At a glance
The philosophical difference
Letta is a framework for building stateful agents. Agents persist memory across conversations, and memory is versioned like a filesystem. It answers the question “how do agents keep state?” Worlds answers a different question: “how do agents know what is true?” It is a context engine that stores and retrieves verified facts. It does not run agents, manage tools, or schedule work. The two are complementary rather than competing. An agent built with Letta can call Worlds when it needs a fact it can trust.When Worlds fits
- You need a source of truth that any agent can query, regardless of the framework that runs it.
- Facts must survive across agent restarts, model swaps, and application rewrites.
- You want SPARQL-verifiable answers, not retrieved text.
When Worlds does not fit
- You want a complete agent stack in one system: memory, tool execution, and conversation state.
- You need long-running agent workflows with built-in persistence.