diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinMiskServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinMiskServerCodegen.java
index ccdbbd6da93f..f873d7061362 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinMiskServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/KotlinMiskServerCodegen.java
@@ -172,6 +172,8 @@ public KotlinMiskServerCodegen() {
         artifactId = "openapi-kotlin-misk-server";
         artifactVersion = apiVersion;
 
+        typeMapping.put("array", "kotlin.collections.List");
+
         updateOption(CodegenConstants.API_PACKAGE, apiPackage);
         updateOption(CodegenConstants.MODEL_PACKAGE, modelPackage);
         additionalProperties.put(ROOT_PACKAGE, rootPackage);
@@ -328,4 +330,4 @@ private static Map<String, String> getMappings() {
 
         return result;
     }
-}
+}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/kotlin-misk/apiAction.mustache b/modules/openapi-generator/src/main/resources/kotlin-misk/apiAction.mustache
index 094e78f60b54..9d9f929aeed6 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-misk/apiAction.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-misk/apiAction.mustache
@@ -28,6 +28,7 @@ import misk.web.QueryParam
 import misk.web.RequestBody
 import misk.web.RequestContentType
 import misk.web.RequestHeader
+import misk.web.Response
 import misk.web.ResponseContentType
 import misk.web.mediatype.MediaTypes
 {{#imports}}
@@ -50,10 +51,13 @@ class {{classname}}Action @Inject constructor(
 {{#actionAnnotations}}
     {{{.}}}
 {{/actionAnnotations}}
-    fun {{operationId}}({{#allParams}}
-        {{>queryParams}}{{>pathParams}}{{>headerParams}}{{>cookieParams}}{{>bodyParams}}{{>formParams}}{{^-last}}, {{/-last}}{{/allParams}}){{#returnType}}: {{{returnType}}}{{/returnType}} {
+    fun {{operationId}}(
+{{#allParams}}
+        {{>queryParams}}{{>pathParams}}{{>headerParams}}{{>cookieParams}}{{>bodyParams}}{{>formParams}}{{^-last}}, {{/-last}}
+{{/allParams}}
+    ): {{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Response<Unit>{{/returnType}} {
         TODO()
     }
 {{/operation}}
 }
-{{/operations}}
+{{/operations}}
\ No newline at end of file
diff --git a/modules/openapi-generator/src/main/resources/kotlin-misk/optionalDataType.mustache b/modules/openapi-generator/src/main/resources/kotlin-misk/optionalDataType.mustache
index 96a2ec611e60..cb39a7d46a70 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-misk/optionalDataType.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-misk/optionalDataType.mustache
@@ -1 +1 @@
-{{^isFile}}{{{dataType}}}{{^required}}{{^defaultValue}}?{{/defaultValue}}{{/required}}{{/isFile}}{{#isFile}}{{#isArray}}Array<{{/isArray}}{{#isArray}}>{{/isArray}}{{^isArray}}{{^required}}{{/required}}{{/isArray}}{{/isFile}}
\ No newline at end of file
+{{^isFile}}{{{dataType}}}{{^required}}{{^defaultValue}}?{{/defaultValue}}{{/required}}{{/isFile}}{{#isFile}}{{#isArray}}kotlin.collections.List<{{/isArray}}{{#isArray}}>{{/isArray}}{{^isArray}}{{^required}}{{/required}}{{/isArray}}{{/isFile}}
\ No newline at end of file
diff --git a/samples/server/petstore/kotlin-misk-config/docs/Pet.md b/samples/server/petstore/kotlin-misk-config/docs/Pet.md
index e60adf1fc22f..da70fca06e65 100644
--- a/samples/server/petstore/kotlin-misk-config/docs/Pet.md
+++ b/samples/server/petstore/kotlin-misk-config/docs/Pet.md
@@ -5,10 +5,10 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **name** | **kotlin.String** |  | 
-**photoUrls** | **kotlin.Array&lt;kotlin.String&gt;** |  | 
+**photoUrls** | **kotlin.collections.List&lt;kotlin.String&gt;** |  | 
 **id** | **kotlin.Long** |  |  [optional]
 **category** | [**Category**](Category.md) |  |  [optional]
-**tags** | [**kotlin.Array&lt;Tag&gt;**](Tag.md) |  |  [optional]
+**tags** | [**kotlin.collections.List&lt;Tag&gt;**](Tag.md) |  |  [optional]
 **status** | [**inline**](#Status) | pet status in the store |  [optional]
 
 
diff --git a/samples/server/petstore/kotlin-misk-config/docs/PetApi.md b/samples/server/petstore/kotlin-misk-config/docs/PetApi.md
index c12d3668388c..99dbe788edb0 100644
--- a/samples/server/petstore/kotlin-misk-config/docs/PetApi.md
+++ b/samples/server/petstore/kotlin-misk-config/docs/PetApi.md
@@ -111,7 +111,7 @@ null (empty response body)
 
 <a name="findPetsByStatus"></a>
 # **findPetsByStatus**
-> kotlin.Array&lt;Pet&gt; findPetsByStatus(status)
+> kotlin.collections.List&lt;Pet&gt; findPetsByStatus(status)
 
 Finds Pets by status
 
@@ -124,9 +124,9 @@ Multiple status values can be provided with comma separated strings
 //import org.openapitools.server.api.model.*
 
 val apiInstance = PetApi()
-val status : kotlin.Array<kotlin.String> =  // kotlin.Array<kotlin.String> | Status values that need to be considered for filter
+val status : kotlin.collections.List<kotlin.String> =  // kotlin.collections.List<kotlin.String> | Status values that need to be considered for filter
 try {
-    val result : kotlin.Array<Pet> = apiInstance.findPetsByStatus(status)
+    val result : kotlin.collections.List<Pet> = apiInstance.findPetsByStatus(status)
     println(result)
 } catch (e: ClientException) {
     println("4xx response calling PetApi#findPetsByStatus")
@@ -141,11 +141,11 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **status** | [**kotlin.Array&lt;kotlin.String&gt;**](kotlin.String.md)| Status values that need to be considered for filter | [enum: available, pending, sold]
+ **status** | [**kotlin.collections.List&lt;kotlin.String&gt;**](kotlin.String.md)| Status values that need to be considered for filter | [enum: available, pending, sold]
 
 ### Return type
 
-[**kotlin.Array&lt;Pet&gt;**](Pet.md)
+[**kotlin.collections.List&lt;Pet&gt;**](Pet.md)
 
 ### Authorization
 
@@ -158,7 +158,7 @@ Name | Type | Description  | Notes
 
 <a name="findPetsByTags"></a>
 # **findPetsByTags**
-> kotlin.Array&lt;Pet&gt; findPetsByTags(tags)
+> kotlin.collections.List&lt;Pet&gt; findPetsByTags(tags)
 
 Finds Pets by tags
 
@@ -171,9 +171,9 @@ Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3
 //import org.openapitools.server.api.model.*
 
 val apiInstance = PetApi()
-val tags : kotlin.Array<kotlin.String> =  // kotlin.Array<kotlin.String> | Tags to filter by
+val tags : kotlin.collections.List<kotlin.String> =  // kotlin.collections.List<kotlin.String> | Tags to filter by
 try {
-    val result : kotlin.Array<Pet> = apiInstance.findPetsByTags(tags)
+    val result : kotlin.collections.List<Pet> = apiInstance.findPetsByTags(tags)
     println(result)
 } catch (e: ClientException) {
     println("4xx response calling PetApi#findPetsByTags")
@@ -188,11 +188,11 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **tags** | [**kotlin.Array&lt;kotlin.String&gt;**](kotlin.String.md)| Tags to filter by |
+ **tags** | [**kotlin.collections.List&lt;kotlin.String&gt;**](kotlin.String.md)| Tags to filter by |
 
 ### Return type
 
-[**kotlin.Array&lt;Pet&gt;**](Pet.md)
+[**kotlin.collections.List&lt;Pet&gt;**](Pet.md)
 
 ### Authorization
 
diff --git a/samples/server/petstore/kotlin-misk-config/docs/UserApi.md b/samples/server/petstore/kotlin-misk-config/docs/UserApi.md
index b8f5fca6eea0..ef066d94e9f9 100644
--- a/samples/server/petstore/kotlin-misk-config/docs/UserApi.md
+++ b/samples/server/petstore/kotlin-misk-config/docs/UserApi.md
@@ -75,7 +75,7 @@ Creates list of users with given input array
 //import org.openapitools.server.api.model.*
 
 val apiInstance = UserApi()
-val user : kotlin.Array<User> =  // kotlin.Array<User> | List of user object
+val user : kotlin.collections.List<User> =  // kotlin.collections.List<User> | List of user object
 try {
     apiInstance.createUsersWithArrayInput(user)
 } catch (e: ClientException) {
@@ -91,7 +91,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **user** | [**kotlin.Array&lt;User&gt;**](User.md)| List of user object |
+ **user** | [**kotlin.collections.List&lt;User&gt;**](User.md)| List of user object |
 
 ### Return type
 
@@ -121,7 +121,7 @@ Creates list of users with given input array
 //import org.openapitools.server.api.model.*
 
 val apiInstance = UserApi()
-val user : kotlin.Array<User> =  // kotlin.Array<User> | List of user object
+val user : kotlin.collections.List<User> =  // kotlin.collections.List<User> | List of user object
 try {
     apiInstance.createUsersWithListInput(user)
 } catch (e: ClientException) {
@@ -137,7 +137,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **user** | [**kotlin.Array&lt;User&gt;**](User.md)| List of user object |
+ **user** | [**kotlin.collections.List&lt;User&gt;**](User.md)| List of user object |
 
 ### Return type
 
diff --git a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt
index f8784b0c7715..f98d5a463e85 100644
--- a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt
+++ b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt
@@ -25,6 +25,7 @@ import misk.web.QueryParam
 import misk.web.RequestBody
 import misk.web.RequestContentType
 import misk.web.RequestHeader
+import misk.web.Response
 import misk.web.ResponseContentType
 import misk.web.mediatype.MediaTypes
 import org.openapitools.server.api.model.ModelApiResponse
@@ -44,7 +45,8 @@ class PetApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun addPet(
-        @Valid @RequestBody pet: Pet): Pet {
+        @Valid @RequestBody pet: Pet
+    ): Pet {
         TODO()
     }
 
@@ -54,7 +56,8 @@ class PetApiAction @Inject constructor(
     @Suppress("unused")
     fun deletePet(
         @PathParam("petId") petId: kotlin.Long, 
-        @RequestHeader(value = "api_key") apiKey: kotlin.String?) {
+        @RequestHeader(value = "api_key") apiKey: kotlin.String?
+    ): Response<Unit> {
         TODO()
     }
 
@@ -64,7 +67,8 @@ class PetApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun findPetsByStatus(
-         @QueryParam(value = "status") status: kotlin.Array<kotlin.String>): kotlin.Array<Pet> {
+         @QueryParam(value = "status") status: kotlin.collections.List<kotlin.String>
+    ): kotlin.collections.List<Pet> {
         TODO()
     }
 
@@ -74,7 +78,8 @@ class PetApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun findPetsByTags(
-         @QueryParam(value = "tags") tags: kotlin.Array<kotlin.String>): kotlin.Array<Pet> {
+         @QueryParam(value = "tags") tags: kotlin.collections.List<kotlin.String>
+    ): kotlin.collections.List<Pet> {
         TODO()
     }
 
@@ -84,7 +89,8 @@ class PetApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun getPetById(
-        @PathParam("petId") petId: kotlin.Long): Pet {
+        @PathParam("petId") petId: kotlin.Long
+    ): Pet {
         TODO()
     }
 
@@ -95,7 +101,8 @@ class PetApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun updatePet(
-        @Valid @RequestBody pet: Pet): Pet {
+        @Valid @RequestBody pet: Pet
+    ): Pet {
         TODO()
     }
 
@@ -107,7 +114,8 @@ class PetApiAction @Inject constructor(
     fun updatePetWithForm(
         @PathParam("petId") petId: kotlin.Long, 
         @QueryParam(value = "name") name: kotlin.String? , 
-        @QueryParam(value = "status") status: kotlin.String? ) {
+        @QueryParam(value = "status") status: kotlin.String? 
+    ): Response<Unit> {
         TODO()
     }
 
@@ -120,7 +128,8 @@ class PetApiAction @Inject constructor(
     fun uploadFile(
         @PathParam("petId") petId: kotlin.Long, 
         @QueryParam(value = "additionalMetadata") additionalMetadata: kotlin.String? , 
-        @Valid file: HttpCall): ModelApiResponse {
+        @Valid file: HttpCall
+    ): ModelApiResponse {
         TODO()
     }
 }
diff --git a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt
index 55912b1754f1..a9a09ac45943 100644
--- a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt
+++ b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt
@@ -25,6 +25,7 @@ import misk.web.QueryParam
 import misk.web.RequestBody
 import misk.web.RequestContentType
 import misk.web.RequestHeader
+import misk.web.Response
 import misk.web.ResponseContentType
 import misk.web.mediatype.MediaTypes
 import org.openapitools.server.api.model.Order
@@ -41,7 +42,8 @@ class StoreApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun deleteOrder(
-        @PathParam("orderId") orderId: kotlin.String) {
+        @PathParam("orderId") orderId: kotlin.String
+    ): Response<Unit> {
         TODO()
     }
 
@@ -50,7 +52,8 @@ class StoreApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
-    fun getInventory(): kotlin.collections.Map<kotlin.String, kotlin.Int> {
+    fun getInventory(
+    ): kotlin.collections.Map<kotlin.String, kotlin.Int> {
         TODO()
     }
 
@@ -60,7 +63,8 @@ class StoreApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun getOrderById(
-        @Min(1L) @Max(5L) @PathParam("orderId") orderId: kotlin.Long): Order {
+        @Min(1L) @Max(5L) @PathParam("orderId") orderId: kotlin.Long
+    ): Order {
         TODO()
     }
 
@@ -71,7 +75,8 @@ class StoreApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun placeOrder(
-        @Valid @RequestBody order: Order): Order {
+        @Valid @RequestBody order: Order
+    ): Order {
         TODO()
     }
 }
diff --git a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt
index cc3fe5a0fa5c..5e7ceedae24c 100644
--- a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt
+++ b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt
@@ -25,6 +25,7 @@ import misk.web.QueryParam
 import misk.web.RequestBody
 import misk.web.RequestContentType
 import misk.web.RequestHeader
+import misk.web.Response
 import misk.web.ResponseContentType
 import misk.web.mediatype.MediaTypes
 import org.openapitools.server.api.model.User
@@ -42,7 +43,8 @@ class UserApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun createUser(
-        @Valid @RequestBody user: User) {
+        @Valid @RequestBody user: User
+    ): Response<Unit> {
         TODO()
     }
 
@@ -52,7 +54,8 @@ class UserApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun createUsersWithArrayInput(
-        @Valid @RequestBody user: kotlin.Array<User>) {
+        @Valid @RequestBody user: kotlin.collections.List<User>
+    ): Response<Unit> {
         TODO()
     }
 
@@ -62,7 +65,8 @@ class UserApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun createUsersWithListInput(
-        @Valid @RequestBody user: kotlin.Array<User>) {
+        @Valid @RequestBody user: kotlin.collections.List<User>
+    ): Response<Unit> {
         TODO()
     }
 
@@ -71,7 +75,8 @@ class UserApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun deleteUser(
-        @PathParam("username") username: kotlin.String) {
+        @PathParam("username") username: kotlin.String
+    ): Response<Unit> {
         TODO()
     }
 
@@ -81,7 +86,8 @@ class UserApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
     fun getUserByName(
-        @PathParam("username") username: kotlin.String): User {
+        @PathParam("username") username: kotlin.String
+    ): User {
         TODO()
     }
 
@@ -92,7 +98,8 @@ class UserApiAction @Inject constructor(
     @Suppress("unused")
     fun loginUser(
          @QueryParam(value = "username") username: kotlin.String, 
-         @QueryParam(value = "password") password: kotlin.String): kotlin.String {
+         @QueryParam(value = "password") password: kotlin.String
+    ): kotlin.String {
         TODO()
     }
 
@@ -100,7 +107,8 @@ class UserApiAction @Inject constructor(
     @Description("Logs out current logged in user session")
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 2.0)
     @Suppress("unused")
-    fun logoutUser() {
+    fun logoutUser(
+    ): Response<Unit> {
         TODO()
     }
 
@@ -111,7 +119,8 @@ class UserApiAction @Inject constructor(
     @Suppress("unused")
     fun updateUser(
         @PathParam("username") username: kotlin.String, 
-        @Valid @RequestBody user: User) {
+        @Valid @RequestBody user: User
+    ): Response<Unit> {
         TODO()
     }
 }
diff --git a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/model/Pet.kt b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/model/Pet.kt
index 0011e60785e4..a48be4bbf406 100644
--- a/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/model/Pet.kt
+++ b/samples/server/petstore/kotlin-misk-config/src/main/kotlin/org/openapitools/server/api/model/Pet.kt
@@ -7,10 +7,10 @@ import com.squareup.moshi.JsonClass
 @JsonClass(generateAdapter = true)
 data class Pet(
     val name: kotlin.String,
-    val photoUrls: kotlin.Array<kotlin.String>,
+    val photoUrls: kotlin.collections.List<kotlin.String>,
     val id: kotlin.Long? = null,
     val category: Category? = null,
-    val tags: kotlin.Array<Tag>? = null,
+    val tags: kotlin.collections.List<Tag>? = null,
     /** pet status in the store */
     val status: kotlin.String? = null
 )
diff --git a/samples/server/petstore/kotlin-misk-config/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt b/samples/server/petstore/kotlin-misk-config/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt
index cabdd730fe75..c874c99576d7 100644
--- a/samples/server/petstore/kotlin-misk-config/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt
+++ b/samples/server/petstore/kotlin-misk-config/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt
@@ -47,7 +47,7 @@ internal class PetApiTest {
     @Test
     fun `should handle findPetsByStatus`() {
         val status = TODO()
-        val response: kotlin.Array<Pet> = petApi.findPetsByStatus(status)
+        val response: kotlin.collections.List<Pet> = petApi.findPetsByStatus(status)
     }
 
     /**
@@ -56,7 +56,7 @@ internal class PetApiTest {
     @Test
     fun `should handle findPetsByTags`() {
         val tags = TODO()
-        val response: kotlin.Array<Pet> = petApi.findPetsByTags(tags)
+        val response: kotlin.collections.List<Pet> = petApi.findPetsByTags(tags)
     }
 
     /**
diff --git a/samples/server/petstore/kotlin-misk/docs/Pet.md b/samples/server/petstore/kotlin-misk/docs/Pet.md
index e60adf1fc22f..da70fca06e65 100644
--- a/samples/server/petstore/kotlin-misk/docs/Pet.md
+++ b/samples/server/petstore/kotlin-misk/docs/Pet.md
@@ -5,10 +5,10 @@
 Name | Type | Description | Notes
 ------------ | ------------- | ------------- | -------------
 **name** | **kotlin.String** |  | 
-**photoUrls** | **kotlin.Array&lt;kotlin.String&gt;** |  | 
+**photoUrls** | **kotlin.collections.List&lt;kotlin.String&gt;** |  | 
 **id** | **kotlin.Long** |  |  [optional]
 **category** | [**Category**](Category.md) |  |  [optional]
-**tags** | [**kotlin.Array&lt;Tag&gt;**](Tag.md) |  |  [optional]
+**tags** | [**kotlin.collections.List&lt;Tag&gt;**](Tag.md) |  |  [optional]
 **status** | [**inline**](#Status) | pet status in the store |  [optional]
 
 
diff --git a/samples/server/petstore/kotlin-misk/docs/PetApi.md b/samples/server/petstore/kotlin-misk/docs/PetApi.md
index c12d3668388c..99dbe788edb0 100644
--- a/samples/server/petstore/kotlin-misk/docs/PetApi.md
+++ b/samples/server/petstore/kotlin-misk/docs/PetApi.md
@@ -111,7 +111,7 @@ null (empty response body)
 
 <a name="findPetsByStatus"></a>
 # **findPetsByStatus**
-> kotlin.Array&lt;Pet&gt; findPetsByStatus(status)
+> kotlin.collections.List&lt;Pet&gt; findPetsByStatus(status)
 
 Finds Pets by status
 
@@ -124,9 +124,9 @@ Multiple status values can be provided with comma separated strings
 //import org.openapitools.server.api.model.*
 
 val apiInstance = PetApi()
-val status : kotlin.Array<kotlin.String> =  // kotlin.Array<kotlin.String> | Status values that need to be considered for filter
+val status : kotlin.collections.List<kotlin.String> =  // kotlin.collections.List<kotlin.String> | Status values that need to be considered for filter
 try {
-    val result : kotlin.Array<Pet> = apiInstance.findPetsByStatus(status)
+    val result : kotlin.collections.List<Pet> = apiInstance.findPetsByStatus(status)
     println(result)
 } catch (e: ClientException) {
     println("4xx response calling PetApi#findPetsByStatus")
@@ -141,11 +141,11 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **status** | [**kotlin.Array&lt;kotlin.String&gt;**](kotlin.String.md)| Status values that need to be considered for filter | [enum: available, pending, sold]
+ **status** | [**kotlin.collections.List&lt;kotlin.String&gt;**](kotlin.String.md)| Status values that need to be considered for filter | [enum: available, pending, sold]
 
 ### Return type
 
-[**kotlin.Array&lt;Pet&gt;**](Pet.md)
+[**kotlin.collections.List&lt;Pet&gt;**](Pet.md)
 
 ### Authorization
 
@@ -158,7 +158,7 @@ Name | Type | Description  | Notes
 
 <a name="findPetsByTags"></a>
 # **findPetsByTags**
-> kotlin.Array&lt;Pet&gt; findPetsByTags(tags)
+> kotlin.collections.List&lt;Pet&gt; findPetsByTags(tags)
 
 Finds Pets by tags
 
@@ -171,9 +171,9 @@ Multiple tags can be provided with comma separated strings. Use tag1, tag2, tag3
 //import org.openapitools.server.api.model.*
 
 val apiInstance = PetApi()
-val tags : kotlin.Array<kotlin.String> =  // kotlin.Array<kotlin.String> | Tags to filter by
+val tags : kotlin.collections.List<kotlin.String> =  // kotlin.collections.List<kotlin.String> | Tags to filter by
 try {
-    val result : kotlin.Array<Pet> = apiInstance.findPetsByTags(tags)
+    val result : kotlin.collections.List<Pet> = apiInstance.findPetsByTags(tags)
     println(result)
 } catch (e: ClientException) {
     println("4xx response calling PetApi#findPetsByTags")
@@ -188,11 +188,11 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **tags** | [**kotlin.Array&lt;kotlin.String&gt;**](kotlin.String.md)| Tags to filter by |
+ **tags** | [**kotlin.collections.List&lt;kotlin.String&gt;**](kotlin.String.md)| Tags to filter by |
 
 ### Return type
 
-[**kotlin.Array&lt;Pet&gt;**](Pet.md)
+[**kotlin.collections.List&lt;Pet&gt;**](Pet.md)
 
 ### Authorization
 
diff --git a/samples/server/petstore/kotlin-misk/docs/UserApi.md b/samples/server/petstore/kotlin-misk/docs/UserApi.md
index b8f5fca6eea0..ef066d94e9f9 100644
--- a/samples/server/petstore/kotlin-misk/docs/UserApi.md
+++ b/samples/server/petstore/kotlin-misk/docs/UserApi.md
@@ -75,7 +75,7 @@ Creates list of users with given input array
 //import org.openapitools.server.api.model.*
 
 val apiInstance = UserApi()
-val user : kotlin.Array<User> =  // kotlin.Array<User> | List of user object
+val user : kotlin.collections.List<User> =  // kotlin.collections.List<User> | List of user object
 try {
     apiInstance.createUsersWithArrayInput(user)
 } catch (e: ClientException) {
@@ -91,7 +91,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **user** | [**kotlin.Array&lt;User&gt;**](User.md)| List of user object |
+ **user** | [**kotlin.collections.List&lt;User&gt;**](User.md)| List of user object |
 
 ### Return type
 
@@ -121,7 +121,7 @@ Creates list of users with given input array
 //import org.openapitools.server.api.model.*
 
 val apiInstance = UserApi()
-val user : kotlin.Array<User> =  // kotlin.Array<User> | List of user object
+val user : kotlin.collections.List<User> =  // kotlin.collections.List<User> | List of user object
 try {
     apiInstance.createUsersWithListInput(user)
 } catch (e: ClientException) {
@@ -137,7 +137,7 @@ try {
 
 Name | Type | Description  | Notes
 ------------- | ------------- | ------------- | -------------
- **user** | [**kotlin.Array&lt;User&gt;**](User.md)| List of user object |
+ **user** | [**kotlin.collections.List&lt;User&gt;**](User.md)| List of user object |
 
 ### Return type
 
diff --git a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt
index 1b1b88cb2654..1a8c806566d5 100644
--- a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt
+++ b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/PetApiAction.kt
@@ -25,6 +25,7 @@ import misk.web.QueryParam
 import misk.web.RequestBody
 import misk.web.RequestContentType
 import misk.web.RequestHeader
+import misk.web.Response
 import misk.web.ResponseContentType
 import misk.web.mediatype.MediaTypes
 import org.openapitools.server.api.model.ModelApiResponse
@@ -43,7 +44,8 @@ class PetApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun addPet(
-        @Valid @RequestBody pet: Pet): Pet {
+        @Valid @RequestBody pet: Pet
+    ): Pet {
         TODO()
     }
 
@@ -52,7 +54,8 @@ class PetApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun deletePet(
         @PathParam("petId") petId: kotlin.Long, 
-        @RequestHeader(value = "api_key") apiKey: kotlin.String?) {
+        @RequestHeader(value = "api_key") apiKey: kotlin.String?
+    ): Response<Unit> {
         TODO()
     }
 
@@ -61,7 +64,8 @@ class PetApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun findPetsByStatus(
-         @QueryParam(value = "status") status: kotlin.Array<kotlin.String>): kotlin.Array<Pet> {
+         @QueryParam(value = "status") status: kotlin.collections.List<kotlin.String>
+    ): kotlin.collections.List<Pet> {
         TODO()
     }
 
@@ -70,7 +74,8 @@ class PetApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun findPetsByTags(
-         @QueryParam(value = "tags") tags: kotlin.Array<kotlin.String>): kotlin.Array<Pet> {
+         @QueryParam(value = "tags") tags: kotlin.collections.List<kotlin.String>
+    ): kotlin.collections.List<Pet> {
         TODO()
     }
 
@@ -79,7 +84,8 @@ class PetApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun getPetById(
-        @PathParam("petId") petId: kotlin.Long): Pet {
+        @PathParam("petId") petId: kotlin.Long
+    ): Pet {
         TODO()
     }
 
@@ -89,7 +95,8 @@ class PetApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun updatePet(
-        @Valid @RequestBody pet: Pet): Pet {
+        @Valid @RequestBody pet: Pet
+    ): Pet {
         TODO()
     }
 
@@ -100,7 +107,8 @@ class PetApiAction @Inject constructor(
     fun updatePetWithForm(
         @PathParam("petId") petId: kotlin.Long, 
         @QueryParam(value = "name") name: kotlin.String? , 
-        @QueryParam(value = "status") status: kotlin.String? ) {
+        @QueryParam(value = "status") status: kotlin.String? 
+    ): Response<Unit> {
         TODO()
     }
 
@@ -112,7 +120,8 @@ class PetApiAction @Inject constructor(
     fun uploadFile(
         @PathParam("petId") petId: kotlin.Long, 
         @QueryParam(value = "additionalMetadata") additionalMetadata: kotlin.String? , 
-        @Valid file: HttpCall): ModelApiResponse {
+        @Valid file: HttpCall
+    ): ModelApiResponse {
         TODO()
     }
 }
diff --git a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt
index ae5b91af0c77..c4c83cae9938 100644
--- a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt
+++ b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/StoreApiAction.kt
@@ -25,6 +25,7 @@ import misk.web.QueryParam
 import misk.web.RequestBody
 import misk.web.RequestContentType
 import misk.web.RequestHeader
+import misk.web.Response
 import misk.web.ResponseContentType
 import misk.web.mediatype.MediaTypes
 import org.openapitools.server.api.model.Order
@@ -40,7 +41,8 @@ class StoreApiAction @Inject constructor(
     @Description("Delete purchase order by ID")
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun deleteOrder(
-        @PathParam("orderId") orderId: kotlin.String) {
+        @PathParam("orderId") orderId: kotlin.String
+    ): Response<Unit> {
         TODO()
     }
 
@@ -48,7 +50,8 @@ class StoreApiAction @Inject constructor(
     @Description("Returns pet inventories by status")
     @ResponseContentType(MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
-    fun getInventory(): kotlin.collections.Map<kotlin.String, kotlin.Int> {
+    fun getInventory(
+    ): kotlin.collections.Map<kotlin.String, kotlin.Int> {
         TODO()
     }
 
@@ -57,7 +60,8 @@ class StoreApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun getOrderById(
-        @Min(1L) @Max(5L) @PathParam("orderId") orderId: kotlin.Long): Order {
+        @Min(1L) @Max(5L) @PathParam("orderId") orderId: kotlin.Long
+    ): Order {
         TODO()
     }
 
@@ -67,7 +71,8 @@ class StoreApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun placeOrder(
-        @Valid @RequestBody order: Order): Order {
+        @Valid @RequestBody order: Order
+    ): Order {
         TODO()
     }
 }
diff --git a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt
index 1107661204f5..153a0e6c5eb1 100644
--- a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt
+++ b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/api/UserApiAction.kt
@@ -25,6 +25,7 @@ import misk.web.QueryParam
 import misk.web.RequestBody
 import misk.web.RequestContentType
 import misk.web.RequestHeader
+import misk.web.Response
 import misk.web.ResponseContentType
 import misk.web.mediatype.MediaTypes
 import org.openapitools.server.api.model.User
@@ -41,7 +42,8 @@ class UserApiAction @Inject constructor(
     @RequestContentType(MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun createUser(
-        @Valid @RequestBody user: User) {
+        @Valid @RequestBody user: User
+    ): Response<Unit> {
         TODO()
     }
 
@@ -50,7 +52,8 @@ class UserApiAction @Inject constructor(
     @RequestContentType(MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun createUsersWithArrayInput(
-        @Valid @RequestBody user: kotlin.Array<User>) {
+        @Valid @RequestBody user: kotlin.collections.List<User>
+    ): Response<Unit> {
         TODO()
     }
 
@@ -59,7 +62,8 @@ class UserApiAction @Inject constructor(
     @RequestContentType(MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun createUsersWithListInput(
-        @Valid @RequestBody user: kotlin.Array<User>) {
+        @Valid @RequestBody user: kotlin.collections.List<User>
+    ): Response<Unit> {
         TODO()
     }
 
@@ -67,7 +71,8 @@ class UserApiAction @Inject constructor(
     @Description("Delete user")
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun deleteUser(
-        @PathParam("username") username: kotlin.String) {
+        @PathParam("username") username: kotlin.String
+    ): Response<Unit> {
         TODO()
     }
 
@@ -76,7 +81,8 @@ class UserApiAction @Inject constructor(
     @ResponseContentType(MediaTypes.APPLICATION_XML, MediaTypes.APPLICATION_JSON)
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun getUserByName(
-        @PathParam("username") username: kotlin.String): User {
+        @PathParam("username") username: kotlin.String
+    ): User {
         TODO()
     }
 
@@ -86,14 +92,16 @@ class UserApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun loginUser(
          @QueryParam(value = "username") username: kotlin.String, 
-         @QueryParam(value = "password") password: kotlin.String): kotlin.String {
+         @QueryParam(value = "password") password: kotlin.String
+    ): kotlin.String {
         TODO()
     }
 
     @Get("/user/logout")
     @Description("Logs out current logged in user session")
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
-    fun logoutUser() {
+    fun logoutUser(
+    ): Response<Unit> {
         TODO()
     }
 
@@ -103,7 +111,8 @@ class UserApiAction @Inject constructor(
     @LogRequestResponse(bodySampling = 1.0, errorBodySampling = 1.0)
     fun updateUser(
         @PathParam("username") username: kotlin.String, 
-        @Valid @RequestBody user: User) {
+        @Valid @RequestBody user: User
+    ): Response<Unit> {
         TODO()
     }
 }
diff --git a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/model/Pet.kt b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/model/Pet.kt
index 0011e60785e4..a48be4bbf406 100644
--- a/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/model/Pet.kt
+++ b/samples/server/petstore/kotlin-misk/src/main/kotlin/org/openapitools/server/api/model/Pet.kt
@@ -7,10 +7,10 @@ import com.squareup.moshi.JsonClass
 @JsonClass(generateAdapter = true)
 data class Pet(
     val name: kotlin.String,
-    val photoUrls: kotlin.Array<kotlin.String>,
+    val photoUrls: kotlin.collections.List<kotlin.String>,
     val id: kotlin.Long? = null,
     val category: Category? = null,
-    val tags: kotlin.Array<Tag>? = null,
+    val tags: kotlin.collections.List<Tag>? = null,
     /** pet status in the store */
     val status: kotlin.String? = null
 )
diff --git a/samples/server/petstore/kotlin-misk/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt b/samples/server/petstore/kotlin-misk/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt
index 445451d8b053..a932999b1668 100644
--- a/samples/server/petstore/kotlin-misk/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt
+++ b/samples/server/petstore/kotlin-misk/src/test/kotlin/org/openapitools/server/api/api/PetApiTest.kt
@@ -47,7 +47,7 @@ internal class PetApiTest {
     @Test
     fun `should handle findPetsByStatus`() {
         val status = TODO()
-        val response: kotlin.Array<Pet> = petApi.findPetsByStatus(status)
+        val response: kotlin.collections.List<Pet> = petApi.findPetsByStatus(status)
     }
 
     /**
@@ -56,7 +56,7 @@ internal class PetApiTest {
     @Test
     fun `should handle findPetsByTags`() {
         val tags = TODO()
-        val response: kotlin.Array<Pet> = petApi.findPetsByTags(tags)
+        val response: kotlin.collections.List<Pet> = petApi.findPetsByTags(tags)
     }
 
     /**