ModelSystem.One

September 19, 2026 · View on GitHub

Decision Models: AI that decides, not writes.

modelsystem.one is a curated catalog of System One / Decision Models — AI systems that return typed decisions (choice, score, boolean) with calibrated probabilities, instead of free-form chat text.

This repository is the public contribution surface for the project (issues, PRs, discussions). The website application source lives in a separate private repository.

What is a System One model?

Inspired by Kahneman’s Thinking, Fast and Slow:

	Traditional LLMs	Decision Models (System One)
Output	Free text	Typed decision + probability
Latency	Seconds	Milliseconds
Best for	Generation, reasoning	Classification, routing, scoring, guardrails

Today the public category is led by Jev (TypeSafe AI). This catalog exists to track every entrant as the category grows.

Site map

Path	Purpose
/	Home — category intro + featured model
/models	Catalog
/quadrant	Maturity × Capability evaluation
/learn	System 1 vs System 2 applied to AI
/guides	Integration tutorials
/news	Category news + RSS
/spec	Catalog inclusion criteria

Also available in Portuguese: modelsystem.one/pt-br.

How to contribute

We welcome:

New models that meet the catalog spec
Corrections to specs, pricing, status, or links
Documentation / learn / guide improvements (content proposals)
Bug reports about the public site

Start here:

Read CONTRIBUTING.md
Open an issue: New issue
Or submit a PR against this repo (content / meta changes)

Do not open PRs expecting the private application source to be here — this repo is for contributions and project meta only.

Inclusion criteria (summary)

Primary interface returns typed decisions (not free text)
Publicly available (GA, beta, or waitlist)
Minimum API documentation

Details: modelsystem.one/spec

Topics (GitHub)

Suggested repository topics for discoverability:

ai · system-one · decision-models · machine-learning · llm · catalog · typed-decisions · calibrated-probability · developer-tools · modelsystem

License

MIT — see LICENSE.
Site content and trademarks of third parties (e.g. TypeSafe, Jev) remain with their owners. ModelSystem.One is an independent catalog and is not affiliated with those vendors.