fix(discord): add auto-thread fallback path

gateway/platforms/discord.py

@@ -2034,9 +2034,25 @@ async def _auto_create_thread(self, message: 'DiscordMessage') -> Optional[Any]:
         try:
             thread = await message.create_thread(name=thread_name, auto_archive_duration=1440)
             return thread
-        except Exception as e:
-            logger.warning("[%s] Auto-thread creation failed: %s", self.name, e)
-            return None
+        except Exception as direct_error:
+            display_name = getattr(getattr(message, "author", None), "display_name", None) or "unknown user"
+            reason = f"Auto-threaded from mention by {display_name}"
+            try:
+                seed_msg = await message.channel.send(f"\U0001f9f5 Thread created by Hermes: **{thread_name}**")
+                thread = await seed_msg.create_thread(
+                    name=thread_name,
+                    auto_archive_duration=1440,
+                    reason=reason,
+                )
+                return thread
+            except Exception as fallback_error:
+                logger.warning(
+                    "[%s] Auto-thread creation failed. Direct error: %s. Fallback error: %s",
+                    self.name,
+                    direct_error,
+                    fallback_error,
+                )
+                return None
 
     async def send_exec_approval(
         self, chat_id: str, command: str, session_key: str,

tests/gateway/test_discord_slash_commands.py

@@ -289,6 +289,8 @@ async def test_auto_create_thread_uses_message_content_as_name(adapter):
     message = SimpleNamespace(
         content="Hello world, how are you?",
         create_thread=AsyncMock(return_value=thread),
+        channel=SimpleNamespace(send=AsyncMock()),
+        author=SimpleNamespace(display_name="Jezza"),
     )
 
     result = await adapter._auto_create_thread(message)
@@ -307,6 +309,8 @@ async def test_auto_create_thread_truncates_long_names(adapter):
     message = SimpleNamespace(
         content=long_text,
         create_thread=AsyncMock(return_value=thread),
+        channel=SimpleNamespace(send=AsyncMock()),
+        author=SimpleNamespace(display_name="Jezza"),
     )
 
     result = await adapter._auto_create_thread(message)
@@ -318,10 +322,33 @@ async def test_auto_create_thread_truncates_long_names(adapter):
 
 
 @pytest.mark.asyncio
-async def test_auto_create_thread_returns_none_on_failure(adapter):
+async def test_auto_create_thread_falls_back_to_seed_message(adapter):
+    thread = SimpleNamespace(id=555, name="Hello")
+    seed_message = SimpleNamespace(create_thread=AsyncMock(return_value=thread))
     message = SimpleNamespace(
         content="Hello",
         create_thread=AsyncMock(side_effect=RuntimeError("no perms")),
+        channel=SimpleNamespace(send=AsyncMock(return_value=seed_message)),
+        author=SimpleNamespace(display_name="Jezza"),
+    )
+
+    result = await adapter._auto_create_thread(message)
+    assert result is thread
+    message.channel.send.assert_awaited_once_with("🧵 Thread created by Hermes: **Hello**")
+    seed_message.create_thread.assert_awaited_once_with(
+        name="Hello",
+        auto_archive_duration=1440,
+        reason="Auto-threaded from mention by Jezza",
+    )
+
+
+@pytest.mark.asyncio
+async def test_auto_create_thread_returns_none_when_direct_and_fallback_fail(adapter):
+    message = SimpleNamespace(
+        content="Hello",
+        create_thread=AsyncMock(side_effect=RuntimeError("no perms")),
+        channel=SimpleNamespace(send=AsyncMock(side_effect=RuntimeError("send failed"))),
+        author=SimpleNamespace(display_name="Jezza"),
     )
 
     result = await adapter._auto_create_thread(message)