What it is
fx is a coding agent CLI written in Zig: a small native binary, open source (Apache-2.0), model-agnostic, and embeddable as a harness in larger systems. Its interface stays closer to a Unix shell than an IDE.
How it uses Jev
The README does not describe how Jev is used. It only notes that fx ships a typesafe_permission_reviewer builtin so the agent's permission decisions run through Jev rather than an LLM call; no state, questions, or code usage are documented.
Try it
curl -fsSL https://fx.sh/setup.sh | bash
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-centricno0.14
- Shows a System One patternunclear0.45
- Handles uncertaintyno0.06
- Measuredno0.04
- Runnableyes0.98
- Worth recommendingno0.22
- Model replicano0.15
- Problem scopescore on a 0–2 scale1.80
- About Jevyes0.74
Signals by Jev jev-1.13.0, card written by DeepSeek V4.1 Flash from the README on 20 Sept 2026.