Letta

Letta

Letta (formerly MemGPT) is an open-source platform for building stateful agents with persistent memory. Unlike stateless LLM calls, Letta agents remember past interactions, accumulate knowledge over time, and can self-edit their own memory — enabling agents that genuinely improve with use.

Key Features

• Persistent memory layers: Core memory (always in context), archival memory (vector-searched), and recall memory (conversation history)
• Self-editing memory: Agents can autonomously read and write their own memory banks via tool calls
• Agent server: REST API + Python/TypeScript SDKs for integrating into any application
• Multi-agent orchestration: Agents can spawn sub-agents and communicate via a shared message bus
• Model-agnostic: Works with any OpenAI-compatible provider (GPT, Claude, Llama, Mistral)
• Sleeper agents: Agents persist between sessions with full state restoration

Quick Start

pip install letta
letta server  # starts the agent server on :8283

from letta import create_client

client = create_client()
agent = client.create_agent(name="my-assistant")

response = client.send_message(
    agent_id=agent.id,
    message="Remember that I prefer concise answers.",
    role="user"
)

Add to ai-supply

npx ai-supply add letta-stateful-agents

Curated mirror of the open-source Letta (Apache-2.0). Get it from the source.