diff --git a/ChatTwo/AutoTellTabsService.cs b/ChatTwo/AutoTellTabsService.cs
new file mode 100644
index 0000000..f4c5d22
--- /dev/null
+++ b/ChatTwo/AutoTellTabsService.cs
@@ -0,0 +1,89 @@
+using System;
+using System.Linq;
+
+namespace ChatTwo;
+
+// Hellion Chat — Auto-Tell-Tabs.
+//
+// Spawns a session-only tab per /tell partner so a club greeter can track
+// multiple parallel conversations without losing context. Subscribes to
+// MessageManager.MessageProcessed for live tells and to ClientState.Logout
+// for the cleanup pass; everything else hangs off these two entry points.
+//
+// See spec: Hellion Chat Auto-Tell-Tabs Spec (Obsidian vault).
+internal sealed class AutoTellTabsService : IDisposable
+{
+    private readonly Plugin _plugin;
+    private readonly MessageManager _messageManager;
+    private readonly MessageStore _store;
+    private readonly object _tempTabsLock = new();
+
+    private bool _initialized;
+
+    internal AutoTellTabsService(Plugin plugin, MessageManager messageManager, MessageStore store)
+    {
+        _plugin = plugin;
+        _messageManager = messageManager;
+        _store = store;
+    }
+
+    internal int ActiveTempTabCount
+    {
+        get
+        {
+            lock (_tempTabsLock)
+            {
+                return Plugin.Config.Tabs.Count(t => t.IsTempTab);
+            }
+        }
+    }
+
+    internal void Initialize()
+    {
+        if (_initialized)
+        {
+            return;
+        }
+
+        _messageManager.MessageProcessed += HandleTell;
+        Plugin.ClientState.Logout += OnLogout;
+        _initialized = true;
+    }
+
+    public void Dispose()
+    {
+        if (!_initialized)
+        {
+            return;
+        }
+
+        Plugin.ClientState.Logout -= OnLogout;
+        _messageManager.MessageProcessed -= HandleTell;
+        _initialized = false;
+    }
+
+    internal void HandleTell(Message message)
+    {
+        // Stub — implemented in Task 8.
+    }
+
+    internal void MarkGreeted(Tab tab)
+    {
+        // Stub — implemented in Task 12.
+    }
+
+    internal void UnmarkGreeted(Tab tab)
+    {
+        // Stub — implemented in Task 12.
+    }
+
+    internal bool IsGreeted(Tab tab)
+    {
+        return tab.IsGreeted;
+    }
+
+    private void OnLogout(int type, int code)
+    {
+        // Stub — implemented in Task 10.
+    }
+}