What it is
A deterministic-first decision layer for AI coding agents (OpenCode, Claude Code, Cursor, and others), triaging test failures, breaking doom loops, vetoing completion, governing reasoning effort, and routing models. Callable as CLI, MCP server, git/CI hook, and typed SDKs in Python, TypeScript, and Rust.
How it uses Jev
Jev makes typed decisions on the failure log or plan state: test-gate classifies the failure and sets skip_llm from a confidence threshold; abort-check scores dead-end probability to abort trajectories; route picks a model tier; verify checks evidence against criteria; reasoning-effort modulates effort. Results drive exit codes, JSON output, and SDK return values.
Primitives:choicescorenoul
Technique worth stealing
Gate trivial failures with a calibrated confidence threshold so frontier LLM calls are skipped deterministically.
Try it
npm test | jev-harness test-gate
Evidence
Each line is one question put to Jev about the README. ≥ 0.60 reads as yes, ≤ 0.40 as no; in between Jev is not making a call.
- Jev-centricyes0.93
- Shows a System One patternyes0.83
- Handles uncertaintyno0.10
- Measuredunclear0.45
- Runnableyes0.86
- Worth recommendingno0.35
- Model replicano0.26
- Problem scopescore on a 0–2 scale1.52
- About Jevyes0.97
Signals by Jev jev-1.13.0, card written by DeepSeek V4.1 Flash from the README on 23 Sept 2026.