How do I roll out a risky rule without blocking traffic?

Use tags to select only relevant rules, such as cpq or devops, and set enforcement_mode audit for shadow evaluation plus on_failure fail_closed where a failed check must deny by default.

Where does this sit in an agent or deployment flow?

Put the proposed tool arguments, form payload, or diff through the engine first. For agents, return the BLOCKED result so the agent can self-correct; for backends, reject with 403; for CI, fail the pipeline.

Can it run through a gateway instead of TypeSafe directly?

Yes. Set TYPESAFE_API_KEY plus an optional gateway base URL, or pass a client with that base URL explicitly. The README documents Vercel AI Gateway use for caching and rate limiting.

What does day-to-day CLI and Python use look like?

Evaluate a JSON file or pipe state on stdin with jev-policy evaluate using policies and tags flags, or construct a YamlProvider plus JevPolicyEngine in Python and call evaluate with state and tags.

How do I define a policy?

A policy is a YAML entry with an id, description, a type of choice, noul or score, tags, and optional threshold and on_failure. For example NO_DESTRUCTIVE_COMMANDS is a choice with safe and destructive criteria tagged devops, while MAX_DISCOUNT_15 is a noul with threshold 0.90 and on_failure fail_closed.

What does an evaluation return?

A result object with a status and per-policy outcomes: the README shows MAX_DISCOUNT_15 returning passed false with mode block for a payload quoting a 30% discount. Tags narrow which rules run, such as cpq or devops, so unrelated policies do not fire.

What do I need to install, and can I swap the provider?

Clone the repository, run pip install -e . and install typesafe-sdk plus pyyaml, then set TYPESAFE_API_KEY. It ships a YamlProvider but is designed to integrate other sources such as Notion, CSV or Salesforce Custom Metadata.

CommunityJev Repos & SDKs

Jev Policy Engine

Python policy engine that defines Noul, Choice, and Score rules in YAML with tags, audit mode, and fail-closed handling, usable from a CLI or backend code.

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Stars: 3
Language: Python
License: MIT
Published by: Community
Author: BhavinM
Last verified: Oct 2026

BhavinM/jev-policy-engine

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Jev Policy Engine is the first universal Policy-as-Code SDK built for TypeSafe AI's Jev System One model. It allows RevOps, DevOps, and Security teams to define strict, deterministic AI governance rules in YAML, and execute them at high speed.

Forks: 0
Last pushed: Updated Sep 2026

Repo stats from the GitHub API, cached Oct 2026.

About this project

Jev Policy Engine is the first universal Policy-as-Code SDK built for TypeSafe AI's Jev System One model. It allows RevOps, DevOps, and Security teams to define strict, deterministic AI governance rules in YAML, and execute them at high speed. With this framework, you can decouple your business logic from your code, enabling non-developers to manage AI rules while keeping execution type-safe and deterministic. Policy-as-Code: Define Noul, Choice, and Score rules in clean YAML files.

Quoted from the project's README. Read the full README.

Tagscommunity github

Works forJev for Classification

Used inJev for Software & DevTools

Languages: Python

Highlights

Declares Choice, Noul, and Score policies in YAML with ids, descriptions, thresholds, enforcement mode, and tags.
Filters evaluation by tags so CPQ, finance, security, or devops rules run only for matching payloads.
Ships a CLI for piping diffs or JSON payloads plus a Python engine built around a YamlProvider.
Supports custom providers and gateway-backed clients for caching, rate limiting, and production deployment.

Watch out

Rules depend on live Jev judgments and provider credit; thresholds and enforcement behavior should be checked against the YAML in use. Copy reviewed against the repository README on 2026-10-04, not from running it.

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