March 6, 2025

Message Modification API

We’ve added a new API endpoint that allows you to modify existing messages in an agent’s conversation history. This feature is particularly useful for editing message history to refine agent behavior without starting a new conversation.

1 from letta_client import Letta, UpdateSystemMessage
2 client = Letta(
3     token="YOUR_API_KEY",
4 )
5 client.agents.messages.modify(
6     agent_id="AGENT_ID",
7     message_id="MESSAGE_ID",
8     request=UpdateSystemMessage(
9         content="The agent should prioritize brevity in responses.",
10     ),
11 )