Expose speaker playback and play_tone tool via MCP

mcp_server.py

@@ -217,6 +217,18 @@ class MCPServer:
                                 },
                                 "required": ["code"]
                             }
+                        },
+                        {
+                            "name": "play_tone",
+                            "description": "Play a pure sine wave tone/beep on the board speaker.",
+                            "inputSchema": {
+                                "type": "object",
+                                "properties": {
+                                    "frequency": {"type": "integer", "description": "Frequency of the tone in Hz (e.g. 440 for A4, default 440)", "default": 440},
+                                    "duration_ms": {"type": "integer", "description": "Duration of the tone in milliseconds (default 1000)", "default": 1000},
+                                    "volume": {"type": "integer", "description": "Volume of the tone from 0 to 100 (default 50)", "default": 50}
+                                }
+                            }
                         }
                     ]
                 },
@@ -407,5 +419,19 @@ class MCPServer:
                 return output
             return f"Execution Succeeded. Console output:\n{output}"
             
+        elif name == "play_tone":
+            freq = int(args.get("frequency", 440))
+            duration = int(args.get("duration_ms", 1000))
+            vol = int(args.get("volume", 50))
+            
+            # Limit duration to prevent blocking the main loop for too long
+            duration = max(50, min(5000, duration))
+            freq = max(50, min(10000, freq))
+            vol = max(0, min(100, vol))
+            
+            from audio_util import play_tone
+            play_tone(frequency=freq, duration_ms=duration, volume=vol)
+            return f"Played tone of {freq}Hz for {duration}ms at volume {vol}."
+            
         else:
             raise ValueError(f"Unknown tool: {name}")