Jev in production › Model and agent routing

Jev Codex Router

Local proxy for Codex where Jev picks the model and thinking effort for each model call, including continuations after tools. About 60% lower list-price cost than a full-frontier baseline in a 237-turn historical replay (author).

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≈ −60 %measured against a baseline, as published by the source
Use
Model and agent routing
Industry
Developer tools
Form
Open-source tool
Stage
Beta
Plugs into
Codex
Listed
2026-09-19
Found via
github
Repository
0xNatoshi/jev-codex-router
Stars
273
Forks
46
Last push
2026-09-22
Language
JavaScript
License
MIT
Archived
yes

The README opens with

Per-call model routing for Codex, driven by Jev (TypeSafe System One).

Jev chooses a model and thinking effort together for each model call, including continuations after tools. Every route uses standard speed. The objective is sufficient capability for the next decision with no unnecessary quota consumption.

Historical simulation: ≈ −60 % vs full Astra on 237 turns under the old policy. This is not measured Codex quota saved, nor evidence for the current policy — protocol and limitations in BACKTEST.md. Installing with an AI agent? Hand it AGENTS.md.

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For the project's own README, linking back here:

Listed in Jev in production

Also used for model and agent routing