diff --git a/src/c2se/backend/identity.rs b/src/c2se/backend/identity.rs
index 8f27cf6..c8b3a15 100644
--- a/src/c2se/backend/identity.rs
+++ b/src/c2se/backend/identity.rs
@@ -28,8 +28,6 @@ pub struct SigninRequest {
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct SigninResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(string, optional, tag = "2")]
-  pub session_id: ::core::option::Option<::prost::alloc::string::String>,
+  #[prost(string, tag = "1")]
+  pub session_id: ::prost::alloc::string::String,
 }
diff --git a/src/c2se/backend/member.rs b/src/c2se/backend/member.rs
index 8f99d63..466bf76 100644
--- a/src/c2se/backend/member.rs
+++ b/src/c2se/backend/member.rs
@@ -1,43 +1,36 @@
-use crate::protobuf::rpc;
-use crate::protobuf::pagination;
 use crate::models::member;
+use crate::protobuf::pagination;
 
 const SUBJECT: &str = "bet.beteran.c2se.backend.member";
 
-pub const SUBJECT_LIST_MEMBERS: &str =
-  const_format::concatcp!(SUBJECT, ".ListMembers");
+pub const SUBJECT_LIST_MEMBERS: &str = const_format::concatcp!(SUBJECT, ".ListMembers");
 /// subject = bet.beteran.c2se.backend.member.ListMembers
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ListMembersRequest {
-    #[prost(message, optional, tag="1")]
-    pub pagination: ::core::option::Option<pagination::Pagination>,
-    #[prost(message, repeated, tag="2")]
-    pub searches: ::prost::alloc::vec::Vec<pagination::Search>,
-    #[prost(message, repeated, tag="3")]
-    pub sorts: ::prost::alloc::vec::Vec<pagination::Sort>,
+  #[prost(message, optional, tag = "1")]
+  pub pagination: ::core::option::Option<pagination::Pagination>,
+  #[prost(message, repeated, tag = "2")]
+  pub searches: ::prost::alloc::vec::Vec<pagination::Search>,
+  #[prost(message, repeated, tag = "3")]
+  pub sorts: ::prost::alloc::vec::Vec<pagination::Sort>,
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct ListMembersResponse {
-    #[prost(message, optional, tag="1")]
-    pub error: ::core::option::Option<rpc::Error>,
-    #[prost(message, repeated, tag="2")]
-    pub members: ::prost::alloc::vec::Vec<member::Member>,
+  #[prost(message, repeated, tag = "1")]
+  pub members: ::prost::alloc::vec::Vec<member::Member>,
 }
 
-pub const SUBJECT_GET_MEMBER: &str =
-  const_format::concatcp!(SUBJECT, ".GetMember");
+pub const SUBJECT_GET_MEMBER: &str = const_format::concatcp!(SUBJECT, ".GetMember");
 /// subject = bet.beteran.c2se.backend.member.GetMember
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct GetMemberRequest {
-    #[prost(string, tag="1")]
-    pub id: ::prost::alloc::string::String,
+  #[prost(string, tag = "1")]
+  pub id: ::prost::alloc::string::String,
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct GetMemberResponse {
-    #[prost(message, optional, tag="1")]
-    pub error: ::core::option::Option<rpc::Error>,
-    #[prost(message, optional, tag="2")]
-    pub member: ::core::option::Option<member::Member>,
+  #[prost(message, optional, tag = "1")]
+  pub member: ::core::option::Option<member::Member>,
 }
 
 pub const SUBJECT_GET_MEMBER_BY_USERNAME: &str =
@@ -45,13 +38,11 @@ pub const SUBJECT_GET_MEMBER_BY_USERNAME: &str =
 /// subject = bet.beteran.c2se.backend.member.GetMemberByUsername
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct GetMemberByUsernameRequest {
-    #[prost(string, tag="1")]
-    pub username: ::prost::alloc::string::String,
+  #[prost(string, tag = "1")]
+  pub username: ::prost::alloc::string::String,
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct GetMemberByUsernameResponse {
-    #[prost(message, optional, tag="1")]
-    pub error: ::core::option::Option<rpc::Error>,
-    #[prost(message, optional, tag="2")]
-    pub member: ::core::option::Option<member::Member>,
+  #[prost(message, optional, tag = "1")]
+  pub member: ::core::option::Option<member::Member>,
 }
diff --git a/src/c2se/common/identity.rs b/src/c2se/common/identity.rs
index d38c4d0..0b74cfe 100644
--- a/src/c2se/common/identity.rs
+++ b/src/c2se/common/identity.rs
@@ -10,10 +10,8 @@ pub struct CheckUsernameForDuplicationRequest {
 
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct CheckUsernameForDuplicationResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(bool, optional, tag = "2")]
-  pub duplicated: ::core::option::Option<bool>,
+  #[prost(bool, tag = "1")]
+  pub duplicated: bool,
 }
 
 #[derive(Clone, PartialEq, ::prost::Message)]
@@ -24,10 +22,8 @@ pub struct CheckNicknameForDuplicationRequest {
 
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct CheckNicknameForDuplicationResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(bool, optional, tag = "2")]
-  pub duplicated: ::core::option::Option<bool>,
+  #[prost(bool, tag = "1")]
+  pub duplicated: bool,
 }
 
 #[derive(Clone, PartialEq, ::prost::Message)]
@@ -35,10 +31,8 @@ pub struct CaptchaRequest {}
 
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct CaptchaResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(string, optional, tag = "2")]
-  pub token: ::core::option::Option<::prost::alloc::string::String>,
-  #[prost(string, optional, tag = "3")]
-  pub image: ::core::option::Option<::prost::alloc::string::String>,
+  #[prost(string, tag = "1")]
+  pub token: ::prost::alloc::string::String,
+  #[prost(string, tag = "2")]
+  pub image: ::prost::alloc::string::String,
 }
diff --git a/src/c2se/frontend/identity.rs b/src/c2se/frontend/identity.rs
index 5401339..9a8e2fd 100644
--- a/src/c2se/frontend/identity.rs
+++ b/src/c2se/frontend/identity.rs
@@ -29,8 +29,6 @@ pub struct SigninRequest {
 
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct SigninResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(string, optional, tag = "2")]
-  pub session_id: ::core::option::Option<::prost::alloc::string::String>,
+  #[prost(string, tag = "1")]
+  pub session_id: ::prost::alloc::string::String,
 }
diff --git a/src/protobuf/rpc.rs b/src/protobuf/rpc.rs
index 2150e09..0809c09 100644
--- a/src/protobuf/rpc.rs
+++ b/src/protobuf/rpc.rs
@@ -15,6 +15,6 @@ impl fmt::Display for Error {
       f,
       "Error code: {}, message: {:?}, data: {:?}",
       self.code, self.message, self.data
-    ) // user-facing output
+    )
   }
 }
diff --git a/src/ss/member/identity.rs b/src/ss/member/identity.rs
index b96624e..1dfb9b2 100644
--- a/src/ss/member/identity.rs
+++ b/src/ss/member/identity.rs
@@ -15,10 +15,8 @@ pub struct CheckUsernameForDuplicationRequest {
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct CheckUsernameForDuplicationResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(bool, optional, tag = "2")]
-  pub duplicated: ::core::option::Option<bool>,
+  #[prost(bool, tag = "1")]
+  pub duplicated: bool,
 }
 
 pub const SUBJECT_CHECK_NICKNAME_FOR_DUPLICATION: &str =
@@ -33,10 +31,8 @@ pub struct CheckNicknameForDuplicationRequest {
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct CheckNicknameForDuplicationResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(bool, optional, tag = "2")]
-  pub duplicated: ::core::option::Option<bool>,
+  #[prost(bool, tag = "1")]
+  pub duplicated: bool,
 }
 
 pub const SUBJECT_CAPTCHA: &str = const_format::concatcp!(SUBJECT, ".Captcha");
@@ -48,12 +44,10 @@ pub struct CaptchaRequest {
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct CaptchaResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(string, optional, tag = "2")]
-  pub token: ::core::option::Option<::prost::alloc::string::String>,
-  #[prost(string, optional, tag = "3")]
-  pub image: ::core::option::Option<::prost::alloc::string::String>,
+  #[prost(string, tag = "1")]
+  pub token: ::prost::alloc::string::String,
+  #[prost(string, tag = "2")]
+  pub image: ::prost::alloc::string::String,
 }
 
 pub const SUBJECT_SIGNIN: &str = const_format::concatcp!(SUBJECT, ".Signin");
@@ -73,8 +67,6 @@ pub struct SigninRequest {
 }
 #[derive(Clone, PartialEq, ::prost::Message)]
 pub struct SigninResponse {
-  #[prost(message, optional, tag = "1")]
-  pub error: ::core::option::Option<rpc::Error>,
-  #[prost(string, optional, tag = "2")]
-  pub session_id: ::core::option::Option<::prost::alloc::string::String>,
+  #[prost(string, tag = "1")]
+  pub session_id: ::prost::alloc::string::String,
 }