jev-layer
Portable decision layer for agent harnesses: Jev picks from host-supplied capabilities while the host keeps permissions and execution.
Overview
jev-layer lets an agent harness ask for a bounded choice without handing over control. The host sends a request and the candidate capabilities it already allows to jev_route; Jev returns a bounded recommendation; the host checks it against its own registry and permissions, decides whether to execute, and can record the outcome against the original correlation ID with jev_record_execution for offline replay. Jev never executes anything, and if it is disabled, unavailable, invalid or inconclusive, control returns to the host's normal path.
Other tools include jev_supervise for bounded work-state judgements (continue, verify, retry, finish or escalate, decided by the host) and jev_model_route for advisory model-profile selection. Providers can be a deterministic offline demo, OpenRouter Decisions or TypeSafe. It integrates with Hermes, OMP, Codex and generic MCP, requires Node 20+ with no mandatory runtime dependencies, and has docs in English, Russian and Chinese.
What the decision model decides
| Type | Question | Answers |
|---|---|---|
| Choice | Which host-supplied capability fits this request? | — |
| Choice | What is the state of the work (continue, verify, retry, finish, escalate)? | continue · verify · retry · finish · escalate |
| Choice | Which declared model profile should the next call use? | — |
How it works
- Install and add a harness adapter
- Host sends a request with allowed candidates
- Jev recommends; host validates and executes
- Record outcomes and replay offline
Strengths
- Host keeps full control
- Offline demo provider for CI
- Receipts and replay
Caveats
- Recommendations only; host integration required
Getting started
`npm install --global jev-layer`, `jev install --project /path`, `jev add generic --project /path`, `jev doctor --project /path`.At a glance
- Type
- Project
- Status
- beta
- Language
- TypeScript
- Runtime
- Node 20+ CLI and stdio MCP server
- Has code
- yes
- Has tests
- yes
- License
- MIT
Use cases and integrations
How curated lists describe it
Portable System-1 decision layer for agent harnesses with host-owned routing, receipts, replay, and fail-open integrations.
logicrw/awesome-jev-projectsPortable System-1 decision layer for agent harnesses with host-owned routing, receipts, replay, and fail-open integrations.
hellogumbo/awesome-jev
Frequently asked questions
Does Jev execute anything?
No, it only recommends from candidates the host supplies.
What if Jev is unavailable?
Control returns to the host's normal path.
Can I test offline?
Yes, with the deterministic demo provider.
Related projects
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