diff --git a/gateway/platforms/base.py b/gateway/platforms/base.py
index c12d417b3..1e7436188 100644
--- a/gateway/platforms/base.py
+++ b/gateway/platforms/base.py
@@ -413,11 +413,12 @@ class BasePlatformAdapter(ABC):
         """
         return SendResult(success=False, error="Not supported")
 
-    async def send_typing(self, chat_id: str) -> None:
+    async def send_typing(self, chat_id: str, metadata=None) -> None:
         """
         Send a typing indicator.
         
         Override in subclasses if the platform supports it.
+        metadata: optional dict with platform-specific context (e.g. thread_id for Slack).
         """
         pass
     
@@ -620,7 +621,7 @@ class BasePlatformAdapter(ABC):
         
         return media, cleaned
     
-    async def _keep_typing(self, chat_id: str, interval: float = 2.0) -> None:
+    async def _keep_typing(self, chat_id: str, interval: float = 2.0, metadata=None) -> None:
         """
         Continuously send typing indicator until cancelled.
         
@@ -629,7 +630,7 @@ class BasePlatformAdapter(ABC):
         """
         try:
             while True:
-                await self.send_typing(chat_id)
+                await self.send_typing(chat_id, metadata=metadata)
                 await asyncio.sleep(interval)
         except asyncio.CancelledError:
             pass  # Normal cancellation when handler completes
diff --git a/gateway/platforms/signal.py b/gateway/platforms/signal.py
index 3404bbb94..d2212ae88 100644
--- a/gateway/platforms/signal.py
+++ b/gateway/platforms/signal.py
@@ -580,7 +580,7 @@ class SignalAdapter(BasePlatformAdapter):
             return SendResult(success=True)
         return SendResult(success=False, error="RPC send failed")
 
-    async def send_typing(self, chat_id: str) -> None:
+    async def send_typing(self, chat_id: str, metadata=None) -> None:
         """Send a typing indicator."""
         params: Dict[str, Any] = {
             "account": self.account,