fix: string results (tool contract) + is_async=True for plugin tool handlers

adapter.py

@@ -11,6 +11,7 @@ including both outbound messaging and realtime WebSocket connections.
 
 from __future__ import annotations
 
+import json
 import random
 
 # Put the vendored dependencies for THIS platform on sys.path before importing
@@ -3614,10 +3615,10 @@ async def _handle_chatto_send_dm(args: dict) -> dict:
     message = args.get("message") or ""
 
     if not message:
-        return {"success": False, "error": "message is required"}
+        return json.dumps({"success": False, "error": "message is required"})
 
     if not user_login and not user_id:
-        return {"success": False, "error": "Exactly one of user_login or user_id is required"}
+        return json.dumps({"success": False, "error": "Exactly one of user_login or user_id is required"})
 
     # --- Read config: explicit args first, then fall back to resolved config ---
     explicit_base_url = args.get("base_url") or ""
@@ -3637,12 +3638,12 @@ async def _handle_chatto_send_dm(args: dict) -> dict:
     else:
         base_url = "https://chat.chatto.run"
     if not token:
-        return {"success": False, "error": "Chatto token not configured"}
+        return json.dumps({"success": False, "error": "Chatto token not configured"})
 
     try:
         client = ChattoClient(base_url=base_url, token=token)
     except Exception as exc:
-        return {"success": False, "error": f"Failed to create Chatto client: {exc}"}
+        return json.dumps({"success": False, "error": f"Failed to create Chatto client: {exc}"})
 
     try:
         # 1. Resolve the target user
@@ -3653,15 +3654,15 @@ async def _handle_chatto_send_dm(args: dict) -> dict:
 
         member = member_data.get("member")
         if not member:
-            return {"success": False, "error": f"User not found (login={user_login or user_id})"}
+            return json.dumps({"success": False, "error": f"User not found (login={user_login or user_id})"})
 
         target_user = member.get("user")
         if not target_user:
-            return {"success": False, "error": "User record missing in member data"}
+            return json.dumps({"success": False, "error": "User record missing in member data"})
 
         target_user_id = target_user.get("id")
         if not target_user_id:
-            return {"success": False, "error": "User has no ID"}
+            return json.dumps({"success": False, "error": "User has no ID"})
 
         target_login = target_user.get("login", user_login)
 
@@ -3696,19 +3697,19 @@ async def _handle_chatto_send_dm(args: dict) -> dict:
             msg = await client.post_message(dm_room_id, chunk)
             message_ids.append(msg.id)
 
-        return {
+        return json.dumps({
             "success": True,
             "dm_room_id": dm_room_id,
             "recipient": target_login,
             "recipient_user_id": target_user_id,
             "message_ids": message_ids,
             "chunks_sent": len(message_ids),
-        }
+        })
 
     except ChattoAuthError as exc:
-        return {"success": False, "error": f"Authentication error: {exc}"}
+        return json.dumps({"success": False, "error": f"Authentication error: {exc}"})
     except ChattoError as exc:
-        return {"success": False, "error": f"Chatto API error: {exc}"}
+        return json.dumps({"success": False, "error": f"Chatto API error: {exc}"})
     finally:
         try:
             await client.close()
@@ -3723,10 +3724,10 @@ async def _handle_chatto_send_room(args: dict) -> dict:
     message = args.get("message") or ""
 
     if not message:
-        return {"success": False, "error": "message is required"}
+        return json.dumps({"success": False, "error": "message is required"})
 
     if not room_id and not room_name:
-        return {"success": False, "error": "Exactly one of room_id or room_name is required"}
+        return json.dumps({"success": False, "error": "Exactly one of room_id or room_name is required"})
 
     # --- Read config: explicit args first, then fall back to resolved config ---
     explicit_token = args.get("token") or ""
@@ -3742,12 +3743,12 @@ async def _handle_chatto_send_room(args: dict) -> dict:
     if not base_url:
         base_url = _resolved_chatto_config.base_url.value or "https://chat.chatto.run" if _resolved_chatto_config is not None else "https://chat.chatto.run"
     if not token:
-        return {"success": False, "error": "Chatto token not configured"}
+        return json.dumps({"success": False, "error": "Chatto token not configured"})
 
     try:
         client = ChattoClient(base_url=base_url, token=token)
     except Exception as exc:
-        return {"success": False, "error": f"Failed to create Chatto client: {exc}"}
+        return json.dumps({"success": False, "error": f"Failed to create Chatto client: {exc}"})
 
     try:
         # 1. Resolve the target room
@@ -3761,14 +3762,14 @@ async def _handle_chatto_send_room(args: dict) -> dict:
                     found = rws
                     break
             if not found or not found.room:
-                return {"success": False, "error": f"Room not found: {room_name}"}
+                return json.dumps({"success": False, "error": f"Room not found: {room_name}"})
             room_id = found.room.id
             room_label = found.room.name
         else:
             # Verify room exists
             rws = await client.get_room(room_id)
             if not rws or not rws.room:
-                return {"success": False, "error": f"Room not found: {room_id}"}
+                return json.dumps({"success": False, "error": f"Room not found: {room_id}"})
             room_label = rws.room.name
 
         # 2. Post the message
@@ -3781,18 +3782,18 @@ async def _handle_chatto_send_room(args: dict) -> dict:
             msg = await client.post_message(room_id, chunk)
             message_ids.append(msg.id)
 
-        return {
+        return json.dumps({
             "success": True,
             "room_id": room_id,
             "room_name": room_label,
             "message_ids": message_ids,
             "chunks_sent": len(message_ids),
-        }
+        })
 
     except ChattoAuthError as exc:
-        return {"success": False, "error": f"Authentication error: {exc}"}
+        return json.dumps({"success": False, "error": f"Authentication error: {exc}"})
     except ChattoError as exc:
-        return {"success": False, "error": f"Chatto API error: {exc}"}
+        return json.dumps({"success": False, "error": f"Chatto API error: {exc}"})
     finally:
         try:
             await client.close()
@@ -3810,6 +3811,7 @@ def register(ctx) -> None:
         toolset="chatto-platform",
         schema=CHATTO_SEND_DM_SCHEMA,
         handler=_handle_chatto_send_dm,
+        is_async=True,
         description=CHATTO_SEND_DM_SCHEMA["description"],
     )
     ctx.register_tool(
@@ -3817,6 +3819,7 @@ def register(ctx) -> None:
         toolset="chatto-platform",
         schema=CHATTO_SEND_ROOM_SCHEMA,
         handler=_handle_chatto_send_room,
+        is_async=True,
         description=CHATTO_SEND_ROOM_SCHEMA["description"],
     )