diff --git a/src/Application/TakeoutSaaS.Application/Identity/Commands/BatchIdentityUserOperationCommand.cs b/src/Application/TakeoutSaaS.Application/Identity/Commands/BatchIdentityUserOperationCommand.cs
index a627339..827e1ed 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Commands/BatchIdentityUserOperationCommand.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Commands/BatchIdentityUserOperationCommand.cs
@@ -10,7 +10,7 @@ namespace TakeoutSaaS.Application.Identity.Commands;
 public sealed record BatchIdentityUserOperationCommand : IRequest<BatchIdentityUserOperationResult>
 {
     /// <summary>
-    /// 目标租户 ID（超级管理员可选）。
+    /// 目标租户 ID（可选，默认当前登录租户；禁止跨租户操作）。
     /// </summary>
     public long? TenantId { get; init; }
 
diff --git a/src/Application/TakeoutSaaS.Application/Identity/Commands/ChangeIdentityUserStatusCommand.cs b/src/Application/TakeoutSaaS.Application/Identity/Commands/ChangeIdentityUserStatusCommand.cs
index 3220376..1e6dd30 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Commands/ChangeIdentityUserStatusCommand.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Commands/ChangeIdentityUserStatusCommand.cs
@@ -14,7 +14,7 @@ public sealed record ChangeIdentityUserStatusCommand : IRequest<bool>
     public long UserId { get; init; }
 
     /// <summary>
-    /// 目标租户 ID（超级管理员可选）。
+    /// 目标租户 ID（可选，默认当前登录租户；禁止跨租户操作）。
     /// </summary>
     public long? TenantId { get; init; }
 
diff --git a/src/Application/TakeoutSaaS.Application/Identity/Commands/CreateIdentityUserCommand.cs b/src/Application/TakeoutSaaS.Application/Identity/Commands/CreateIdentityUserCommand.cs
index c9f7c3d..e528df1 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Commands/CreateIdentityUserCommand.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Commands/CreateIdentityUserCommand.cs
@@ -11,7 +11,7 @@ namespace TakeoutSaaS.Application.Identity.Commands;
 public sealed record CreateIdentityUserCommand : IRequest<UserDetailDto>
 {
     /// <summary>
-    /// 目标租户 ID（超级管理员可选）。
+    /// 目标租户 ID（可选，默认当前登录租户；禁止跨租户操作）。
     /// </summary>
     public long? TenantId { get; init; }
 
diff --git a/src/Application/TakeoutSaaS.Application/Identity/Commands/DeleteIdentityUserCommand.cs b/src/Application/TakeoutSaaS.Application/Identity/Commands/DeleteIdentityUserCommand.cs
index 5fc1ce5..bf056f6 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Commands/DeleteIdentityUserCommand.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Commands/DeleteIdentityUserCommand.cs
@@ -13,7 +13,7 @@ public sealed record DeleteIdentityUserCommand : IRequest<bool>
     public long UserId { get; init; }
 
     /// <summary>
-    /// 目标租户 ID（超级管理员可选）。
+    /// 目标租户 ID（可选，默认当前登录租户；禁止跨租户操作）。
     /// </summary>
     public long? TenantId { get; init; }
 }
diff --git a/src/Application/TakeoutSaaS.Application/Identity/Commands/ResetIdentityUserPasswordCommand.cs b/src/Application/TakeoutSaaS.Application/Identity/Commands/ResetIdentityUserPasswordCommand.cs
index 124f1e6..9cda914 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Commands/ResetIdentityUserPasswordCommand.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Commands/ResetIdentityUserPasswordCommand.cs
@@ -14,7 +14,7 @@ public sealed record ResetIdentityUserPasswordCommand : IRequest<ResetIdentityUs
     public long UserId { get; init; }
 
     /// <summary>
-    /// 目标租户 ID（超级管理员可选）。
+    /// 目标租户 ID（可选，默认当前登录租户；禁止跨租户操作）。
     /// </summary>
     public long? TenantId { get; init; }
 }
diff --git a/src/Application/TakeoutSaaS.Application/Identity/Commands/RestoreIdentityUserCommand.cs b/src/Application/TakeoutSaaS.Application/Identity/Commands/RestoreIdentityUserCommand.cs
index 6d6515a..c28ae28 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Commands/RestoreIdentityUserCommand.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Commands/RestoreIdentityUserCommand.cs
@@ -13,7 +13,7 @@ public sealed record RestoreIdentityUserCommand : IRequest<bool>
     public long UserId { get; init; }
 
     /// <summary>
-    /// 目标租户 ID（超级管理员可选）。
+    /// 目标租户 ID（可选，默认当前登录租户；禁止跨租户操作）。
     /// </summary>
     public long? TenantId { get; init; }
 }
diff --git a/src/Application/TakeoutSaaS.Application/Identity/Commands/UpdateIdentityUserCommand.cs b/src/Application/TakeoutSaaS.Application/Identity/Commands/UpdateIdentityUserCommand.cs
index 99025bd..9fd7734 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Commands/UpdateIdentityUserCommand.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Commands/UpdateIdentityUserCommand.cs
@@ -15,7 +15,7 @@ public sealed record UpdateIdentityUserCommand : IRequest<UserDetailDto?>
     public long UserId { get; init; }
 
     /// <summary>
-    /// 目标租户 ID（超级管理员可选）。
+    /// 目标租户 ID（可选，默认当前登录租户；禁止跨租户操作）。
     /// </summary>
     public long? TenantId { get; init; }
 
diff --git a/src/Application/TakeoutSaaS.Application/Identity/Queries/SearchIdentityUsersQuery.cs b/src/Application/TakeoutSaaS.Application/Identity/Queries/SearchIdentityUsersQuery.cs
index 6067610..9ab3288 100644
--- a/src/Application/TakeoutSaaS.Application/Identity/Queries/SearchIdentityUsersQuery.cs
+++ b/src/Application/TakeoutSaaS.Application/Identity/Queries/SearchIdentityUsersQuery.cs
@@ -11,7 +11,7 @@ namespace TakeoutSaaS.Application.Identity.Queries;
 public sealed record SearchIdentityUsersQuery : IRequest<PagedResult<UserListItemDto>>
 {
     /// <summary>
-    /// 租户 ID（超级管理员可选）。
+    /// 租户 ID（可选，默认当前登录租户；禁止跨租户查询）。
     /// </summary>
     public long? TenantId { get; init; }
 
diff --git a/src/Infrastructure/TakeoutSaaS.Infrastructure/Dictionary/Persistence/Seeds/InitialDictionaries.sql b/src/Infrastructure/TakeoutSaaS.Infrastructure/Dictionary/Persistence/Seeds/InitialDictionaries.sql
index 10dd21d..a8f6d33 100644
--- a/src/Infrastructure/TakeoutSaaS.Infrastructure/Dictionary/Persistence/Seeds/InitialDictionaries.sql
+++ b/src/Infrastructure/TakeoutSaaS.Infrastructure/Dictionary/Persistence/Seeds/InitialDictionaries.sql
@@ -73,12 +73,11 @@ ON CONFLICT ("TenantId", "GroupId", "Key") DO NOTHING;
 -- ========================================
 INSERT INTO dictionary_groups ("Id", "TenantId", "Code", "Name", "Scope", "AllowOverride", "IsEnabled", "Description", "CreatedAt", "CreatedBy")
 VALUES
-  (1005, 0, 'user_role', '用户角色', 1, false, true, '系统用户角色类型 (平台级，不可覆盖)', CURRENT_TIMESTAMP, 0)
+  (1005, 0, 'user_role', '用户角色', 1, false, true, '系统用户角色类型 (系统级，不可覆盖)', CURRENT_TIMESTAMP, 0)
 ON CONFLICT ("TenantId", "Code") DO NOTHING;
 
 INSERT INTO dictionary_items ("Id", "TenantId", "GroupId", "Key", "Value", "IsDefault", "IsEnabled", "SortOrder", "Description", "CreatedAt", "CreatedBy")
 VALUES
-  (10051, 0, 1005, 'PLATFORM_ADMIN', '{"zh-CN":"平台管理员","en":"Platform Admin"}', false, true, 10, '平台超级管理员', CURRENT_TIMESTAMP, 0),
   (10052, 0, 1005, 'TENANT_ADMIN', '{"zh-CN":"租户管理员","en":"Tenant Admin"}', false, true, 20, '租户企业管理员', CURRENT_TIMESTAMP, 0),
   (10053, 0, 1005, 'TENANT_USER', '{"zh-CN":"租户员工","en":"Tenant User"}', true, true, 30, '租户普通员工', CURRENT_TIMESTAMP, 0),
   (10054, 0, 1005, 'CUSTOMER', '{"zh-CN":"顾客","en":"Customer"}', false, true, 40, '终端用户/顾客', CURRENT_TIMESTAMP, 0)