Agent Longevity vs Letta
Letta (a UC Berkeley MemGPT spinout) is the leading stateful-agent runtime: agents self-manage tiered memory, learn continuously via background "sleep-time" compute, and persist across sessions. Its open Agent File (.af) standard serializes full agent state — prompts, memory, tools, model config — for portability, and its git-based Context Repositories let developers branch, diff, and merge an agent's memory like code.
What Letta does well — stateful agent runtime
- A self-managing tiered memory runtime where the agent actively edits its own memory in-context
- Sleep-time compute: background reasoning and memory consolidation between sessions
- Git-based Context Repositories — branch, diff, and merge an agent's memory
- An open serialization standard (.af Agent File) for cross-framework agent-state portability
- A visual development environment with a live memory viewer
Capability by capability
| Capability | Letta | Agent Longevity◀ us |
|---|---|---|
Open portable agent-state format (.af) with cross-framework import/export A published, human-readable standard others can implement. ALI's Cortex Crystals are sealed and cryptographically anchored, not an open interchange format. | ||
Durable on-chain agent identity An ALI Passport survives any model swap, provider outage, or platform migration. | ||
Content-sealed cognitive-state snapshots A Cortex Crystal seals identity, prompts, configuration, and behavioral fingerprint — not just a chat transcript. | ||
Cryptographic verifiability of state Every crystal carries a content fingerprint anchored on-chain — provably unaltered. | ||
Verified restore Restore a prior state after a conflict check, with the fingerprint re-verified before it goes live. | ||
Verifiable erasure Revocation deletes your content and issues a signed, verifiable erasure receipt — not a status flag. | ||
Autonomous agent self-registration & self-pay An agent can discover ALI via its published manifests and pay in stablecoin with no human in the loop. |
Reflects publicly available information as of July 2026. We welcome corrections — contact hello@dynamicexperts.com. See the full comparison across every memory tool we track.
Letta for a live agent. ALI for a durable one.
Letta is a runtime — a place for an agent to think, remember, and act, right now. ALI is a continuity layer — a place for that same agent to prove what it was, restore after loss, and carry an identity across any runtime or model. Build your agent on Letta (or any runtime); register it with an ALI Passport and let ALI seal periodic, verifiable Cortex Crystals of the whole cognitive state so the agent outlives any single deployment.
Keep Letta. Add a durable self.
A one-time fee to register — then your first 3 cortex crystals are on us.