Send custom gameover command to UCI engine at game end

engine.py

@@ -121,3 +121,18 @@
             print("Engine could not be terminated cleanly.")
 
         self.transport.close()
+
+    async def send_gameover(self, result: str) -> None:
+        """Send a custom 'gameover <result>' UCI extension command to the engine.
+    
+        result should be one of: '1-0', '0-1', '1/2-1/2'
+        This is a non-standard extension — engines that don't handle it will
+        simply ignore the unknown command.
+        """
+        try:
+            # python-chess exposes the asyncio SubprocessTransport on the protocol.
+            # Pipe 0 is stdin of the engine process.
+            stdin_transport = self.transport.get_pipe_transport(0)
+            stdin_transport.write(f"gameover {result}\n".encode())
+        except Exception:
+            pass  # Never crash BotLi because of a custom engine extension

game.py

@@ -34,6 +34,8 @@ async def run(self) -> None:
         if info.state["status"] != "started":
             self._print_result_message(info.state, lichess_game, info)
             await chatter.send_goodbyes()
+            if uci_result := self._get_uci_result(info.state):
+                await lichess_game.engine.send_gameover(uci_result)
             await lichess_game.close()
             return
 
@@ -85,6 +87,8 @@ async def run(self) -> None:
 
                 self._print_result_message(event, lichess_game, info)
                 await chatter.send_goodbyes()
+                if uci_result := self._get_uci_result(event):
+                    await lichess_game.engine.send_gameover(uci_result)
                 break
 
             if has_updated:
@@ -186,3 +190,18 @@ def _print_result_message(
         message = " • ".join([info.id_str, opponents_str, message])
 
         print(f"{message}\n{123 * '‾'}")
+
+    @staticmethod
+    def _get_uci_result(game_state: dict[str, Any]) -> str | None:
+        """Convert a Lichess game_state dict to a UCI result string.
+        Returns None for aborted games (no meaningful result to report).
+        """
+        winner = game_state.get("winner")
+        status = game_state.get("status", "")
+        if status in {"aborted", "noStart", "unknownFinish"}:
+            return None
+        if winner == "white":
+            return "1-0"
+        if winner == "black":
+            return "0-1"
+        return "1/2-1/2"