Fix bugs: MeshMessage position field, summary loading, Google system prompt, import placement, cleanup timer

- 1a: Declare _position as proper dataclass field with field(default=None, init=False)
  so hasattr() check isn't needed and the attribute always exists
- 1b: Load persisted conversation summaries from DB into memory cache on startup
  via new _load_summaries() method called after backend creation
- 1c: Use Gemini's system_instruction parameter on GenerativeModel instead of
  only prepending to first message, so system prompt persists across all turns
- 1d: Move 'import os' from line 198 to top of main.py with other imports
- 1e: Replace unreliable modulo-based cleanup timer with _last_cleanup timestamp
  comparison that won't miss hours due to async sleep jitter

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

meshai/backends/google_backend.py

@@ -162,6 +162,12 @@ class GoogleBackend(LLMBackend):
                 )
 
         try:
+            # Create model with system instruction for persistent system prompt
+            model = genai.GenerativeModel(
+                self.config.model,
+                system_instruction=enhanced_system if enhanced_system else None,
+            )
+
             # Convert messages to Gemini format
             # Gemini uses "user" and "model" roles
             history = []
@@ -170,15 +176,11 @@ class GoogleBackend(LLMBackend):
                 history.append({"role": role, "parts": [msg["content"]]})
 
             # Start chat with history
-            chat = self._model.start_chat(history=history)
+            chat = model.start_chat(history=history)
 
             # Get the last user message
             last_message = final_messages[-1]["content"] if final_messages else ""
 
-            # Prepend system prompt to first message if needed
-            if enhanced_system and not history:
-                last_message = f"{enhanced_system}\n\n{last_message}"
-
             # Generate response
             response = await chat.send_message_async(
                 last_message,

meshai/connector.py

@@ -2,7 +2,7 @@
 
 import asyncio
 import logging
-from dataclasses import dataclass
+from dataclasses import dataclass, field
 from typing import Callable, Optional
 
 import meshtastic
@@ -26,13 +26,12 @@ class MeshMessage:
     channel: int  # Channel index
     is_dm: bool  # True if direct message to us
     packet: dict  # Raw packet for additional data
+    _position: Optional[tuple[float, float]] = field(default=None, repr=False, init=False)
 
     @property
     def sender_position(self) -> Optional[tuple[float, float]]:
         """Get sender's GPS position if available (lat, lon)."""
-        # Position comes from node info, not the message itself
+        return self._position
-        # This will be populated by the connector if available
-        return self._position if hasattr(self, "_position") else None
 
 
 class MeshConnector:

meshai/main.py

@@ -3,6 +3,7 @@
 import argparse
 import asyncio
 import logging
+import os
 import signal
 import sys
 import time
@@ -18,6 +19,7 @@ from .commands.status import set_start_time
 from .config import Config, load_config
 from .connector import MeshConnector, MeshMessage
 from .history import ConversationHistory
+from .memory import ConversationSummary
 from .responder import Responder
 from .router import MessageRouter, RouteType
 
@@ -37,6 +39,7 @@ class MeshAI:
         self.responder: Optional[Responder] = None
         self._running = False
         self._loop: Optional[asyncio.AbstractEventLoop] = None
+        self._last_cleanup: float = 0.0
 
     async def start(self) -> None:
         """Start the bot."""
@@ -52,6 +55,7 @@ class MeshAI:
 
         self._running = True
         self._loop = asyncio.get_event_loop()
+        self._last_cleanup = time.time()
 
         # Write PID file
         self._write_pid()
@@ -63,8 +67,9 @@ class MeshAI:
             await asyncio.sleep(1)
 
             # Periodic cleanup
-            if int(time.time()) % 3600 == 0:  # Every hour
+            if time.time() - self._last_cleanup >= 3600:
                 await self.history.cleanup_expired()
+                self._last_cleanup = time.time()
 
     async def stop(self) -> None:
         """Stop the bot."""
@@ -121,6 +126,9 @@ class MeshAI:
                 self.config.llm, api_key, window_size, summarize_threshold
             )
 
+        # Load persisted summaries into memory cache
+        await self._load_summaries()
+
         # Meshtastic connector
         self.connector = MeshConnector(self.config.connection)
 
@@ -183,6 +191,40 @@ class MeshAI:
         except Exception as e:
             logger.error(f"Error handling message: {e}", exc_info=True)
 
+    async def _load_summaries(self) -> None:
+        """Load persisted summaries from database into memory cache."""
+        memory = self.llm.get_memory()
+        if not memory:
+            return
+
+        if not self.history or not self.history._db:
+            return
+
+        try:
+            async with self.history._lock:
+                cursor = await self.history._db.execute(
+                    "SELECT user_id, summary, message_count, updated_at "
+                    "FROM conversation_summaries"
+                )
+                rows = await cursor.fetchall()
+
+            loaded = 0
+            for row in rows:
+                user_id, summary_text, message_count, updated_at = row
+                summary = ConversationSummary(
+                    summary=summary_text,
+                    last_updated=updated_at,
+                    message_count=message_count,
+                )
+                memory.load_summary(user_id, summary)
+                loaded += 1
+
+            if loaded:
+                logger.info(f"Loaded {loaded} conversation summaries from database")
+
+        except Exception as e:
+            logger.warning(f"Failed to load summaries from database: {e}")
+
     def _write_pid(self) -> None:
         """Write PID file."""
         pid_file = Path("/tmp/meshai.pid")
@@ -195,9 +237,6 @@ class MeshAI:
             pid_file.unlink()
 
 
-import os
-
-
 def setup_logging(verbose: bool = False) -> None:
     """Configure logging."""
     level = logging.DEBUG if verbose else logging.INFO