Official
TypeSafe JavaScript SDK
Official TypeScript/JavaScript client for System One requests, including Choice, Score, and Noul builders with inferred answer types.
Independent Jev resource
Learn, build, and explore Jev.
Practical guides, a cost calculator, reusable decision templates, and a curated directory for TypeSafe AI's Jev decision model.
Four paths
Use JevHub for the part you need.
Start with the concept, estimate cost, copy a bounded decision pattern, or inspect the surrounding ecosystem.
Learn
What is Jev?
Understand typed decisions, probabilities, and where Jev fits.
Calculate
Estimate usage cost
Turn token volume and request volume into monthly cost.
Build
Copy decision templates
Start from closed Choice, Score, and Noul patterns.
Explore
Browse the ecosystem
Find SDKs, integrations, agent tools, and community projects.
What Jev is good at
Decisions that software can consume directly.
Jev is shaped for bounded decisions: classify, route, score, or estimate a yes/no probability. It is not a free-form text generator.
Classify
Choose one label from a defined set.
Route
Pick the next allowed path in a workflow.
Score
Map state onto an ordered rubric.
Check
Estimate whether a yes/no condition is supported.
Featured templates
Start from a bounded task, not a blank prompt.
choicenoul
Refund Detection
Identify whether a support case is primarily asking for money back, without turning classification into refund authorization.
choicenoulscore
Lead Qualification
Separate real sales opportunities from partnerships, support requests, spam, and unclear inbound messages.
choicenoul
Agent Router
Choose the next allowed agent or tool from a constrained graph without treating the model's choice as authorization.
noulchoice
Task Completion
Verify an agent's claim of completion against tool evidence and the observed final state.
Ecosystem preview
Jev is already showing up in real developer tooling.
JevHub curates a small set of projects and checks each original repository before listing it.
Official
TypeSafe Python SDK
Official Python client for TypeSafe's System One API, useful when Jev decisions live in Python services or data pipelines.
Official
System One Adapter (Python)
Official adapter that exposes a TypeSafeClient-compatible interface backed by chat-model providers for side-by-side workflow comparisons.
Official
TypeSafe Agent Skills
Official agent skill material for using System One primitives and evaluation patterns from coding agents such as Codex and Claude Code.
SDKs
advocaat
A compact community client that wraps TypeSafe/Jev decisions behind a type-oriented developer API.
SDKs
typesafe-ai (Rust)
Community Rust client for TypeSafe AI with typed request/response handling for System One workloads.
Separate store
JevHub's content site and store stay independent.
The Store is an external JevHub property. Learning, templates, and ecosystem content remain available here whether or not the Store changes.