jev-harness (ismaelsoilet)
Zero-dependency System One decision harness: 5 semantic gates saving frontier AI agent tokens on trivial errors & doom loops. Python + TypeScript + Rust. MCP-compatible.
How it uses Jev
⚡ Jev Harness: The Token Optimizer & Decision Gate for AI Coding Agents
Highlights
- 🛡️ Zero External Dependencies: Built entirely with Python's standard library ( urllib.request , dataclasses , json ). No pip bloat; measured offline CLI cold start 80–100 ms, in-…
- 🔌 Universal MCP Server: Exposes Jev decision tools over stdio ( jev-mcp ) for Cursor, Claude Desktop, Antigravity, Windsurf, Zed, and OpenCode.
- 🚦 UNIX Philosophy Compliant: Standard exit codes ( 0 for safe/skip llm, 1 for abort/logic defect, 2 for syntax error) allow clean pipe composition: pytest jev-harness test-gate .
- 🔄 Resilient Provider Fallback: retryable failures ( 429 , 5xx , timeouts, network errors) retry with capped exponential backoff and honor Retry-After ; after the attempts, the de…
- 👻 Shadow Mode: --shadow (or "shadow": true in .jev.json ) decides and reports [SHADOW] would exit N while always exiting 0 , so the pipeline keeps running while you measure the g…
- 🧾 Audit trail & self-diagnosis: jev-harness doctor checks config, credentials (fingerprint only), model origin, limits, state permissions, receipts/cache and the git hook — every…
Getting started
1. Installation Across Ecosystems Available on all three major package registries with zero external runtime dependencies:
- Languages
- Python 50% · Rust 28% · TypeScript 20% · Shell 1%
- License
- MIT
- Latest release
- Release v0.2.0
- Last activity
- Sep 2026
- Added
- 2026-09-22
- Stars at snapshot
- 6
- Status
- Community listing
Source: community catalog. Details and metrics reflect the published community snapshot and are not a performance endorsement. Documentation details extracted from GitHub · the README · the project website.