Verdict

A programming language where decisions are the branches. Write ordinary logic — functions, loops, lists, strings — and wherever the program needs judgment, declare a decision and match on it. The checker makes sure every answer and "not sure" is handled before anything runs. At runtime each decision climbs a chain of models — a tiny one trained from your examples, Nodd, then Jet — until one is confident.

Website · Docs · Language reference · npm

decision moderate: choice "Is this comment ok to publish?" {
  ok: "harmless comment"
  spam: "ads, links, scams"
  toxic: "insults, harassment"
  examples from "comments.csv"
  tiers builtin -> jet
  threshold 0.85
}

fn action(comment: text) -> text {
  match moderate(comment) {
    ok => "publish"
    spam => "quarantine"
    toxic @ 0.9 => "hide"
    uncertain => "review"       // required — forgetting it is a compile error
  }
}

for c in read_lines("inbox.txt") { print("{action(c)}: {c}") }

npm install @quaedra/verdict     # Node 22+; the CLI is `verdict`
npx verdict run programs/hello.vd
npx verdict check programs/triage.vd

Language reference: docs/LANGUAGE.md · programs: programs/ · VS Code highlighting: editors/vscode

Also usable from TypeScript

The same runtime is a TypeScript library, for decisions inside an existing app:

import { at, choice, decide, jet, match } from "@quaedra/verdict";
import { builtinFromDisk } from "@quaedra/verdict/node";

export const Moderate = choice("comment_moderation", {
  instructions: "Is this comment ok to publish?",
  options: { ok: "harmless", spam: "ads, links, scams", toxic: "insults, harassment" },
  examples: [["Get 10k followers!!! cheap-followers.xyz", "spam"] /* … */],
  threshold: 0.85,
  backends: [builtinFromDisk(), jet()],          // escalation chain
});

const o = await decide(Moderate, comment);
match(o, {
  ok: () => publish(),
  spam: () => quarantine(),
  toxic: at(0.9, () => hide()),                  // guard: p(toxic) ≥ 0.9 or it's uncertain
  uncertain: () => review(),                     // required — forgetting it won't compile
});

What the type checker enforces

Mistake	Result
No uncertain arm	compile error
A label without an arm	compile error
An arm for a label that doesn't exist	compile error
An example labeled with a non-existent label	compile error
Arms returning different types	compile error

See tests/types.check.ts — each case is an @ts-expect-error.

Decision types (= Jet question types)

choice("topic", { instructions, options: { billing: "…", bug: "…" } })   // 2–255 options
noul("needs_human", { instructions })                                    // "yes" | "no"
score("urgency", { instructions, levels: { low: "…", high: "…" } })      // 2–10 ordered levels, + .score

decideAll(ticket, { topic, human: NeedsHuman, urgency: Urgency }) decides several on the same input; whatever is still unresolved goes to Jet in one request (Jet encodes the state once).

Tiers

Backend	Runs	Notes
builtin() / builtinFromDisk()	anywhere, no deps, < 1 ms	hashed n-gram logistic regression + temperature calibration, trained from examples
nodd(dir)	Node / browser	your Nodd export via @nodd/node (optional peer dep); uses Nodd's calibrated threshold and checks its labels match
jet({ url })	HTTP POST /v1/decide	jet-serve, the HF Space, or anything with the same format. $JET_URL, $JET_API_KEY
fn(name, …)	anywhere	rules, an LLM, a human queue

A tier that throws (Jet down) is logged in outcome.trail and skipped. If every tier is unsure, you get the most confident answer with certain: false → uncertain arm.

CLI

Loading a TypeScript module (.ts) needs tsx installed beside Verdict (npm install -D tsx); .vd programs and .js modules don't.

npx verdict check examples/moderation.ts
npx verdict build examples/moderation.ts          # train + calibrate builtin → .verdict/
npx verdict eval  examples/moderation.ts comment_moderation examples/data/comment_moderation.test.csv
npx verdict label examples/moderation.ts comment_moderation raw.txt --out labeled.csv   # teacher → Nodd CSV
npx verdict questions examples/triage.ts          # decisions as Jet questions (dry run)

Try it

npm install
npm run verdict -- build examples/moderation.ts && npm run verdict -- build examples/triage.ts
npm run demo        # starts an offline mock Jet unless JET_URL is set
npm test            # 29 runtime + language tests, plus type tests
npm run verdict -- run programs/triage.vd   # needs JET_URL (or run examples/mock-jet.ts)

PoC results on the 349 held-out comments (data: Nodd's synthetic comment_moderation set), builtin tier → mock Jet:

answered by	share	accuracy
builtin (692 KB, < 1 ms)	75%	96.6%
Jet (escalated)	23%	95.1%
uncertain → review	1.4%	—

Builtin alone is 87% accurate on everything; it keeps only what it's sure about. The mock Jet is a lookup over the dataset, not a model — rerun with a real Jet (JET_URL=…) for real numbers.

Design: docs/SPEC.md · Plan: docs/ROADMAP.md