use-jev

use-jev is a skill for Claude Code, Codex from OpenHands/extensions. It costs 25 tokens per session (721 once invoked), scanned A, original, MIT.

A guide for using Jev, a classifier that answers typed questions about text or application state with choices, scores, or yes/no probabilities. Its results can support routing, ranking, extraction, and verification.

In plain words
What is it for?
Use it to route requests, rank or score items, detect conditions such as refund requests, check citations, and integrate the Python, JavaScript, or HTTP interface.
Why use it?
It provides a structured way to turn uncertain text or state judgments into data that software can use, while making confidence visible.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to route requests, rank or score items, detect conditions such as refund requests, check citations, and integrate the Python, JavaScript, or HTTP interface.

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Install with agentmods
npx agentmods add skills/openhands/extensions/use-jev
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add OpenHands/extensions --skill use-jev
Clone the repo
git clone --depth 1 https://github.com/OpenHands/extensions

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for use-jev

README.md
[![agentmods](https://agentmods.dev/badge/skills/openhands/extensions/use-jev/github.svg)](https://agentmods.dev/skills/openhands/extensions/use-jev)
Your own site
<a href="https://agentmods.dev/skills/openhands/extensions/use-jev"><img src="https://agentmods.dev/badge/skills/openhands/extensions/use-jev/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for use-jev

Your own site · 80×15
<a href="https://agentmods.dev/skills/openhands/extensions/use-jev"><img src="https://agentmods.dev/badge/skills/openhands/extensions/use-jev.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 721 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00025 $0.00721
Opus 5.5 $0.00010 $0.00288
Sonnet 5.5 $0.00005 $0.00144
Haiku 4.5 $0.00003 $0.00072

Measured 15d ago against content hash 56bd6d2c1003, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

use-jev scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 15d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/use-jev/SKILL.md · 67 lines

What it actually says

Jev is a newly released general classifier. Give it text or application state and typed questions; it returns decisions and probabilities your code can use for routing, ranking, extraction, or verification.

Read the upstream llms.txt to find current documentation, then follow the pages relevant to the task:

Choice, Score, and Noul

Primitive Example use Result
Choice Route a support request to a team One option, option probabilities, and confidence
Score Rate a bug's impact Probability-weighted position on ordered levels, plus confidence
Noul Check whether a refund is requested Probability of yes; 0.5 means uncertainty, not medium intensity

Install typesafe-sdk and check that JEV_API_KEY is set in the environment, otherwise ask the user to provide it. This Python example asks one question of each type in a single call:

import os

from typesafe_sdk import Choice, Noul, Score, TypeSafeClient

with TypeSafeClient(api_key=os.environ["JEV_API_KEY"]) as client:
    result = client.system_one(
        state={"ticket": "PDF export fails, but CSV works. Please refund this month."},
        questions={
            "team": Choice(
                instructions="Which team should handle the main issue in the ticket?",
                criteria={"billing": "Charges and payments",
                          "technical": "Broken product features", "other": "Neither"},
            ),
            "impact": Score(
                instructions="How much does the reported bug affect functionality?",
                criteria=["Cosmetic only", "Feature broken; workaround available",
                          "Work blocked; no workaround available"],
            ),
            "refund": Noul(instructions="Does the ticket explicitly request a refund?"),
        },
    )

print(result.choices["team"].choice)
print(result.scores["impact"].score)
print(result.nouls["refund"].noul)
Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 15d ago First seen · 67 lines · 25 tokens per session scan A 56bd6d2c1003

Subscribe to this mod's changes

use-jev is a skill published in the GitHub repository OpenHands/extensions (167 stars, last pushed today), licensed MIT. It adds 25 tokens to every session and 721 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-10-02.

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