Join the Beta
The beliefs SDK is in active beta. We're onboarding developers who are building agents that need to reason over time, tracking what they believe, how confident they are, and why things changed.
This is early software with a stable core. We ship weekly, we break things intentionally when it makes the API better, and we build alongside the people using it.
Ready to get started? Sign up for the beta → and we'll get you access within 48 hours.
What You Get
- Full SDK access.
beliefspackage with built-in adapters for Vercel AI SDK and Claude Agent SDK. - Founder Studio. The visual workspace for exploring and managing belief states.
- Direct line to the team. Private channel with engineering for support, feedback, and feature requests.
- Early influence. The API surface is not locked. Your feedback shapes what ships in 1.0.
What Beta Means
- The core patterns (
before/after, belief extraction, fusion) are stable and production-tested. - The API surface is evolving. We communicate breaking changes in advance and help you migrate.
- We ship updates weekly. You'll see things move fast.
- Some rough edges exist, and we want to hear about every one of them.
Who This Is For
- Agent builders who need structured state across multi-turn conversations
- Research and analysis teams building decision-support or investigation agents
- Developers who have outgrown simple memory and RAG and want traceable, probabilistic belief tracking
- Anyone curious about what it means to give agents a real epistemic substrate
Sign Up
Tell us what you're building and we'll get you set up.
You can also reach us directly at devs@thinkn.ai.