Last updated: September 2026
Jev for social media
Jev is TypeSafe AI first System One model. You hand it a piece of text and a set of typed questions, and it hands back typed answers with probabilities. TypeSafe describes those probabilities as calibrated and puts response time in the hundreds of milliseconds, and we have not verified either. It cannot write a single word, and that constraint is the whole point.
Which makes it very good at one job social media is full of: deciding things about text, at a volume no human and no language model budget can keep up with.
Three layers, and Jev is only one of them
Almost every confused take about Jev comes from expecting it to replace a language model. It does not. A working social pipeline has three distinct jobs, and they want three different tools.
The full build is written up in build an AI social media agent.
What a call looks like
One request, several questions, all answered in the same parallel pass. Asking for six things costs the same round trip as asking for one.
import { TypeSafeClient, score, noul } from '@typesafe-ai/sdk';
const client = new TypeSafeClient();
const { answers } = await client.systemOne({
state: { post: draft, platform: 'X (Twitter)' },
questions: {
hook: score('How well does the opening line stop someone mid scroll?', [
'No hook. Opens with context or a greeting.',
'Functional. States the subject plainly.',
'Strong. Creates tension or surprise in the first line.',
]),
bait: noul('This post explicitly asks the reader for likes, reposts or follows.'),
},
});
answers.hook.score; // probability-weighted float across the rubric
answers.hook.confidence; // how certain the model is
answers.bait.noul; // a float 0 to 1. Nouls have no confidence field.The detail most write-ups get wrong
A Noul returns only its float. There is no confidence field on a Noul, because the float already is the probability. Choice and Score do return confidence. The primitives reference has the exact response shape for all three.This runs in production
OpenTweet free post scorer sends every draft you type to Jev as one request carrying seven questions: four Score rubrics for reach, hook, clarity and specificity, and three Nouls for AI-slop, engagement bait and toxicity. It runs one request per draft. TypeSafe publishes Jev's end-to-end response time, and we do not publish our own timings. No account needed, and you can watch the confidence band move as you edit.
Start here
What to use it for
Ten jobs on social media that are decisions about text.
Build it
Wiring judgment to something that acts.
Compare it
Honest comparisons, including the cases where Jev is the wrong answer.
When not to reach for Jev
- You need words back. Drafting, rewriting, summarising, replying. Jev emits no text at all.
- Your content is images or video. Jev is text only, which rules out a lot of real social moderation.
- You make a handful of decisions a day. At low volume the integration effort costs more than the inference it saves.
- You need a defensible audit trail about a person. A probability is a filter, not evidence.
Frequently asked questions
What is Jev?
Jev is TypeSafe AI first System One model, released on 15 September 2026. You send it a state and a map of typed questions, and it returns typed answers with probabilities that TypeSafe describes as calibrated, in one parallel pass. It never generates text, so it is not a chatbot and not a replacement for a language model.
Is Jev an LLM?
No. A language model decodes text one token at a time. Jev answers a fixed schema of questions in parallel and returns numbers and labels only. That is why its output tokens are free, and TypeSafe puts its end-to-end response time in hundreds of milliseconds rather than seconds.
What is Jev good for on social media?
Judgment at volume. Scoring a draft before you publish it, classifying inbound replies and mentions, filtering a feed, flagging rage bait or spam, and ranking variants of a post against each other. All of these are decisions about text, which is exactly what Jev does.
Can Jev write my posts?
No. Jev cannot emit text at all. Writing is a job for a language model. A working pipeline uses both: a language model drafts, Jev judges, and something else publishes.
How much does Jev cost?
TypeSafe's published price is $0.042 per million input tokens, with free output and no free tier. On that pricing, a short social post scored on a handful of questions costs a few millionths of a dollar.
Is Jev used in a real product?
Yes. The free Will It Go Viral post scorer is built on Jev, where seven Jev questions grade every draft as you type. It is not used for generation anywhere, because Jev cannot generate.
Jev decides. OpenTweet publishes.
One API and an MCP server for X, Bluesky and LinkedIn, so the judgment your agent makes turns into something that actually posts. From $11.99 a month.
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