Jev Use
Claude Code / Codex / pi plugin that hands agent steps needing no text output to Jev (TypeSafe's judgment model) — measured p50 ~230 ms and ~$0.02 per 1,000 judgments, with…
Install
npx -y jev-use installclaude mcp add jev-use -- npx -y jev-use install{
"mcpServers": {
"jev-use": {
"command": "npx",
"args": [
"-y",
"jev-use",
"install"
]
}
}
}Install command taken from the project's README or registry entry. Always review code before running it.
README excerpt
Read full README on GitHub →jev-use
English | 简体中文
The best way for Claude Code, Codex, and pi to work with Jev: hand the tasks that need no text output to Jev — faster steps, fewer tokens, tasks done sooner and better.
It makes the LLM and Jev true collaborators: when content needs to be written, the LLM takes over; when a step just needs a fast decision, Jev executes it.
Demos — real runs, 1× speed
Every demo is a rerunnable script in bench/examples/; all numbers, methodology, variance and caveats: bench/RESULTS.md · third-party measurements: docs/evidence.md.
Install
npx -y jev-use install # wires Claude Code, Codex, and pi — whichever it finds
Set one key in the environment your agent runs in (JEV_BACKEND=mock for
a keyless dry run):
| Provider | Env var |
|---|---|
| TypeSafe direct | TYPESAFE_API_KEY |
| OpenRouter | OPENROUTER_API_KEY |
| Vercel AI Gateway | AI_GATEWAY_API_KEY |
npx -y jev-use doctor checks the wiring. Judged state goes to the
provider you configure; JEV_BACKEND=mock stays local. Plugin form with
the routing skill and the PreToolUse gate:
harness/claude-code ·
harness/codex.
Use as a library
npm i jev-use — zero runtime dependencies on the judgment path:
import { Jev, check, pick, rate } from "jev-use";
const jev = new Jev();
const { answers } = await jev.judge(state, {
next: pick("Next action?", { merge: "all green", rerun: "looks flaky", hold: "needs attention" }),
risk: rate("How risky?", ["routine", "worth a look", "incident"]),
passed: check("Did the run fully succeed?"),
});
// answers.next → { answer: "merge", confidence: 0.93, confidenceFrom: "reported", escalate: false }
Anything Jev can't or shouldn't decide comes back with escalate: true
and a typed reason. Tools, verdict shape, escalation contract, CLI:
docs/reference.md.
Small enough to read
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