How is this different from RAG?
RAG retrieves text by similarity and pastes it into a prompt. Beliefs maintains a probabilistic model of what your agent thinks is true. RAG can tell you "here is a relevant paragraph." Beliefs can tell you "this claim is 85% confident, based on 3 sources, and contradicted by one." They solve different problems. You can use both.
How is this different from a vector store?
A vector store recalls snippets. Beliefs models uncertainty, tracks provenance, detects contradictions, and decays stale evidence. A vector store answers "what text is related to this query." Beliefs answers "what does the agent currently believe, how strongly, and why."
Do I need to understand probability to use it?
No. The SDK handles the math. Confidence is a number between 0 and 1. That is enough for most use cases. If you want the distributions, entropy formulas, and Bayesian updates, they are documented in Internals > Math.
Can I use beliefs without an adapter?
Yes. The core before/after loop works with any agent framework:
1const context = await beliefs.before(input)
2const result = await yourAgent.run({ prompt: context.prompt })
3await beliefs.after(result)Adapters handle framework-specific plumbing for you, but the core SDK is framework-agnostic.
What happens when two claims conflict?
The fusion engine detects conflicts, resolves them by trust weight, and keeps both in the trace. Nothing is silently discarded. You can query contradictions from beliefs.read() and decide how to handle them in your agent logic.
Does performance degrade with many claims?
The SDK handles pruning and decay. Stale claims lose weight over time through temporal decay. The system self-manages so old, low-confidence claims do not accumulate indefinitely.
Do beliefs persist across sessions?
Yes. The hosted backend persists beliefs automatically. An API key is required — there is no local-only mode in the current release. Local persistence adapters are planned for a future version.
Does this replace my agent framework?
No. Beliefs wraps your loop. It does not replace it. Use it with Claude Agent SDK, Vercel AI SDK, LangGraph, or any custom agent loop. If you have a loop, beliefs works with it.
What if I only have a single-turn agent?
Beliefs is designed for multi-turn, multi-source scenarios. For single-turn Q&A, memory or retrieval is typically sufficient. Beliefs matters when agents run multiple turns on the same topic, accumulate information that might conflict, or need to coordinate across agents.
Where do I get help?
- Beta support channel. Direct access to the engineering team.
- GitHub. Open an issue on the beliefs repo.
- Beta access. Request access if you are not yet in the program.