diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache
index 150fff84dbd..20070e1b86b 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/api.mustache
@@ -73,11 +73,11 @@ import {{packageName}}.infrastructure.toMultiValue
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache
index 90080744c69..9a15406f1bb 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache
@@ -237,12 +237,13 @@ import java.io.File
                     response.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
                     response.body{{#jvm-okhttp3}}(){{/jvm-okhttp3}}?.string(),
                     response.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
                     response.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
                     response.body{{#jvm-okhttp3}}(){{/jvm-okhttp3}}?.string(),
                     response.code{{#jvm-okhttp3}}(){{/jvm-okhttp3}},
                     response.headers{{#jvm-okhttp3}}(){{/jvm-okhttp3}}.toMultimap()
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiInfrastructureResponse.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiInfrastructureResponse.kt.mustache
index 09e6301cee5..98be9afd5fb 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiInfrastructureResponse.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiInfrastructureResponse.kt.mustache
@@ -4,7 +4,9 @@ package {{packageName}}.infrastructure
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-{{#nonPublicApi}}internal {{/nonPublicApi}}abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+{{#nonPublicApi}}internal {{/nonPublicApi}}interface Response
+
+{{#nonPublicApi}}internal {{/nonPublicApi}}abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ package {{packageName}}.infrastructure
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 {{#nonPublicApi}}internal {{/nonPublicApi}}class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/Errors.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/Errors.kt.mustache
index 45b9a9e3f32..7c428ad655f 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/Errors.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/Errors.kt.mustache
@@ -3,14 +3,14 @@ package {{packageName}}.infrastructure
 
 import java.lang.RuntimeException
 
-{{#nonPublicApi}}internal {{/nonPublicApi}}open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+{{#nonPublicApi}}internal {{/nonPublicApi}}open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     {{#nonPublicApi}}internal {{/nonPublicApi}}companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-{{#nonPublicApi}}internal {{/nonPublicApi}}open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+{{#nonPublicApi}}internal {{/nonPublicApi}}open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     {{#nonPublicApi}}internal {{/nonPublicApi}}companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 1638d460c68..2e3b24ae2ea 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 18355b552ae..1399a0ca1cf 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 4f18a92d223..a7d99762fd8 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5dcfe386089..0907e471f43 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index f1a8aecc914..9dc8d8dbbfa 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index cb72e1568f3..97248ed4cfd 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -190,11 +190,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -231,11 +231,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -271,11 +271,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -313,11 +313,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -356,11 +356,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 18355b552ae..1399a0ca1cf 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 4f18a92d223..a7d99762fd8 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index de65b44cd9a..d56cfcc2a32 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index f1a8aecc914..9dc8d8dbbfa 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 1638d460c68..2e3b24ae2ea 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 18355b552ae..1399a0ca1cf 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 4f18a92d223..a7d99762fd8 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5670d3c132b..a03ba02ff08 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index f1a8aecc914..9dc8d8dbbfa 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index d4b862a21ae..51247617d9c 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ internal class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2")
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index f1b775deba8..893601a3220 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ internal class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 0703be33057..d486ee7dc52 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ internal class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2"
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index f786e8d0f2d..0055340ab35 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ internal open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index 6f38b7aa18c..c618544573e 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ internal enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-internal abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+internal interface Response
+
+internal abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ internal class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 internal class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 0c5925723b2..204b69dcb08 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-internal open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+internal open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     internal companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-internal open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+internal open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     internal companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 3b1ecae4210..de4ab6dbb83 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 1a889435cd2..a2deaaa89d1 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 3c561969920..d4f2f9f8c24 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5670d3c132b..a03ba02ff08 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index 51c1f14b2a8..77066de4e55 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 1638d460c68..2e3b24ae2ea 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 18355b552ae..1399a0ca1cf 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 4f18a92d223..a7d99762fd8 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 9551a3a0c92..2669e67f34f 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -156,12 +156,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers().toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message(),
                     response.body()?.string(),
                     response.code(),
                     response.headers().toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message(),
                     response.body()?.string(),
                     response.code(),
                     response.headers().toMultimap()
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index f1a8aecc914..9dc8d8dbbfa 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index e475ddc88d8..69d1e725e49 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 18355b552ae..1399a0ca1cf 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 4f18a92d223..a7d99762fd8 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5670d3c132b..a03ba02ff08 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index f1a8aecc914..9dc8d8dbbfa 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 1638d460c68..2e3b24ae2ea 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 18355b552ae..1399a0ca1cf 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 4f18a92d223..a7d99762fd8 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5670d3c132b..a03ba02ff08 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index f1a8aecc914..9dc8d8dbbfa 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
index 1638d460c68..2e3b24ae2ea 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/PetApi.kt
@@ -59,11 +59,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -100,11 +100,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -144,11 +144,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -188,11 +188,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -229,11 +229,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -269,11 +269,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -311,11 +311,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -354,11 +354,11 @@ class PetApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCli
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
index 18355b552ae..1399a0ca1cf 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -58,11 +58,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -139,11 +139,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -180,11 +180,11 @@ class StoreApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiC
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
index 4f18a92d223..a7d99762fd8 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/apis/UserApi.kt
@@ -58,11 +58,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -98,11 +98,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -138,11 +138,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -178,11 +178,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -219,11 +219,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -265,11 +265,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -304,11 +304,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
@@ -345,11 +345,11 @@ class UserApi(basePath: kotlin.String = "http://petstore.swagger.io/v2") : ApiCl
             ResponseType.Redirection -> throw UnsupportedOperationException("Client does not support Redirection responses.")
             ResponseType.ClientError -> {
                 val localVarError = localVarResponse as ClientError<*>
-                throw ClientException(localVarError.body as? String ?: "Client error", localVarError.statusCode)
+                throw ClientException("Client error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
             ResponseType.ServerError -> {
                 val localVarError = localVarResponse as ServerError<*>
-                throw ServerException(localVarError.message ?: "Server error", localVarError.statusCode)
+                throw ServerException("Server error : ${localVarError.statusCode} ${localVarError.message.orEmpty()}", localVarError.statusCode, localVarResponse)
             }
         }
     }
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5670d3c132b..a03ba02ff08 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -158,12 +158,13 @@ open class ApiClient(val baseUrl: String) {
                     response.headers.toMultimap()
             )
             response.isClientError -> return ClientError(
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
             )
             else -> return ServerError(
-                    null,
+                    response.message,
                     response.body?.string(),
                     response.code,
                     response.headers.toMultimap()
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
index f1a8aecc914..9dc8d8dbbfa 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiInfrastructureResponse.kt
@@ -4,7 +4,9 @@ enum class ResponseType {
     Success, Informational, Redirection, ClientError, ServerError
 }
 
-abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType) {
+interface Response
+
+abstract class ApiInfrastructureResponse<T>(val responseType: ResponseType): Response {
     abstract val statusCode: Int
     abstract val headers: Map<String,List<String>>
 }
@@ -27,6 +29,7 @@ class Redirection<T>(
 ) : ApiInfrastructureResponse<T>(ResponseType.Redirection)
 
 class ClientError<T>(
+    val message: String? = null,
     val body: Any? = null,
     override val statusCode: Int = -1,
     override val headers: Map<String, List<String>> = mapOf()
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
index 41f529a5f36..b5310e71f13 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
@@ -3,14 +3,14 @@ package org.openapitools.client.infrastructure
 
 import java.lang.RuntimeException
 
-open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ClientException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 123L
     }
 }
 
-open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1) : RuntimeException(message) {
+open class ServerException(message: kotlin.String? = null, val statusCode: Int = -1, val response: Response? = null) : RuntimeException(message) {
 
     companion object {
         private const val serialVersionUID: Long = 456L