What Letta is
Letta (which grew out of the MemGPT research project) is a platform and open-source framework for building stateful agents, where the agent manages its own memory blocks and archival memory as part of its runtime.
What Auld is
Auld is a memory service. Your systems send time-stamped records; Auld extracts memories, reconciles changes into current state with history, and returns cited memories scoped to the viewer, over REST or MCP.
Differences in design
| Dimension | Letta | Auld |
|---|---|---|
| Layer | Agent runtime with built-in memory management | Memory service; you keep your agent framework |
| Who manages memory | The agent edits its own memory through tools | Your systems send records; Auld reconciles |
| Time and supersession | Check current docs | Validity intervals, history, asOf |
| Multi-tenant scoping | Per agent (see docs) | Identities, audiences, visibility |
| Open source | Yes | No |
How to choose
Choose Letta when
- You want the agent runtime and memory in one open-source system.
- You like the agent curating its own memory.
Choose Auld when
- You already have an agent framework and want memory as a service.
- Memory must come from business systems, not only conversations.
Evaluate and verify
Trade-offs depend on your data. Run the same test set against each option — the methodology page has a checklist — and confirm current capabilities in the official documentation.
Sources: Letta website · Letta on GitHub