diff --git a/src/GmRelay.DiscordBot/Features/Sessions/DiscordNewSessionHandler.cs b/src/GmRelay.DiscordBot/Features/Sessions/DiscordNewSessionHandler.cs
index 55d2c7e..5de5f36 100644
--- a/src/GmRelay.DiscordBot/Features/Sessions/DiscordNewSessionHandler.cs
+++ b/src/GmRelay.DiscordBot/Features/Sessions/DiscordNewSessionHandler.cs
@@ -75,7 +75,9 @@ public sealed class DiscordNewSessionHandler(
               FROM group_managers gm
               JOIN players p ON p.id = gm.player_id
               JOIN game_groups g ON g.id = gm.group_id
-              WHERE g.platform = 'Discord' AND g.external_group_id = @GuildId",
+              WHERE g.platform = 'Discord'
+                AND p.platform = 'Discord'
+                AND g.external_group_id = @GuildId",
             new { GuildId = guildId });
 
         if (!permissionChecker.CanManageSchedule(guildOwnerId, userId, dbManagerUserIds, resolvedPermissions))
diff --git a/src/GmRelay.Web/Components/Pages/GroupDetails.razor b/src/GmRelay.Web/Components/Pages/GroupDetails.razor
index 6dbb686..4555f65 100644
--- a/src/GmRelay.Web/Components/Pages/GroupDetails.razor
+++ b/src/GmRelay.Web/Components/Pages/GroupDetails.razor
@@ -40,8 +40,8 @@
                     </span>
                     @if (groupManagement.CurrentUserIsOwner && manager.Role == GroupManagerRoleExtensions.CoGmValue)
                     {
-                        <button type="button" class="btn-gm btn-gm-outline" style="font-size: 0.75rem; padding: 0.25rem 0.5rem;" disabled="@(removingCoGmId == manager.ExternalUserId)" @onclick="() => RemoveCoGm(manager.ExternalUserId ?? manager.TelegramId.ToString())">
-                            @(removingCoGmId == manager.ExternalUserId ? "⏳ Удаляем..." : "Убрать")
+                        <button type="button" class="btn-gm btn-gm-outline" style="font-size: 0.75rem; padding: 0.25rem 0.5rem;" disabled="@(removingCoGmId == ManagerKey(manager))" @onclick="() => RemoveCoGm(manager)">
+                            @(removingCoGmId == ManagerKey(manager) ? "⏳ Удаляем..." : "Убрать")
                         </button>
                     }
                 }
@@ -52,8 +52,8 @@
                 <EditForm Model="@coGmModel" OnValidSubmit="AddCoGm">
                     <div class="batch-bulk-fields">
                         <div class="gm-form-group">
-                            <label class="gm-form-label">Telegram ID co-GM</label>
-                            <InputNumber @bind-Value="coGmModel.TelegramId" class="gm-form-control" min="1" />
+                            <label class="gm-form-label">@CoGmIdLabel</label>
+                            <InputText @bind-Value="coGmModel.ExternalUserId" class="gm-form-control" />
                         </div>
                         <div class="gm-form-group">
                             <label class="gm-form-label">Имя</label>
@@ -61,7 +61,7 @@
                         </div>
                         <div class="gm-form-group">
                             <label class="gm-form-label">Username</label>
-                            <InputText @bind-Value="coGmModel.TelegramUsername" class="gm-form-control" />
+                            <InputText @bind-Value="coGmModel.ExternalUsername" class="gm-form-control" />
                         </div>
                     </div>
                     <button type="submit" class="btn-gm btn-gm-primary" disabled="@isAddingCoGm">
@@ -405,6 +405,7 @@
     private Guid? processingTemplateId;
     private string? removingCoGmId;
     private bool isAddingCoGm;
+    private string? currentPlatform;
     private string? externalUserId;
     private string? errorMessage;
     private string? successMessage;
@@ -423,6 +424,7 @@
             return;
         }
 
+        currentPlatform = platform;
         await LoadSessions();
     }
 
@@ -458,9 +460,16 @@
         errorMessage = null;
         successMessage = null;
 
-        if (!coGmModel.TelegramId.HasValue || coGmModel.TelegramId.Value <= 0)
+        var coGmExternalUserId = coGmModel.ExternalUserId.Trim();
+        if (coGmExternalUserId.Length == 0)
         {
-            errorMessage = "Telegram ID co-GM должен быть положительным числом.";
+            errorMessage = $"{CoGmIdLabel} должен быть заполнен.";
+            return;
+        }
+
+        if (!IsValidPlatformUserId(CoGmPlatform, coGmExternalUserId))
+        {
+            errorMessage = $"{CoGmIdLabel} должен быть положительным числом.";
             return;
         }
 
@@ -470,10 +479,10 @@
         {
             await SessionService.AddCoGmForOwnerAsync(
                 GroupId,
-                "Telegram",
-                coGmModel.TelegramId.Value.ToString(),
+                CoGmPlatform,
+                coGmExternalUserId,
                 coGmModel.DisplayName,
-                coGmModel.TelegramUsername);
+                coGmModel.ExternalUsername);
 
             coGmModel = new();
             successMessage = "Co-GM добавлен.";
@@ -493,15 +502,17 @@
         }
     }
 
-    private async Task RemoveCoGm(string coGmExternalUserId)
+    private async Task RemoveCoGm(WebGroupManager manager)
     {
         errorMessage = null;
         successMessage = null;
-        removingCoGmId = coGmExternalUserId;
+        removingCoGmId = ManagerKey(manager);
+        var platform = ManagerPlatform(manager);
+        var coGmExternalUserId = ManagerExternalUserId(manager);
 
         try
         {
-            await SessionService.RemoveCoGmForOwnerAsync(GroupId, "Telegram", coGmExternalUserId);
+            await SessionService.RemoveCoGmForOwnerAsync(GroupId, platform, coGmExternalUserId);
             successMessage = "Co-GM удалён.";
             await LoadSessions();
         }
@@ -834,22 +845,51 @@
 
     private bool IsTemplateBusy(CampaignTemplateUsageModel template) => processingTemplateId == template.Id;
 
+    private string CoGmPlatform =>
+        string.IsNullOrWhiteSpace(groupManagement?.Group.Platform)
+            ? "Telegram"
+            : groupManagement.Group.Platform;
+
+    private string CoGmIdLabel => $"{CoGmPlatform} ID co-GM";
+
     private string CurrentUserRole =>
-        groupManagement?.Managers.FirstOrDefault(manager => manager.ExternalUserId == externalUserId)?.Role
+        groupManagement?.Managers.FirstOrDefault(manager =>
+            string.Equals(ManagerPlatform(manager), currentPlatform, StringComparison.OrdinalIgnoreCase) &&
+            ManagerExternalUserId(manager) == externalUserId)?.Role
         ?? GroupManagerRoleExtensions.CoGmValue;
 
     private static string FormatRole(string role) =>
         GroupManagerRoleExtensions.FromDatabaseValue(role).ToDisplayName();
 
-    private static string FormatManager(WebGroupManager manager)
+    private string FormatManager(WebGroupManager manager)
     {
-        var username = string.IsNullOrWhiteSpace(manager.TelegramUsername)
-            ? manager.TelegramId.ToString(System.Globalization.CultureInfo.InvariantCulture)
-            : "@" + manager.TelegramUsername;
+        var username = string.IsNullOrWhiteSpace(manager.ExternalUsername)
+            ? manager.TelegramUsername
+            : manager.ExternalUsername;
+        var identity = string.IsNullOrWhiteSpace(username)
+            ? $"{ManagerPlatform(manager)} {ManagerExternalUserId(manager)}"
+            : "@" + username.TrimStart('@');
 
-        return $"{FormatRole(manager.Role)} · {manager.DisplayName} · {username}";
+        return $"{FormatRole(manager.Role)} · {manager.DisplayName} · {identity}";
     }
 
+    private string ManagerPlatform(WebGroupManager manager) =>
+        string.IsNullOrWhiteSpace(manager.Platform) ? CoGmPlatform : manager.Platform;
+
+    private static string ManagerExternalUserId(WebGroupManager manager) =>
+        string.IsNullOrWhiteSpace(manager.ExternalUserId)
+            ? manager.TelegramId.ToString(System.Globalization.CultureInfo.InvariantCulture)
+            : manager.ExternalUserId;
+
+    private string ManagerKey(WebGroupManager manager) =>
+        $"{ManagerPlatform(manager)}:{ManagerExternalUserId(manager)}";
+
+    private static bool IsValidPlatformUserId(string platform, string externalUserId) =>
+        string.Equals(platform, "Telegram", StringComparison.OrdinalIgnoreCase)
+            ? long.TryParse(externalUserId, out var telegramId) && telegramId > 0
+            : !string.Equals(platform, "Discord", StringComparison.OrdinalIgnoreCase) ||
+              (ulong.TryParse(externalUserId, out var platformId) && platformId > 0);
+
     private static int InferIntervalDays(IReadOnlyList<WebSession> orderedSessions)
     {
         if (orderedSessions.Count < 2)
@@ -944,8 +984,8 @@
 
     private sealed class CoGmEditModel
     {
-        public long? TelegramId { get; set; }
+        public string ExternalUserId { get; set; } = "";
         public string DisplayName { get; set; } = "";
-        public string? TelegramUsername { get; set; }
+        public string? ExternalUsername { get; set; }
     }
 }
diff --git a/src/GmRelay.Web/Services/SessionService.cs b/src/GmRelay.Web/Services/SessionService.cs
index 73d3224..1cde71b 100644
--- a/src/GmRelay.Web/Services/SessionService.cs
+++ b/src/GmRelay.Web/Services/SessionService.cs
@@ -28,6 +28,7 @@ public sealed record WebGameGroup(
 public sealed record WebGroupManager(
     long TelegramId,
     string? ExternalUserId,
+    string? Platform,
     string DisplayName,
     string? TelegramUsername,
     string? ExternalUsername,
@@ -35,7 +36,17 @@ public sealed record WebGroupManager(
     DateTime AddedAt)
 {
     public WebGroupManager(long telegramId, string displayName, string? telegramUsername, string role, DateTime addedAt)
-        : this(telegramId, null, displayName, telegramUsername, null, role, addedAt) { }
+        : this(telegramId, null, null, displayName, telegramUsername, null, role, addedAt) { }
+
+    public WebGroupManager(
+        long telegramId,
+        string? externalUserId,
+        string displayName,
+        string? telegramUsername,
+        string? externalUsername,
+        string role,
+        DateTime addedAt)
+        : this(telegramId, externalUserId, null, displayName, telegramUsername, externalUsername, role, addedAt) { }
 }
 
 public sealed record WebGroupManagement(
@@ -215,8 +226,13 @@ public sealed class SessionService(
         await using var conn = await dataSource.OpenConnectionAsync();
         return (await conn.QueryAsync<WebGroupManager>(
             """
-            SELECT COALESCE(p.external_user_id::BIGINT, 0) AS TelegramId,
+            SELECT CASE
+                       WHEN p.platform = 'Telegram' AND p.external_user_id ~ '^[0-9]+$'
+                           THEN p.external_user_id::BIGINT
+                       ELSE 0
+                   END AS TelegramId,
                    p.external_user_id AS ExternalUserId,
+                   p.platform AS Platform,
                    p.display_name AS DisplayName,
                    p.external_username AS TelegramUsername,
                    p.external_username AS ExternalUsername,
diff --git a/tests/GmRelay.Bot.Tests/Discord/DiscordNewSessionHandlerTests.cs b/tests/GmRelay.Bot.Tests/Discord/DiscordNewSessionHandlerTests.cs
index 437dc82..53c70fd 100644
--- a/tests/GmRelay.Bot.Tests/Discord/DiscordNewSessionHandlerTests.cs
+++ b/tests/GmRelay.Bot.Tests/Discord/DiscordNewSessionHandlerTests.cs
@@ -115,6 +115,18 @@ public sealed class DiscordNewSessionHandlerTests
         Assert.Contains("UnauthorizedAccessException", source, StringComparison.Ordinal);
     }
 
+    [Fact]
+    public void Handler_ShouldLoadCoGmPermissionsFromDiscordPlayers()
+    {
+        var repoRoot = GetRepoRoot();
+        var handlerPath = Path.Combine(repoRoot, "src", "GmRelay.DiscordBot", "Features", "Sessions", "DiscordNewSessionHandler.cs");
+        var source = File.ReadAllText(handlerPath);
+
+        Assert.Matches(
+            @"QueryAsync<ulong>[\s\S]*JOIN players p ON p\.id = gm\.player_id[\s\S]*p\.platform = 'Discord'[\s\S]*g\.external_group_id = @GuildId",
+            source);
+    }
+
     [Fact]
     public void Handler_ShouldBePlatformNeutral()
     {
diff --git a/tests/GmRelay.Bot.Tests/Web/GroupDetailsSourceTests.cs b/tests/GmRelay.Bot.Tests/Web/GroupDetailsSourceTests.cs
new file mode 100644
index 0000000..0871503
--- /dev/null
+++ b/tests/GmRelay.Bot.Tests/Web/GroupDetailsSourceTests.cs
@@ -0,0 +1,35 @@
+namespace GmRelay.Bot.Tests.Web;
+
+public sealed class GroupDetailsSourceTests
+{
+    [Fact]
+    public async Task GroupDetails_ShouldManageCoGmUsingGroupPlatform()
+    {
+        var source = await ReadRepositoryFileAsync("src/GmRelay.Web/Components/Pages/GroupDetails.razor");
+
+        Assert.Contains("CoGmPlatform", source, StringComparison.Ordinal);
+        Assert.Contains("@CoGmIdLabel", source, StringComparison.Ordinal);
+        Assert.Contains("coGmModel.ExternalUserId", source, StringComparison.Ordinal);
+        Assert.Matches(@"SessionService\.AddCoGmForOwnerAsync\(\s*GroupId,\s*CoGmPlatform,\s*coGmExternalUserId", source);
+        Assert.Matches(@"SessionService\.RemoveCoGmForOwnerAsync\(GroupId,\s*platform,\s*coGmExternalUserId\)", source);
+        Assert.DoesNotContain("Telegram ID co-GM", source, StringComparison.Ordinal);
+        Assert.DoesNotContain("SessionService.RemoveCoGmForOwnerAsync(GroupId, \"Telegram\"", source, StringComparison.Ordinal);
+    }
+
+    private static async Task<string> ReadRepositoryFileAsync(string relativePath)
+    {
+        var directory = new DirectoryInfo(AppContext.BaseDirectory);
+        while (directory is not null)
+        {
+            var candidate = Path.Combine(directory.FullName, relativePath);
+            if (File.Exists(candidate))
+            {
+                return await File.ReadAllTextAsync(candidate);
+            }
+
+            directory = directory.Parent;
+        }
+
+        throw new FileNotFoundException($"Could not locate repository file '{relativePath}'.");
+    }
+}