from "./build-type-metadata";
 
 export type DefinitionNode =
@@ -30,39 +31,24 @@ export type DefinitionNode =
 
 export function buildAnnotations({
   config,
-  inputDescription,
   definitionNode,
   resolvedType,
 }: {
-  config: CodegenConfig;
-  inputDescription?: string;
-  definitionNode?: DefinitionNode;
+  config: CodegenConfigWithDefaults;
+  definitionNode: DefinitionNode;
   resolvedType?: TypeMetadata;
 }) {
-  const description =
-    inputDescription ?? definitionNode?.description?.value ?? "";
-  const descriptionAnnotator = isDeprecatedDescription(
+  const description = definitionNode?.description?.value ?? "";
+  const descriptionAnnotation = buildDescriptionAnnotation(
     description,
+    definitionNode,
+    config,
     resolvedType,
-  )
-    ? "@Deprecated"
-    : "@GraphQLDescription";
-  const descriptionValue = isDeprecatedDescription(description, resolvedType)
-    ? description.replace("DEPRECATED: ", "")
-    : description;
-  const trimmedDescription = trimDescription(descriptionValue);
-  const descriptionAnnotation = description
-    ? `${descriptionAnnotator}("${trimmedDescription}")\n`
-    : "";
-
-  const directiveAnnotations = definitionNode
-    ? buildDirectiveAnnotations(
-        definitionNode,
-        config,
-        description,
-        resolvedType,
-      )
-    : "";
+  );
+  const directiveAnnotations = buildDirectiveAnnotations(
+    definitionNode,
+    config,
+  );
   const unionAnnotation = resolvedType?.unionAnnotation
     ? `@${resolvedType.unionAnnotation}\n`
     : "";
@@ -86,19 +72,10 @@ export function buildAnnotations({
   );
 }
 
-export function isDeprecatedDescription(
-  description?: string,
-  resolvedType?: TypeMetadata,
-) {
-  return (
-    description?.startsWith("DEPRECATED: ") && !resolvedType?.unionAnnotation
-  );
-}
-
-export function trimDescription(description: string) {
+export function trimDescription(description?: string) {
   return (
     description
-      .split("\n")
+      ?.split("\n")
       .map((str) => str.trim().replaceAll('"', "").replaceAll("\\", ""))
       .find((str) => str.match(/^[a-zA-Z]/)) ?? ""
   );
diff --git a/src/helpers/build-config-with-defaults.ts b/src/helpers/build-config-with-defaults.ts
new file mode 100644
index 0000000..e58fd41
--- /dev/null
+++ b/src/helpers/build-config-with-defaults.ts
@@ -0,0 +1,23 @@
+import { GraphQLKotlinCodegenConfig } from "../plugin";
+import { buildPackageNameFromPath } from "@graphql-codegen/java-common";
+import { dirname, normalize } from "path";
+
+export function buildConfigWithDefaults(
+  config: GraphQLKotlinCodegenConfig,
+  outputFile: string,
+) {
+  return {
+    packageName: buildPackageNameFromPath(dirname(normalize(outputFile))),
+    includeDependentTypes: true,
+    unionGeneration: "MARKER_INTERFACE",
+    ...config,
+    extraImports: [
+      "com.expediagroup.graphql.generator.annotations.*",
+      ...(config.extraImports ?? []),
+    ],
+  } as const;
+}
+
+export type CodegenConfigWithDefaults = ReturnType<
+  typeof buildConfigWithDefaults
+>;
diff --git a/src/helpers/build-description-annotation.ts b/src/helpers/build-description-annotation.ts
new file mode 100644
index 0000000..24129b9
--- /dev/null
+++ b/src/helpers/build-description-annotation.ts
@@ -0,0 +1,60 @@
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
+import { TypeMetadata } from "./build-type-metadata";
+import { indent } from "@graphql-codegen/visitor-plugin-common";
+import { Kind } from "graphql/index";
+import { DefinitionNode, trimDescription } from "./build-annotations";
+
+export function buildDescriptionAnnotation(
+  description: string,
+  definitionNode: DefinitionNode,
+  config: CodegenConfigWithDefaults,
+  resolvedType?: TypeMetadata,
+) {
+  const trimmedDescription = trimDescription(description);
+  const isDeprecatedDescription = trimmedDescription.startsWith(
+    deprecatedDescriptionPrefix,
+  );
+  if (isDeprecatedDescription && resolvedType?.unionAnnotation) {
+    return `@GraphQLDescription("${trimmedDescription}")\n`;
+  } else if (isDeprecatedDescription) {
+    const descriptionValue = description.replace(
+      deprecatedDescriptionPrefix,
+      "",
+    );
+    return `@Deprecated("${trimDescription(descriptionValue)}")\n`;
+  }
+
+  const deprecatedDirective = definitionNode.directives?.find(
+    (directive) => directive.name.value === "deprecated",
+  );
+  const deprecatedReasonNode = deprecatedDirective?.arguments?.find(
+    (arg) => arg.name.value === "reason",
+  )?.value;
+  const deprecatedReason =
+    deprecatedReasonNode?.kind === "StringValue"
+      ? deprecatedReasonNode.value
+      : "";
+  const trimmedDeprecatedReason = trimDescription(deprecatedReason);
+
+  if (deprecatedDirective && resolvedType?.unionAnnotation) {
+    return `@GraphQLDescription("${trimmedDeprecatedReason}")\n`;
+  } else if (deprecatedDirective) {
+    const graphqlDescription = trimmedDescription
+      ? `@GraphQLDescription("${trimmedDescription}")\n`
+      : "";
+    const deprecatedDescription = `@Deprecated("${trimmedDeprecatedReason}")\n`;
+    return `${graphqlDescription}${graphqlDescription ? indent(deprecatedDescription, 2) : deprecatedDescription}`;
+  }
+
+  if (
+    trimmedDescription &&
+    (config.unionGeneration === "MARKER_INTERFACE" ||
+      definitionNode?.kind !== Kind.UNION_TYPE_DEFINITION)
+  ) {
+    return `@GraphQLDescription("${trimmedDescription}")\n`;
+  }
+
+  return "";
+}
+
+const deprecatedDescriptionPrefix = "DEPRECATED: ";
diff --git a/src/helpers/build-directive-annotations.ts b/src/helpers/build-directive-annotations.ts
index 4c447ff..e1c3908 100644
--- a/src/helpers/build-directive-annotations.ts
+++ b/src/helpers/build-directive-annotations.ts
@@ -11,48 +11,19 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { CodegenConfig, GraphQLKotlinCodegenConfig } from "../plugin";
-import {
-  DefinitionNode,
-  isDeprecatedDescription,
-  trimDescription,
-} from "./build-annotations";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
+import { DefinitionNode } from "./build-annotations";
 import { getFederationDirectiveReplacement } from "./get-federation-directive-replacement";
-import { TypeMetadata } from "./build-type-metadata";
 import { ConstDirectiveNode } from "graphql/language";
 
 export function buildDirectiveAnnotations(
-  incomingNode: DefinitionNode,
-  config: CodegenConfig,
-  description?: string,
-  resolvedType?: TypeMetadata,
+  definitionNode: DefinitionNode,
+  config: CodegenConfigWithDefaults,
 ) {
-  const kind = incomingNode.kind;
-  const directives = incomingNode.directives ?? [];
-
+  const directives = definitionNode.directives ?? [];
   return directives
     .map((directive) => {
       const directiveName = directive.name.value;
-      if (
-        directiveName === "deprecated" &&
-        !isDeprecatedDescription(description)
-      ) {
-        const deprecatedReasonNode = directive.arguments?.find(
-          (arg) => arg.name.value === "reason",
-        )?.value;
-        const deprecatedReason =
-          deprecatedReasonNode?.kind === "StringValue"
-            ? deprecatedReasonNode.value
-            : "";
-        if (incomingNode.description?.value && resolvedType?.unionAnnotation) {
-          return "";
-        }
-        const descriptionAnnotator = resolvedType?.unionAnnotation
-          ? "@GraphQLDescription"
-          : "@Deprecated";
-        const trimmedDeprecatedReason = trimDescription(deprecatedReason);
-        return `${descriptionAnnotator}("${trimmedDeprecatedReason}")\n`;
-      }
       const federationReplacement =
         getFederationDirectiveReplacement(directive);
       if (federationReplacement) return federationReplacement + "\n";
@@ -60,7 +31,7 @@ export function buildDirectiveAnnotations(
       const directiveReplacementFromConfig = config.directiveReplacements?.find(
         ({ directive, definitionType }) =>
           directive === directiveName &&
-          (!definitionType || definitionType === kind),
+          (!definitionType || definitionType === definitionNode.kind),
       );
       if (!directiveReplacementFromConfig) return "";
       const kotlinAnnotations = buildKotlinAnnotations(
@@ -75,7 +46,7 @@ export function buildDirectiveAnnotations(
 function buildKotlinAnnotations(
   directive: ConstDirectiveNode,
   kotlinAnnotations: NonNullable<
-    GraphQLKotlinCodegenConfig["directiveReplacements"]
+    CodegenConfigWithDefaults["directiveReplacements"]
   >[number]["kotlinAnnotations"],
 ) {
   return kotlinAnnotations.map((kotlinAnnotation) => {
diff --git a/src/helpers/build-field-definition.ts b/src/helpers/build-field-definition.ts
index ee71e0f..ca7b22c 100644
--- a/src/helpers/build-field-definition.ts
+++ b/src/helpers/build-field-definition.ts
@@ -21,12 +21,12 @@ import {
 } from "graphql";
 import { isResolverType } from "./is-resolver-type";
 import { isExternalField } from "./is-external-field";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
 
 export function buildFieldDefinition(
   fieldNode: FieldDefinitionNode,
   definitionNode: ObjectTypeDefinitionNode | InterfaceTypeDefinitionNode,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
   completableFuture?: boolean,
 ) {
   const shouldUseFunction =
diff --git a/src/helpers/build-type-metadata.ts b/src/helpers/build-type-metadata.ts
index 2682774..a704738 100644
--- a/src/helpers/build-type-metadata.ts
+++ b/src/helpers/build-type-metadata.ts
@@ -13,15 +13,15 @@ limitations under the License.
 
 import {
   GraphQLSchema,
-  isScalarType,
-  isUnionType,
   Kind,
   NamedTypeNode,
   TypeNode,
+  isScalarType,
+  isUnionType,
 } from "graphql";
 import { getBaseTypeNode } from "@graphql-codegen/visitor-plugin-common";
 import { wrapTypeWithModifiers } from "@graphql-codegen/java-common";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
 
 export interface TypeMetadata {
   typeName: string;
@@ -33,7 +33,7 @@ export interface TypeMetadata {
 export function buildTypeMetadata(
   typeNode: TypeNode,
   schema: GraphQLSchema,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ): TypeMetadata {
   const innerType = getBaseTypeNode(typeNode);
   const schemaType = schema.getType(innerType.name.value);
@@ -60,6 +60,7 @@ export function buildTypeMetadata(
     };
   } else if (isUnionType(schemaType)) {
     const shouldTreatUnionAsInterface =
+      config.unionGeneration === "MARKER_INTERFACE" ||
       config.externalUnionsAsInterfaces?.includes(schemaType.name);
     return {
       ...commonMetadata,
diff --git a/src/helpers/dependent-type-is-in-scope.ts b/src/helpers/dependent-type-is-in-scope.ts
deleted file mode 100644
index ab79b03..0000000
--- a/src/helpers/dependent-type-is-in-scope.ts
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
-Copyright 2024 Expedia, Inc.
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-    https://www.apache.org/licenses/LICENSE-2.0
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-import { CodegenConfig } from "../plugin";
-
-export function dependentTypeIsInScope(
-  typeName: string,
-  config: CodegenConfig,
-) {
-  return (
-    !config.dependentTypesInScope ||
-    config.dependentTypesInScope.includes(typeName)
-  );
-}
diff --git a/src/helpers/dependent-type-utils.ts b/src/helpers/dependent-type-utils.ts
index d8d6e65..f9da022 100644
--- a/src/helpers/dependent-type-utils.ts
+++ b/src/helpers/dependent-type-utils.ts
@@ -11,19 +11,26 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { Kind, TypeDefinitionNode, TypeNode } from "graphql";
-import { CodegenConfig } from "../plugin";
+import {
+  GraphQLSchema,
+  GraphQLUnionType,
+  Kind,
+  TypeDefinitionNode,
+  TypeNode,
+} from "graphql";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
 
 export function getDependentFieldTypeNames(
   node: TypeDefinitionNode,
-  dependentTypesInScope: CodegenConfig["dependentTypesInScope"],
+  config: CodegenConfigWithDefaults,
 ) {
   return "fields" in node && node.fields
     ? node.fields
         .map((field) => getFieldTypeName(field.type))
         .filter(
           (typeName) =>
-            !dependentTypesInScope || dependentTypesInScope.includes(typeName),
+            !config.dependentTypesInScope ||
+            config.dependentTypesInScope.includes(typeName),
         )
     : [];
 }
@@ -55,3 +62,20 @@ export function getDependentUnionNames(node: TypeDefinitionNode) {
     ? node.types?.map((type) => type.name.value) ?? []
     : [];
 }
+
+export function getDependentUnionsForType(
+  schema: GraphQLSchema,
+  node: TypeDefinitionNode,
+) {
+  const typeMap = schema.getTypeMap();
+  const unions = Object.keys(typeMap)
+    .filter(
+      (type) => typeMap[type]?.astNode?.kind === Kind.UNION_TYPE_DEFINITION,
+    )
+    .map((type) => typeMap[type] as GraphQLUnionType);
+  return unions
+    .filter((union) =>
+      union.getTypes().some((type) => type.name === node.name.value),
+    )
+    .map((union) => union.name);
+}
diff --git a/src/helpers/get-dependent-type-names.ts b/src/helpers/get-dependent-type-names.ts
index f5c26a8..60d3e49 100644
--- a/src/helpers/get-dependent-type-names.ts
+++ b/src/helpers/get-dependent-type-names.ts
@@ -18,21 +18,19 @@ import {
   getDependentInterfaceNames,
   getDependentUnionNames,
 } from "./dependent-type-utils";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
 
 export function getDependentTypeNames(
   schema: GraphQLSchema,
   node: TypeDefinitionNode,
-  dependentTypesInScope: CodegenConfig["dependentTypesInScope"],
+  config: CodegenConfigWithDefaults,
 ): string[] {
-  const namedTypes = getDependentFieldTypeNames(node, dependentTypesInScope)
+  const namedTypes = getDependentFieldTypeNames(node, config)
     .concat(getDependentUnionNames(node))
     .concat(getDependentInterfaceNames(node));
   const recursivelyFoundTypes = namedTypes
     .map((typeName) => schema.getType(typeName)?.astNode)
     .filter(Boolean)
-    .flatMap((node) =>
-      getDependentTypeNames(schema, node, dependentTypesInScope),
-    );
+    .flatMap((node) => getDependentTypeNames(schema, node, config));
   return namedTypes.concat(recursivelyFoundTypes);
 }
diff --git a/src/helpers/is-resolver-type.ts b/src/helpers/is-resolver-type.ts
index a7ca626..559ed46 100644
--- a/src/helpers/is-resolver-type.ts
+++ b/src/helpers/is-resolver-type.ts
@@ -12,11 +12,11 @@ limitations under the License.
 */
 
 import { InterfaceTypeDefinitionNode, ObjectTypeDefinitionNode } from "graphql";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
 
 export function isResolverType(
   node: ObjectTypeDefinitionNode | InterfaceTypeDefinitionNode,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   return (
     node.fields?.some((fieldNode) => fieldNode.arguments?.length) ||
diff --git a/src/helpers/should-include-type-definition.ts b/src/helpers/should-include-type-definition.ts
index fecdf5b..2187d1b 100644
--- a/src/helpers/should-include-type-definition.ts
+++ b/src/helpers/should-include-type-definition.ts
@@ -12,11 +12,11 @@ limitations under the License.
 */
 
 import { TypeDefinitionNode } from "graphql";
-import { CodegenConfig } from "../plugin";
+import { CodegenConfigWithDefaults } from "./build-config-with-defaults";
 
 export function shouldIncludeTypeDefinition(
   node: TypeDefinitionNode,
-  config: CodegenConfig,
+  config: CodegenConfigWithDefaults,
 ) {
   return !config.onlyTypes || config.onlyTypes.includes(node.name.value);
 }
diff --git a/src/plugin.ts b/src/plugin.ts
index 25c62d1..09d5ceb 100644
--- a/src/plugin.ts
+++ b/src/plugin.ts
@@ -11,12 +11,10 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import { dirname, normalize } from "path";
 import {
-  getCachedDocumentNodeFromSchema,
   PluginFunction,
+  getCachedDocumentNodeFromSchema,
 } from "@graphql-codegen/plugin-helpers";
-import { buildPackageNameFromPath } from "@graphql-codegen/java-common";
 import { KotlinVisitor } from "./visitor";
 import {
   ParsedConfig,
@@ -24,15 +22,14 @@ import {
 } from "@graphql-codegen/visitor-plugin-common";
 import { Input, safeParse } from "valibot";
 import { configSchema } from "./config";
-import { addDependentTypes } from "./helpers/add-dependent-types";
+import { addDependentTypesToOnlyTypes } from "./helpers/add-dependent-types-to-only-types";
 import { visit } from "graphql";
+import { buildConfigWithDefaults } from "./helpers/build-config-with-defaults";
 
 export type GraphQLKotlinCodegenConfig = Partial<RawConfig & ParsedConfig> &
   Input<typeof configSchema>;
-export type CodegenConfig = RawConfig &
-  ParsedConfig &
-  Input<typeof configSchema>;
-export const plugin: PluginFunction<CodegenConfig> = (
+
+export const plugin: PluginFunction<GraphQLKotlinCodegenConfig> = (
   schema,
   _,
   config,
@@ -41,7 +38,6 @@ export const plugin: PluginFunction<CodegenConfig> = (
   if (!info?.outputFile) {
     throw new Error("Missing outputFile in config");
   }
-  const relevantPath = dirname(normalize(info.outputFile));
   const { issues } = safeParse(configSchema, config);
   if (issues) {
     throw new Error(
@@ -54,21 +50,26 @@ export const plugin: PluginFunction<CodegenConfig> = (
     );
   }
 
-  addDependentTypes(config, schema);
-  const visitor = new KotlinVisitor(config, schema);
+  const configWithDefaults = buildConfigWithDefaults(config, info.outputFile);
+  if (
+    configWithDefaults.onlyTypes &&
+    configWithDefaults.includeDependentTypes
+  ) {
+    addDependentTypesToOnlyTypes(configWithDefaults, schema);
+  }
+  const visitor = new KotlinVisitor(configWithDefaults, schema);
   const astNode = getCachedDocumentNodeFromSchema(schema);
   const { definitions } = visit(astNode, visitor);
-  const packageName = `package ${
-    config.packageName ?? buildPackageNameFromPath(relevantPath)
-  }\n`;
-  const defaultImports = ["com.expediagroup.graphql.generator.annotations.*"];
+  const packageName = `package ${configWithDefaults.packageName}\n`;
   const imports =
-    defaultImports
-      .concat(config.extraImports ?? [])
+    configWithDefaults.extraImports
       .map((annotation) => `import ${annotation}`)
       .join("\n") + "\n";
   const typeDefinitions = definitions
-    .filter((d: unknown) => typeof d === "string" && d.length)
+    .filter(
+      (definition: unknown) =>
+        typeof definition === "string" && definition.length,
+    )
     .join("\n\n");
 
   return [packageName, imports, typeDefinitions].join("\n") + "\n";
diff --git a/src/visitor.ts b/src/visitor.ts
index c2b57b8..52e9082 100644
--- a/src/visitor.ts
+++ b/src/visitor.ts
@@ -15,21 +15,25 @@ import { BaseVisitor, RawConfig } from "@graphql-codegen/visitor-plugin-common";
 import {
   EnumTypeDefinitionNode,
   GraphQLSchema,
-  InterfaceTypeDefinitionNode,
   InputObjectTypeDefinitionNode,
+  InterfaceTypeDefinitionNode,
   ObjectTypeDefinitionNode,
   UnionTypeDefinitionNode,
 } from "graphql";
-import { CodegenConfig } from "./plugin";
+import { CodegenConfigWithDefaults } from "./helpers/build-config-with-defaults";
 import { buildEnumTypeDefinition } from "./definitions/enum";
 import { buildInterfaceDefinition } from "./definitions/interface";
 import { buildInputObjectDefinition } from "./definitions/input";
 import { buildObjectTypeDefinition } from "./definitions/object";
 import { buildUnionTypeDefinition } from "./definitions/union";
+import { ParsedConfig } from "@graphql-codegen/visitor-plugin-common/typings/base-visitor";
 
-export class KotlinVisitor extends BaseVisitor<RawConfig, CodegenConfig> {
+export class KotlinVisitor extends BaseVisitor<
+  RawConfig,
+  ParsedConfig & CodegenConfigWithDefaults
+> {
   constructor(
-    rawConfig: CodegenConfig,
+    rawConfig: CodegenConfigWithDefaults,
     protected _schema: GraphQLSchema,
   ) {
     super(rawConfig, rawConfig);
diff --git a/test/plugin.test.ts b/test/plugin.test.ts
index 6767630..ab1d934 100644
--- a/test/plugin.test.ts
+++ b/test/plugin.test.ts
@@ -1,5 +1,5 @@
 import { buildSchema } from "graphql";
-import { CodegenConfig, plugin } from "../src/plugin";
+import { GraphQLKotlinCodegenConfig, plugin } from "../src/plugin";
 import { describe, expect, it } from "bun:test";
 import { Types } from "@graphql-codegen/plugin-helpers";
 import * as glob from "glob";
@@ -9,7 +9,7 @@ function buildUnitTest({
   config,
 }: {
   testName: string;
-  config: CodegenConfig;
+  config: GraphQLKotlinCodegenConfig;
 }) {
   it(testName, async () => {
     const filePath = `./test/unit/${testName}`;
diff --git a/test/unit/should_annotate_types_properly/expected.kt b/test/unit/should_annotate_types_properly/expected.kt
index 93ef4cf..1ad5a55 100644
--- a/test/unit/should_annotate_types_properly/expected.kt
+++ b/test/unit/should_annotate_types_properly/expected.kt
@@ -17,22 +17,15 @@ data class TypeThatShouldBeProperlyAnnotated(
     val deprecated3: String? = null,
     @Deprecated("It only takes the first one")
     val deprecated4: String? = null,
-    @UnionThatShouldBeProperlyAnnotated
-    @GraphQLDescription("DEPRECATED: It uses the GraphQLDescription annotation for union types")
-    val deprecated5: Any? = null,
-    @UnionThatShouldBeProperlyAnnotated
-    @GraphQLDescription("It uses the GraphQLDescription annotation for union types")
-    val deprecated6: Any? = null,
-    @UnionThatShouldBeProperlyAnnotated
+    @Deprecated("It uses the GraphQLDescription annotation for union types")
+    val deprecated5: UnionThatShouldBeProperlyAnnotated? = null,
+    @Deprecated("It uses the GraphQLDescription annotation for union types")
+    val deprecated6: UnionThatShouldBeProperlyAnnotated? = null,
     @GraphQLDescription("When there is a description")
-    val deprecated7: Any? = null,
+    @Deprecated("It uses the @Deprecated annotation for the reason")
+    val deprecated7: UnionThatShouldBeProperlyAnnotated? = null,
     @Deprecated("Multiline reason")
     val deprecated8: String? = null
-)
+) : UnionThatShouldBeProperlyAnnotated
 
-@GraphQLUnion(
-    name = "UnionThatShouldBeProperlyAnnotated",
-    possibleTypes = [TypeThatShouldBeProperlyAnnotated::class],
-    description = ""
-)
-annotation class UnionThatShouldBeProperlyAnnotated
+interface UnionThatShouldBeProperlyAnnotated
diff --git a/test/unit/should_annotate_types_properly/schema.graphql b/test/unit/should_annotate_types_properly/schema.graphql
index d039336..ffdde85 100644
--- a/test/unit/should_annotate_types_properly/schema.graphql
+++ b/test/unit/should_annotate_types_properly/schema.graphql
@@ -26,7 +26,7 @@ type TypeThatShouldBeProperlyAnnotated {
     )
   "When there is a description"
   deprecated7: UnionThatShouldBeProperlyAnnotated
-    @deprecated(reason: "It omits the @Deprecated annotation for now")
+    @deprecated(reason: "It uses the @Deprecated annotation for the reason")
   deprecated8: String
     @deprecated(
       reason: "\n        Multiline reason\n        with spaces\n        "
diff --git a/test/unit/should_generate_input_types_properly/expected.kt b/test/unit/should_generate_input_types_properly/expected.kt
index f5bb75c..ac9316d 100644
--- a/test/unit/should_generate_input_types_properly/expected.kt
+++ b/test/unit/should_generate_input_types_properly/expected.kt
@@ -4,8 +4,7 @@ import com.expediagroup.graphql.generator.annotations.*
 
 @GraphQLDescription("A description for MyInputType")
 data class InputTypeThatShouldBeGeneratedProperly(
-    val username: String? = null,
-    @GraphQLDescription("A description for email")
-    val email: String? = null,
-    val name: String? = null
+    val field1: String? = null,
+    @GraphQLDescription("A description for field2")
+    val field2: String? = null
 )
diff --git a/test/unit/should_generate_input_types_properly/schema.graphql b/test/unit/should_generate_input_types_properly/schema.graphql
index 0072b3e..996f362 100644
--- a/test/unit/should_generate_input_types_properly/schema.graphql
+++ b/test/unit/should_generate_input_types_properly/schema.graphql
@@ -1,7 +1,6 @@
 "A description for MyInputType"
 input InputTypeThatShouldBeGeneratedProperly {
-  username: String
-  "A description for email"
-  email: String
-  name: String
+  field1: String
+  "A description for field2"
+  field2: String
 }
diff --git a/test/unit/should_generate_multi-union_types_properly/expected.kt b/test/unit/should_generate_multi-union_types_properly/expected.kt
index a84a223..f5bd4a8 100644
--- a/test/unit/should_generate_multi-union_types_properly/expected.kt
+++ b/test/unit/should_generate_multi-union_types_properly/expected.kt
@@ -4,29 +4,17 @@ import com.expediagroup.graphql.generator.annotations.*
 
 data class MyType3(
     val field: String? = null
-)
+) : MyUnion1, MyUnion2
 
 data class MyType4(
     val field: String? = null
-)
+) : MyUnion1, MyUnion2
 
-@GraphQLUnion(
-    name = "MyUnion1",
-    possibleTypes = [MyType3::class, MyType4::class],
-    description = ""
-)
-annotation class MyUnion1
+interface MyUnion1
 
-@GraphQLUnion(
-    name = "MyUnion2",
-    possibleTypes = [MyType3::class, MyType4::class],
-    description = ""
-)
-annotation class MyUnion2
+interface MyUnion2
 
 data class MyMultiUnionType(
-    @MyUnion1
-    val field: Any? = null,
-    @MyUnion2
-    val field2: Any? = null
+    val field: MyUnion1? = null,
+    val field2: MyUnion2? = null
 )
diff --git a/test/unit/should_generate_non-nullable_union_list_types_properly/expected.kt b/test/unit/should_generate_non-nullable_union_list_types_properly/expected.kt
index 3cf852b..aa7142b 100644
--- a/test/unit/should_generate_non-nullable_union_list_types_properly/expected.kt
+++ b/test/unit/should_generate_non-nullable_union_list_types_properly/expected.kt
@@ -5,22 +5,16 @@ import com.expediagroup.graphql.generator.annotations.*
 @GraphQLDescription("A description for MyType1")
 data class TypeForNonNullableUnionList1(
     val field: String? = null
-)
+) : UnionForNonNullableList
 
 data class TypeForNonNullableUnionList2(
     val field: String? = null
-)
+) : UnionForNonNullableList
 
-@GraphQLUnion(
-    name = "UnionForNonNullableList",
-    possibleTypes = [TypeForNonNullableUnionList1::class, TypeForNonNullableUnionList2::class],
-    description = "A description for UnionForNonNullableList"
-)
-annotation class UnionForNonNullableList
+@GraphQLDescription("A description for UnionForNonNullableList")
+interface UnionForNonNullableList
 
 data class MyNonNullableUnionListType(
-    @UnionForNonNullableList
-    val field: List<Any> = emptyList(),
-    @UnionForNonNullableList
-    val field2: List<Any?> = emptyList()
+    val field: List<UnionForNonNullableList> = emptyList(),
+    val field2: List<UnionForNonNullableList?> = emptyList()
 )
diff --git a/test/unit/should_generate_union_list_types_properly/expected.kt b/test/unit/should_generate_union_list_types_properly/expected.kt
index 1777385..d35f292 100644
--- a/test/unit/should_generate_union_list_types_properly/expected.kt
+++ b/test/unit/should_generate_union_list_types_properly/expected.kt
@@ -5,23 +5,17 @@ import com.expediagroup.graphql.generator.annotations.*
 @GraphQLDescription("A description for TypeForGeneratingUnionListTypes1")
 data class TypeForGeneratingUnionListTypes1(
     val field: String? = null
-)
+) : UnionForGeneratingUnionListTypes
 
 data class TypeForGeneratingUnionListTypes2(
     val field: String? = null
-)
+) : UnionForGeneratingUnionListTypes
 
-@GraphQLUnion(
-    name = "UnionForGeneratingUnionListTypes",
-    possibleTypes = [TypeForGeneratingUnionListTypes1::class, TypeForGeneratingUnionListTypes2::class],
-    description = "A description for UnionForGeneratingUnionListTypes"
-)
-annotation class UnionForGeneratingUnionListTypes
+@GraphQLDescription("A description for UnionForGeneratingUnionListTypes")
+interface UnionForGeneratingUnionListTypes
 
 data class MyUnionListType(
-    @UnionForGeneratingUnionListTypes
     @GraphQLDescription("A description for field")
-    val field: List<Any>? = null,
-    @UnionForGeneratingUnionListTypes
-    val field2: List<Any?>? = null
+    val field: List<UnionForGeneratingUnionListTypes>? = null,
+    val field2: List<UnionForGeneratingUnionListTypes?>? = null
 )
diff --git a/test/unit/should_generate_union_types_properly/expected.kt b/test/unit/should_generate_union_types_properly/expected.kt
index 229f757..a06a063 100644
--- a/test/unit/should_generate_union_types_properly/expected.kt
+++ b/test/unit/should_generate_union_types_properly/expected.kt
@@ -5,22 +5,17 @@ import com.expediagroup.graphql.generator.annotations.*
 @GraphQLDescription("A description for MyType1")
 data class TypeForGeneratingUnionTypesProperly1(
     val field: String? = null
-)
+) : UnionForGeneratingUnionsProperly
 
 data class TypeForGeneratingUnionTypesProperly2(
     val field: String? = null
-)
+) : UnionForGeneratingUnionsProperly
 
-@GraphQLUnion(
-    name = "UnionForGeneratingUnionsProperly",
-    possibleTypes = [TypeForGeneratingUnionTypesProperly1::class, TypeForGeneratingUnionTypesProperly2::class],
-    description = "A trimmed description for UnionForGeneratingUnionsProperly"
-)
-annotation class UnionForGeneratingUnionsProperly
+@GraphQLDescription("A trimmed description for UnionForGeneratingUnionsProperly")
+interface UnionForGeneratingUnionsProperly
 
 data class MyUnionType(
-    @UnionForGeneratingUnionsProperly
     @GraphQLDescription("A description for field")
-    val field: Any? = null,
+    val field: UnionForGeneratingUnionsProperly? = null,
     val field2: String? = null
 )
diff --git a/test/unit/should_honor_dependentTypesInScope_config/expected.kt b/test/unit/should_honor_dependentTypesInScope_config/expected.kt
index 6096c18..e7ea92e 100644
--- a/test/unit/should_honor_dependentTypesInScope_config/expected.kt
+++ b/test/unit/should_honor_dependentTypesInScope_config/expected.kt
@@ -10,20 +10,13 @@ data class MyTypeInOnlyTypes(
 
 data class TypeInScope(
     val field: String? = null,
-    @UnionInScope
-    val unionInScopeField: Any? = null,
-    @UnionOutOfScope
-    val unionOutOfScopeField: Any? = null,
+    val unionInScopeField: UnionInScope? = null,
+    val unionOutOfScopeField: UnionOutOfScope? = null,
     val externalUnionAsInterfaceField: ExternalUnionAsInterface? = null
 )
 
-@GraphQLUnion(
-    name = "UnionInScope",
-    possibleTypes = [Type1::class],
-    description = ""
-)
-annotation class UnionInScope
+interface UnionInScope
 
 data class Type1(
     val field: String? = null
-)
+) : UnionInScope, ExternalUnionAsInterface
diff --git a/test/unit/should_honor_dependentTypesInScope_config/externalClasses.kt b/test/unit/should_honor_dependentTypesInScope_config/externalClasses.kt
index cd9d127..92abfe7 100644
--- a/test/unit/should_honor_dependentTypesInScope_config/externalClasses.kt
+++ b/test/unit/should_honor_dependentTypesInScope_config/externalClasses.kt
@@ -4,4 +4,4 @@ data class TypeOutOfScope(val value: String)
 
 interface ExternalUnionAsInterface
 
-annotation class UnionOutOfScope
+interface UnionOutOfScope
diff --git a/test/unit/should_honor_directiveReplacements_config/expected.kt b/test/unit/should_honor_directiveReplacements_config/expected.kt
index 08dd3dc..b353397 100644
--- a/test/unit/should_honor_directiveReplacements_config/expected.kt
+++ b/test/unit/should_honor_directiveReplacements_config/expected.kt
@@ -9,13 +9,9 @@ import should_honor_directiveReplacements_config.*
 @SomeAnnotationWithArgs(arg1 = "arg1", arg2 = 0)
 data class TypeHonoringDirectiveReplacements(
     val field: String? = null
-)
+) : MyDirectiveUnion
 
+@GraphQLDescription("A description for MyDirectiveUnion")
 @SomeAnnotation1
 @SomeAnnotation2
-@GraphQLUnion(
-    name = "MyDirectiveUnion",
-    possibleTypes = [TypeHonoringDirectiveReplacements::class],
-    description = "A description for MyDirectiveUnion"
-)
-annotation class MyDirectiveUnion
+interface MyDirectiveUnion
diff --git a/test/unit/should_honor_onlyTypes_config/expected.kt b/test/unit/should_honor_onlyTypes_config/expected.kt
index 9bea03e..6997a70 100644
--- a/test/unit/should_honor_onlyTypes_config/expected.kt
+++ b/test/unit/should_honor_onlyTypes_config/expected.kt
@@ -3,11 +3,11 @@ package com.kotlin.generated
 import com.expediagroup.graphql.generator.annotations.*
 
 data class TypeHonoringOnlyTypesConfig(
-    val username: String? = null,
-    @GraphQLDescription("A description for email")
-    val email: String? = null,
+    val field1: String? = null,
+    @GraphQLDescription("A description for field2")
+    val field2: String? = null,
     @GraphQLDescription("A `weird` description for name")
-    val name: String? = null
+    val field3: String? = null
 )
 
 @GraphQLDescription("A description for MyEnum")
diff --git a/test/unit/should_honor_onlyTypes_config/schema.graphql b/test/unit/should_honor_onlyTypes_config/schema.graphql
index e21a829..4ae6837 100644
--- a/test/unit/should_honor_onlyTypes_config/schema.graphql
+++ b/test/unit/should_honor_onlyTypes_config/schema.graphql
@@ -1,11 +1,11 @@
 type TypeHonoringOnlyTypesConfig {
-  username: String
-  "A description for email"
-  email: String
+  field1: String
+  "A description for field2"
+  field2: String
   """
   A \`weird\` description for name
   """
-  name: String
+  field3: String
 }
 
 "A description for MyEnum"
diff --git a/test/unit/should_honor_union_generation_config/codegen.config.ts b/test/unit/should_honor_union_generation_config/codegen.config.ts
new file mode 100644
index 0000000..8b31606
--- /dev/null
+++ b/test/unit/should_honor_union_generation_config/codegen.config.ts
@@ -0,0 +1,5 @@
+import { GraphQLKotlinCodegenConfig } from "../../../src/plugin";
+
+export default {
+  unionGeneration: "ANNOTATION_CLASS",
+} satisfies GraphQLKotlinCodegenConfig;
diff --git a/test/unit/should_honor_union_generation_config/expected.kt b/test/unit/should_honor_union_generation_config/expected.kt
new file mode 100644
index 0000000..faab3b8
--- /dev/null
+++ b/test/unit/should_honor_union_generation_config/expected.kt
@@ -0,0 +1,37 @@
+package com.kotlin.generated
+
+import com.expediagroup.graphql.generator.annotations.*
+
+@GraphQLDescription("A description for TypeForHonoringUnionGenerationConfig1")
+data class TypeForHonoringUnionGenerationConfig1(
+    val field: String? = null
+)
+
+data class TypeForHonoringUnionGenerationConfig2(
+    val field: String? = null
+)
+
+@GraphQLUnion(
+    name = "UnionAsAnnotation",
+    possibleTypes = [TypeForHonoringUnionGenerationConfig1::class, TypeForHonoringUnionGenerationConfig2::class],
+    description = "A description for UnionAsAnnotation"
+)
+annotation class UnionAsAnnotation
+
+data class UnionForHonoringUnionGenerationConfig(
+    @UnionAsAnnotation
+    @GraphQLDescription("A description for field")
+    val field: Any? = null,
+    @UnionAsAnnotation
+    @GraphQLDescription("DEPRECATED: It uses the GraphQLDescription annotation for union annotations")
+    val deprecated1: Any? = null,
+    @UnionAsAnnotation
+    @GraphQLDescription("DEPRECATED: It uses the GraphQLDescription annotation for union types")
+    val deprecated2: Any? = null,
+    @UnionAsAnnotation
+    @GraphQLDescription("It uses the GraphQLDescription annotation for union types")
+    val deprecated3: Any? = null,
+    @UnionAsAnnotation
+    @GraphQLDescription("It omits the @Deprecated annotation for now")
+    val deprecated4: Any? = null
+)
diff --git a/test/unit/should_honor_union_generation_config/schema.graphql b/test/unit/should_honor_union_generation_config/schema.graphql
new file mode 100644
index 0000000..8756c26
--- /dev/null
+++ b/test/unit/should_honor_union_generation_config/schema.graphql
@@ -0,0 +1,32 @@
+"A description for TypeForHonoringUnionGenerationConfig1"
+type TypeForHonoringUnionGenerationConfig1 {
+  field: String
+}
+
+type TypeForHonoringUnionGenerationConfig2 {
+  field: String
+}
+
+"""
+A description for UnionAsAnnotation
+"""
+union UnionAsAnnotation =
+  | TypeForHonoringUnionGenerationConfig1
+  | TypeForHonoringUnionGenerationConfig2
+
+type UnionForHonoringUnionGenerationConfig {
+  "A description for field"
+  field: UnionAsAnnotation
+  "DEPRECATED: It uses the GraphQLDescription annotation for union annotations"
+  deprecated1: UnionAsAnnotation
+    @deprecated(reason: "when you have multiple deprecated annotations")
+  "DEPRECATED: It uses the GraphQLDescription annotation for union types"
+  deprecated2: UnionAsAnnotation
+  deprecated3: UnionAsAnnotation
+    @deprecated(
+      reason: "It uses the GraphQLDescription annotation for union types"
+    )
+  "When there is a description"
+  deprecated4: UnionAsAnnotation
+    @deprecated(reason: "It omits the @Deprecated annotation for now")
+}
diff --git a/test/unit/should_include_dependent_types_in_onlyTypes_config/expected.kt b/test/unit/should_include_dependent_types_in_onlyTypes_config/expected.kt
index 05c4797..1895564 100644
--- a/test/unit/should_include_dependent_types_in_onlyTypes_config/expected.kt
+++ b/test/unit/should_include_dependent_types_in_onlyTypes_config/expected.kt
@@ -6,8 +6,7 @@ data class MyType(
     val typeField: MyNestedType,
     val typeListField: List<ListType> = emptyList(),
     val enumField: MyEnum,
-    @MyUnion
-    val unionField: Any,
+    val unionField: MyUnion,
     val unionImplementationField: UnionImplementation,
     val interfaceField: MyInterface1,
     val interfaceImplementationField: MyImplementedInterface
@@ -34,24 +33,19 @@ enum class MyEnum {
     }
 }
 
-@GraphQLUnion(
-    name = "MyUnion",
-    possibleTypes = [MyType1::class, MyType2::class],
-    description = ""
-)
-annotation class MyUnion
+interface MyUnion
 
 data class MyType1(
     val field: String? = null
-)
+) : MyUnion
 
 data class MyType2(
     val field: String? = null
-)
+) : MyUnion
 
 data class UnionImplementation(
     val field: String? = null
-)
+) : MyUnion2
 
 interface MyInterface1 {
     val field: String?
@@ -73,16 +67,11 @@ data class MyNestedInput(
     val field: String? = null
 )
 
-@GraphQLUnion(
-    name = "MyStandaloneUnion",
-    possibleTypes = [StandaloneUnionType::class],
-    description = ""
-)
-annotation class MyStandaloneUnion
+interface MyStandaloneUnion
 
 data class StandaloneUnionType(
     val field: StandaloneNestedType? = null
-)
+) : MyStandaloneUnion
 
 data class StandaloneNestedType(
     val field: String? = null