""" title: Chat Context Clipper (that works :-) author: open-webui & bgeneto (several improvements) author_url: https://github.com/bgeneto/open-webui-functions/blob/main/chat_context_clipper_function.py funding_url: https://github.com/open-webui version: 0.1.2 description: A filter that truncates chat history to retain the latest n-th user and assistant messages while always keeping the system prompt and also first message pair (if desired). It ensures that the first message (after the prompt if any) is a user message (Anthropic requirement). It also offers a user valve to set the number of messages to retain, which overrides the global setting. """ from typing import Dict, List, Optional, Union from pydantic import BaseModel, Field DEBUG = False def get_first_user_message( data: List[Dict[str, Union[str, dict]]] ) -> Optional[Dict[str, str]]: """ Returns the first user message in the given data. Args: data (list): A list of dictionaries containing role and content. Returns: dict: The first user message. """ for message in data: if message["role"] == "user": return message return None def get_first_assistant_message( data: List[Dict[str, Union[str, dict]]] ) -> Optional[Dict[str, str]]: """ Returns the first assistant message in the given data. Args: data (list): A list of dictionaries containing role and content. Returns: dict: The first assistant message. """ for message in data: if message["role"] == "assistant": return message return None class Filter: class Valves(BaseModel): priority: int = Field( default=0, description="Priority level for the filter operations" ) n_last_messages: int = Field( default=4, description="Number of last messages to keep" ) keep_first: bool = Field( default=False, description="Always Keep the first user message and assistant answer", ) pass class UserValves(BaseModel): n_last_messages: int = Field( default=4, description="Number of last chat messages to keep in the assistant memory", ) pass def __init__(self): self.valves = self.Valves() self.user_valves = self.UserValves() pass def inlet(self, body: dict, __user__: Optional[dict] = None) -> dict: messages = body["messages"] if DEBUG: print("Original messages length:", len(messages)) # Ensure we always keep the system prompt system_prompt = next( (message for message in messages if message.get("role") == "system"), None ) # Always keep the first user message... first_user_message = get_first_user_message(messages) # ...and the first assistant message first_assistant_message = get_first_assistant_message(messages) # Collect the last n_last_messages from user and assistant n_last_messages = int( self.user_valves.n_last_messages if self.user_valves.n_last_messages else self.valves.n_last_messages ) # double (user and assistant) number of messages to keep and... # ...also add one more pair of messages to account for keeping the first n_last_messages = 2 * n_last_messages if self.valves.keep_first: n_last_messages = n_last_messages + 2 recent_messages = [ message for message in messages if message["role"] in ["user", "assistant"] ][-n_last_messages:] # Construct the new message list by appending the system prompt first (if any) new_messages = [] if system_prompt: new_messages.append(system_prompt) # Check if we need to append the first couple of messages if self.valves.keep_first: if first_user_message: new_messages.append(first_user_message) if first_assistant_message: new_messages.append(first_assistant_message) # Ensure the sequence is system -> user -> assistant if ( recent_messages and recent_messages[0]["role"] == "user" and len(recent_messages) > 1 ): if recent_messages[1]["role"] == "user": recent_messages.pop(0) # remove/pop assistant message if it the first if ( recent_messages and recent_messages[0]["role"] == "assistant" and len(recent_messages) > 1 ): recent_messages.pop(0) if len(recent_messages) > 1 and recent_messages[0]["role"] == "assistant": recent_messages.pop(0) new_messages.extend(recent_messages) if DEBUG: print("Clipped messages length:", len(new_messages)) # Update body messages body["messages"] = new_messages return body