diff --git a/packages/core/src/bridge/bridge-contacts.ts b/packages/core/src/bridge/bridge-contacts.ts
index 63c2bbaa..23f537f1 100644
--- a/packages/core/src/bridge/bridge-contacts.ts
+++ b/packages/core/src/bridge/bridge-contacts.ts
@@ -208,9 +208,10 @@ export async function fetchGroupMemberList(bridge: Bridge, groupId: number): Pro
 
 export async function fetchUserProfile(bridge: Bridge, uin: number): Promise<UserProfileInfo> {
   const keys = [20002, 27394, 20009, 20031, 101, 103, 102, 20020, 20003, 20026, 105, 27372, 27406, 20037];
+  // Only `uin` and `keys` — see OidbUserInfoRequestSchema for why
+  // sending field 2 makes the server reject the request.
   const body = {
     uin,
-    field2: 0,
     keys: keys.map(k => ({ key: k })),
   };
 
diff --git a/packages/core/src/bridge/proto/oidb-action.ts b/packages/core/src/bridge/proto/oidb-action.ts
index b4b28a1a..ec521dff 100644
--- a/packages/core/src/bridge/proto/oidb-action.ts
+++ b/packages/core/src/bridge/proto/oidb-action.ts
@@ -190,10 +190,14 @@ export const OidbUserInfoKeySchema = {
   key: { field: 1, type: 'uint32' as const },
 } satisfies ProtoSchema;
 
+// Field 2 USED to be `field2: uint32 = 0`, but newer QQ NT versions
+// reinterpret field 2 as `uid: string` / `openid: string` and reject
+// the request with "one of uid/openid is invaild" when a varint 0
+// shows up there. NapCat's schema (Oidb.0XFE1_2.ts) only emits `uin`
+// and `key[]`, so we match that exactly.
 export const OidbUserInfoRequestSchema = {
-  uin:    { field: 1, type: 'uint32' as const },
-  field2: { field: 2, type: 'uint32' as const },
-  keys:   { field: 3, type: 'repeated_message' as const, schema: OidbUserInfoKeySchema },
+  uin:  { field: 1, type: 'uint32' as const },
+  keys: { field: 3, type: 'repeated_message' as const, schema: OidbUserInfoKeySchema },
 } satisfies ProtoSchema;
 
 export const OidbTwoNumberSchema = {