jev-layer

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Portable System-1 decision layer for agent harnesses: host-owned routing over candidate capabilities, receipts/replay, optional supervision judgments, and fail-open integrations (Hermes, OMP, Codex, generic MCP).

At a glance	Details
Source	Source
Maintainer	typakon4. Independently curated; this entry is not an upstream submission or endorsement.
Format	Node.js package jev-layer 0.1.0 — CLI (jev), stdio MCP server, harness installers, and offline demo provider. Published on npm.
Requirements	Node.js 20+. Live TypeSafe mode needs TYPESAFE_API_KEY (or OpenRouter Decisions with OPENROUTER_API_KEY). Default demo provider is offline and deterministic.
License	MIT.
Disclosure	AI-assisted catalog review; no affiliation with the maintainer. Listing is not an endorsement. Source and offline npm test inspected; live TypeSafe/OpenRouter provider calls were not run.

When to use

Use it when an agent harness should ask a bounded chooser which capability to try next, while the host keeps permissions, execution, retries, and final results. Prefer jev-router / Jev Model Router when the goal is coding-CLI model selection rather than capability routing with receipts. Prefer toolgate / jev-guard when you need tool-call firewalls rather than a portable decision MCP.

How it works

jev_route selects one capability id from a host-supplied candidate set (advisory; the host validates). jev_record_execution joins host results to a correlation_id for JSONL replay under .jev/replay/. jev_supervise returns bounded work-state judgments mapped by host policy. Providers: deterministic demo, OpenRouter Decisions (typesafe/jev-1.13), or direct TypeSafe (https://api.typesafe.ai/v1/systemone, jev-latest). See docs/PROVIDERS.md and docs/AGENT-IMPLEMENTATION.md.

Get started

npm install --global jev-layer
# or from source at the reviewed tip:
git clone https://github.com/typakon4/jev-layer.git
cd jev-layer
git checkout 05d3cdf1f1d925d7c0bf0749caebc232f749c613
npm install
npm test
jev doctor --project /path/to/workspace

jev add generic --project … (or Hermes/OMP/Codex) wires harness config. Live TypeSafe/OpenRouter modes send states and Choice questions to the configured provider and can incur charges; this listing used the offline test suite only.

Examples and demos

• Offline npm test (92 tests passed on the review host).
• examples/ request fixtures and provider docs.
• Replay evaluation via npm run replay:evaluate (not re-run beyond unit tests here).

Limits and data handling

Jev never executes a selected capability—the host must validate ids and permissions. Fail-open and supervision defaults are intentional; misconfigured hosts can still act wrongly. Remote providers receive route/supervise state text. Upstream latency/accuracy claims were not independently measured.

Review and maintenance

Reviewed on 2026-09-20 at commit 05d3cdf: 0.1.0, MIT. AI-assisted source review of README, LICENSE, provider docs, and CLI/MCP surfaces. Ran npm test (92 pass). No live TypeSafe calls.

Related: jev-router, toolgate, jev-mcp.