diff --git a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/attachments/route.ts b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/attachments/route.ts
index fd8bdeef..bdec23a5 100644
--- a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/attachments/route.ts
+++ b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/attachments/route.ts
@@ -21,7 +21,7 @@ export type ListAttachmentsResponder = {
 } & KoaRuntimeResponder
 
 export type ListAttachments = (
-  params: Params<void, void, void>,
+  params: Params<void, void, void, void>,
   respond: ListAttachmentsResponder,
   ctx: { request: NextRequest },
 ) => Promise<KoaRuntimeResponse<unknown>>
@@ -31,7 +31,7 @@ export type UploadAttachmentResponder = {
 } & KoaRuntimeResponder
 
 export type UploadAttachment = (
-  params: Params<void, void, t_UploadAttachmentBodySchema>,
+  params: Params<void, void, t_UploadAttachmentBodySchema, void>,
   respond: UploadAttachmentResponder,
   ctx: { request: NextRequest },
 ) => Promise<KoaRuntimeResponse<unknown>>
@@ -47,6 +47,7 @@ export const _GET =
       // TODO: this swallows repeated parameters
       query: undefined,
       body: undefined,
+      headers: undefined,
     }
 
     const responder = {
@@ -86,6 +87,7 @@ export const _POST =
         await request.json(),
         RequestInputType.RequestBody,
       ),
+      headers: undefined,
     }
 
     const responder = {
diff --git a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/clients/client.ts b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/clients/client.ts
index 784b61c3..e39c41ab 100644
--- a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/clients/client.ts
+++ b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/clients/client.ts
@@ -315,6 +315,3 @@ export class ApiClient extends AbstractFetchClient {
     return this._fetch(url, { method: "POST", body, ...opts, headers }, timeout)
   }
 }
-
-export { ApiClient as ApiClient }
-export type { ApiClientConfig as ApiClientConfig }
diff --git a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/items/route.ts b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/items/route.ts
index 97063d41..046cd011 100644
--- a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/items/route.ts
+++ b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/items/route.ts
@@ -35,7 +35,7 @@ export type GetTodoListItemsResponder = {
 } & KoaRuntimeResponder
 
 export type GetTodoListItems = (
-  params: Params<t_GetTodoListItemsParamSchema, void, void>,
+  params: Params<t_GetTodoListItemsParamSchema, void, void, void>,
   respond: GetTodoListItemsResponder,
   ctx: { request: NextRequest },
 ) => Promise<KoaRuntimeResponse<unknown>>
@@ -48,7 +48,8 @@ export type CreateTodoListItem = (
   params: Params<
     t_CreateTodoListItemParamSchema,
     void,
-    t_CreateTodoListItemBodySchema
+    t_CreateTodoListItemBodySchema,
+    void
   >,
   respond: CreateTodoListItemResponder,
   ctx: { request: NextRequest },
@@ -71,6 +72,7 @@ export const _GET =
       // TODO: this swallows repeated parameters
       query: undefined,
       body: undefined,
+      headers: undefined,
     }
 
     const responder = {
@@ -131,6 +133,7 @@ export const _POST =
         await request.json(),
         RequestInputType.RequestBody,
       ),
+      headers: undefined,
     }
 
     const responder = {
diff --git a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/route.ts b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/route.ts
index ed581286..525de2b3 100644
--- a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/route.ts
+++ b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/[listId]/route.ts
@@ -32,7 +32,7 @@ export type GetTodoListByIdResponder = {
 } & KoaRuntimeResponder
 
 export type GetTodoListById = (
-  params: Params<t_GetTodoListByIdParamSchema, void, void>,
+  params: Params<t_GetTodoListByIdParamSchema, void, void, void>,
   respond: GetTodoListByIdResponder,
   ctx: { request: NextRequest },
 ) => Promise<KoaRuntimeResponse<unknown>>
@@ -47,7 +47,8 @@ export type UpdateTodoListById = (
   params: Params<
     t_UpdateTodoListByIdParamSchema,
     void,
-    t_UpdateTodoListByIdBodySchema
+    t_UpdateTodoListByIdBodySchema,
+    void
   >,
   respond: UpdateTodoListByIdResponder,
   ctx: { request: NextRequest },
@@ -60,7 +61,7 @@ export type DeleteTodoListByIdResponder = {
 } & KoaRuntimeResponder
 
 export type DeleteTodoListById = (
-  params: Params<t_DeleteTodoListByIdParamSchema, void, void>,
+  params: Params<t_DeleteTodoListByIdParamSchema, void, void, void>,
   respond: DeleteTodoListByIdResponder,
   ctx: { request: NextRequest },
 ) => Promise<KoaRuntimeResponse<unknown>>
@@ -82,6 +83,7 @@ export const _GET =
       // TODO: this swallows repeated parameters
       query: undefined,
       body: undefined,
+      headers: undefined,
     }
 
     const responder = {
@@ -133,6 +135,7 @@ export const _PUT =
         await request.json(),
         RequestInputType.RequestBody,
       ),
+      headers: undefined,
     }
 
     const responder = {
@@ -178,6 +181,7 @@ export const _DELETE =
       // TODO: this swallows repeated parameters
       query: undefined,
       body: undefined,
+      headers: undefined,
     }
 
     const responder = {
diff --git a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/route.ts b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/route.ts
index caab98cf..6d351ccd 100644
--- a/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/route.ts
+++ b/integration-tests/typescript-nextjs/src/generated/todo-lists.yaml/list/route.ts
@@ -22,7 +22,7 @@ export type GetTodoListsResponder = {
 } & KoaRuntimeResponder
 
 export type GetTodoLists = (
-  params: Params<void, t_GetTodoListsQuerySchema, void>,
+  params: Params<void, t_GetTodoListsQuerySchema, void, void>,
   respond: GetTodoListsResponder,
   ctx: { request: NextRequest },
 ) => Promise<KoaRuntimeResponse<unknown>>
@@ -58,6 +58,7 @@ export const _GET =
         RequestInputType.QueryString,
       ),
       body: undefined,
+      headers: undefined,
     }
 
     const responder = {