# jev-use

Hands Jev the steps that need only a choice or a score, not prose. Your agent spends fewer tokens on routine forks.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 65
- Author: shitianfang
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/shitianfang/jev-use
- Updated: 2026-09-22
- HTML: https://affpapa.org/en/nevibecode/mcp/jev-use

## What it does

jev-use is an MCP server that routes no-text steps through Jev: yes/no, pick one of several options, rate on a scale. The LLM writes, Jev decides. Questions go out in one batched call, and each answer comes back with a confidence value and an `escalate` flag.

Inside are two MCP tools, a `Jev` client and a routing layer that drops some questions before they ever reach Jev. Whatever Jev should not decide returns to the agent with a typed reason. A `gate` checks shell commands: dangerous ones are denied with a reason, and credentials are stripped from a gated action before it is sent. The plugin form with routing rules and the PreToolUse hook lives in `harness/claude-code` and `harness/codex`.

You need a provider key in the environment your agent runs in: `TYPESAFE_API_KEY`, `OPENROUTER_API_KEY` or `AI_GATEWAY_API_KEY`. Without one the server will not run; `JEV_BACKEND=mock` gives a keyless dry run. Judged state goes to the provider you configure, and only mock stays local. Run `npx -y jev-use doctor` to check the wiring.

## Requirements
- Needs: Node.js (commands run via npx)

## Install

### Claude Code (native platform)

**Platform CLI**
```bash
claude mcp add jev-use -- npx -y jev-use
```

### Codex

**Platform CLI**
```bash
codex mcp add jev-use -- npx -y jev-use
```

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "jev-use": {
            "command": "npx",
            "args": [
                "-y",
                "jev-use"
            ]
        }
    }
}
```

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "jev-use": {
            "type": "stdio",
            "command": "npx",
            "args": [
                "-y",
                "jev-use"
            ]
        }
    }
}
```

### Gemini CLI

**Platform CLI**
```bash
gemini mcp add jev-use npx -y jev-use
```

## When to use it
- pick the next build step without calling the model
- deny a dangerous shell command before it runs
- compact a long transcript down to the messages worth keeping
- rate merge risk before shipping a branch
- keep routine forks out of the agent context

## Example prompts
- Ask Jev whether this branch is safe to merge after a green test run
- Rate the risk of this change from routine to incident
- Gate the command `rm -rf build` and tell me if it should run

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md