Merge pull request #770 from tnfssc/fix/context-window-finale

Author: tnfssc

backend/agentpress/thread_manager.py

@@ -240,14 +240,87 @@ def _compress_messages(self, messages: List[Dict[str, Any]], llm_model: str, max
         logger.info(f"_compress_messages: {uncompressed_total_token_count} -> {compressed_token_count}") # Log the token compression for debugging later
 
         if max_iterations <= 0:
-            logger.warning(f"_compress_messages: Max iterations reached")
+            logger.warning(f"_compress_messages: Max iterations reached, omitting messages")
+            result = self._compress_messages_by_omitting_messages(messages, llm_model, max_tokens)
             return result
 
         if (compressed_token_count > max_tokens):
             logger.warning(f"Further token compression is needed: {compressed_token_count} > {max_tokens}")
             result = self._compress_messages(messages, llm_model, max_tokens, int(token_threshold / 2), max_iterations - 1)
 
         return result
+    
+    def _compress_messages_by_omitting_messages(
+            self, 
+            messages: List[Dict[str, Any]], 
+            llm_model: str, 
+            max_tokens: Optional[int] = 41000,
+            removal_batch_size: int = 10,
+            min_messages_to_keep: int = 10
+        ) -> List[Dict[str, Any]]:
+        """Compress the messages by omitting messages from the middle.
+        
+        Args:
+            messages: List of messages to compress
+            llm_model: Model name for token counting
+            max_tokens: Maximum allowed tokens
+            removal_batch_size: Number of messages to remove per iteration
+            min_messages_to_keep: Minimum number of messages to preserve
+        """
+        if not messages:
+            return messages
+            
+        result = messages
+        result = self._remove_meta_messages(result)
+
+        # Early exit if no compression needed
+        initial_token_count = token_counter(model=llm_model, messages=result)
+        max_allowed_tokens = max_tokens or (100 * 1000)
+        
+        if initial_token_count <= max_allowed_tokens:
+            return result
+
+        # Separate system message (assumed to be first) from conversation messages
+        system_message = messages[0] if messages and messages[0].get('role') == 'system' else None
+        conversation_messages = result[1:] if system_message else result
+        
+        safety_limit = 500
+        current_token_count = initial_token_count
+        
+        while current_token_count > max_allowed_tokens and safety_limit > 0:
+            safety_limit -= 1
+            
+            if len(conversation_messages) <= min_messages_to_keep:
+                logger.warning(f"Cannot compress further: only {len(conversation_messages)} messages remain (min: {min_messages_to_keep})")
+                break
+
+            # Calculate removal strategy based on current message count
+            if len(conversation_messages) > (removal_batch_size * 2):
+                # Remove from middle, keeping recent and early context
+                middle_start = len(conversation_messages) // 2 - (removal_batch_size // 2)
+                middle_end = middle_start + removal_batch_size
+                conversation_messages = conversation_messages[:middle_start] + conversation_messages[middle_end:]
+            else:
+                # Remove from earlier messages, preserving recent context
+                messages_to_remove = min(removal_batch_size, len(conversation_messages) // 2)
+                if messages_to_remove > 0:
+                    conversation_messages = conversation_messages[messages_to_remove:]
+                else:
+                    # Can't remove any more messages
+                    break
+
+            # Recalculate token count
+            messages_to_count = ([system_message] + conversation_messages) if system_message else conversation_messages
+            current_token_count = token_counter(model=llm_model, messages=messages_to_count)
+
+        # Prepare final result
+        final_messages = ([system_message] + conversation_messages) if system_message else conversation_messages
+        final_token_count = token_counter(model=llm_model, messages=final_messages)
+        
+        logger.info(f"_compress_messages_by_omitting_messages: {initial_token_count} -> {final_token_count} tokens ({len(messages)} -> {len(final_messages)} messages)")
+            
+        return final_messages
+
 
     def add_tool(self, tool_class: Type[Tool], function_names: Optional[List[str]] = None, **kwargs):
         """Add a tool to the ThreadManager."""