diff --git a/packages/types/src/sdk/koa.ts b/packages/types/src/sdk/koa.ts
index deb457d009..826b7b371c 100644
--- a/packages/types/src/sdk/koa.ts
+++ b/packages/types/src/sdk/koa.ts
@@ -47,7 +47,7 @@ export interface BBRequest<RequestBody> extends Request {
 export interface Ctx<RequestBody = any, ResponseBody = any> extends Context {
   request: BBRequest<RequestBody>
   body: ResponseBody
-  userAgent?: UserAgentContext["userAgent"]
+  userAgent: UserAgentContext["userAgent"]
   state: { nonce?: string }
 }