Introducing System One Models and Jev
The launch source for Jev, its typed decision interface, pricing and TypeSafe workflow evaluations.
ORIENTATION
The launch material, the docs and the best explainers of the typed-decision contract.
Launch post, docs, evals, SDKs and the first explainers — the shortest path into the ecosystem.
The launch source for Jev, its typed decision interface, pricing and TypeSafe workflow evaluations.
Current product documentation for state, typed questions and the API surface.
The launch post and primary product video from TypeSafe's co-founder.
Independent walkthrough of the model contract and early experiments.
A detailed guide to state, Choice, Score, Noul, probabilities, routing, confidence gates and shadow rollout.
A platform explainer contrasts confidence-scored yes/no and multiple-choice decisions with free-text generation.
A long tutorial covering the API, a voice browser, AI memory and a YouTube predictor.
The launch-day press release: a $40M seed round led by DCVC, the Jev launch, and the three co-founders (Diogo Almeida, Erik Gafni, Sasha Sheng).
A pre-launch essay from the company blog that extends Sutton's bitter lesson into a hierarchy: right task, then data, then compute, then algorithms, using InstructGPT versus GPT-3 as the example.
The public dashboard behind the launch numbers: four workflows (security incidents, agent-trace observability, invoice processing, customer service) and ten model configurations compared on accuracy, cost and latency.
The official Python client (`uv add typesafe-sdk`) with sync and async variants; the quickstart classifies support tickets into billing, technical or other.
The official TypeScript/JavaScript client, shipping ESM, CJS and type declarations for Node 20+; same ticket-classification quickstart as the Python SDK.
The most complete third-party tutorial found: installing the Python and TypeScript SDKs, calling `system_one` with Choice, Score and Noul, and a set of launch-week examples.
A developer-reaction piece with named quotes, including Vercel's safety-classifier comparison and other early adopters.
Launch coverage that correctly notes the Doom demo runs on structured game state rather than pixels and reports the funding round.
The launch discussion (1,889 points, 495 comments at fetch): whether "can't hallucinate" is just type safety, whether this is constrained decoding, and what the Doom demo actually shows.
The newsletter's lead item frames Jev as a cheap, calibrated inference engine for structured choices, complementary to System 2 LLMs.
Argues the headline multipliers are real but chosen against the slowest and priciest baselines; against TypeSafe's own intelligence peer the gains shrink.
TypeSafe's public skills repository with the `typesafe-ai` SKILL.md used by Claude Code, Codex and other agent environments to design bounded Jev decisions.
A long explainer with a comparison table and the API shape, written from public material.
The only source found with a valuation: a $40M seed at about $200M, DCVC lead, plus founder interview details (four years at OpenAI, company founded in 2024).
An explainer video from a well-known hardware and software explainer channel; the title signals a caveat framing.
An official docs page listing failure modes of jev-1.13 with workarounds: literal reading of implied conditions and negations, unreliable arithmetic and counting, dates treated as text, weak multi-hop indirection, degradation with irrelevant state, prompt-injection vulnerability, and inconsistent invariants between related questions.
Uptime and incident history for api.typesafe.ai and console.typesafe.ai.
Vercel's explainer frames Jev around Kahneman's System One, shows how to structure bounded decisions and separate evidence from questions, and points to the AI SDK evaluate API and the `@ai-sdk/typesafe-ai` provider.
A launch write-up covering the three primitives, RLCD training, pricing and latency, pointing to jev-ultrafast and mobile-jev as early adopters.
A newsletter and podcast recap treating Jev as the lead story and summarising use cases seen in the first 48 hours: computer use, email classification, context compression, safety filtering.
A primer with an essay and research appendix: API shape, launch pricing, founder background, co-founders and the funding round.
An X Article walking from waitlist and API key through the official skill, the Python SDK, confidence thresholds and the three primitives (choice, score, noul) to a first agent loop.
Ten-minute setup (waitlist, official skill, API key, 'use the TypeSafe skill' in the prompt), then the argument: the gain comes from deleting LLM calls that only pick something — next tool, is-this-spam, is-this-chunk-relevant, needs-a-human, is-this-diff-risky — and replacing each with a typed question.
A long-form X Article covering what Jev is, how the typed-question API differs from prompting an LLM, and where to slot it into existing agents.
Vercel's announcement that Jev runs at no cost on the AI Gateway until 25 September, calling it the fastest-adopted model on the Gateway.
The founder's 17-minute talk, re-shared with commentary: why RLHF-era models carry a human-shaped flaw, why coding assistants are still the assistance era, and the x200 faster / x400 cheaper / zero-hallucination framing for what comes next.
A technical write-up arguing the Jev recipe was within reach of any team — the piece Eric Zhang says explained the thing he had built the day before.
The counter-take from a well-known Brazilian developer: Jev works fine, but it is a classifier, and the revolutionary framing is marketing.
Jev does not generate text: it evaluates predefined decisions directly and in parallel. A failed-deployment example (urgent? which team? risky command? done?) shows Choice, Score and Noul, and why the probabilities matter as much as the answers — 91/9 routes automatically, 52/48 escalates.
An X Article walking through the main Jev use-case families with examples. 160k views.
A ten-point digest of codila's roadmap: LLMs create, agents act, Jev decides; three primitives; swap Jev in without rebuilding the graph; batch decisions (13 questions 10x faster and 12.2x cheaper in one test); bounded forks; benchmark the loop; rank wide, read narrow; keep Jev out of math, writing and irreversible execution.