---
title: Agent Memory
subtitle: What is agent memory, and how does it work?
slug: guides/agents/memory
---

Agent memory is what enables AI agents to maintain persistent state, learn from interactions, and develop long-term relationships with users. Unlike traditional chatbots that treat each conversation as isolated, agents with sophisticated memory systems can build understanding over time.

## The MemGPT Approach to Memory

Letta is built by the creators of [MemGPT](https://arxiv.org/abs/2310.08560), a research paper that introduced the concept of an "LLM Operating System" for memory management. The base agent design in Letta is a MemGPT-style agent, which means it inherits the core principles of:

- **Self-editing memory**: Agents can modify their own memory using tools
- **Memory hierarchy**: Different types of memory for different purposes
- **Context window management**: Intelligent loading and unloading of information

## Types of Memory in Letta

Letta agents have access to multiple memory systems:

### Core Memory (In-Context)
Fast, always-accessible memory that stays in the agent's context window. This includes:
- **Persona**: The agent's personality and role
- **Human**: Information about the user
- **Custom memory blocks**: Additional structured information

### External Memory (Out-of-Context)
Long-term storage for large amounts of information:
- Conversation history beyond context limits (e.g. "recall memory")
- Vector databases for semantic search (e.g. "archival memory")
- Uploaded documents and files

## Why Agent Memory Matters

Effective memory management enables:

- **Personalization**: Agents remember user preferences and history
- **Learning**: Agents improve performance through accumulated experience
- **Context preservation**: Important information persists across conversations
- **Scalability**: Handle unlimited conversation length and data volume

## Memory Management in Practice

Letta provides multiple ways to work with agent memory:

- **Automatic management**: Agents intelligently decide what to remember
- **Manual control**: Developers can directly view and modify memory blocks
- **Shared memory**: Multiple agents can access common memory blocks
- **External data sources**: Connect agents to files, databases, and APIs

Memory blocks are the fundamental units of Letta's memory system - they can be modified by the agent itself, other agents, or developers through the API.