Jev MCP server

jev-mcp is the open MCP server that exposes Jev's decision primitives — classify, score, check, gate, decide — as tools any MCP client (Claude Code, Cursor, Codex, OpenCode) can call. It runs straight from GitHub with npx and picks the right endpoint from your key.

If you reached this page because a Jev MCP setup returned an authentication error, the fix is almost always the endpoint — see the gotcha below. If you're setting it up fresh, it's two lines.

Install

The fastest path in Claude Code:

claude mcp add jev -e TYPESAFE_API_KEY=your_key -- npx -y github:codaaiteam/jev-mcp

Or add it to any MCP client's config (Cursor, Codex, OpenCode, your own):

{
  "mcpServers": {
    "jev": {
      "command": "npx",
      "args": ["-y", "github:codaaiteam/jev-mcp"],
      "env": { "TYPESAFE_API_KEY": "jv_live_..." }
    }
  }
}

The five tools

• jev_classify — pick one of your labelled options (routing, categorization, intent)
• jev_score — rate the input on an ordered scale you define (risk, urgency, quality)
• jev_check — a calibrated yes/no probability (gates, filters, guardrails)
• jev_gate — risk-screen an action before it runs → allow / confirm / block
• jev_decide — full power: many typed questions in one round trip

Environment variables

Only the key is required — the endpoint is chosen from it automatically:

TYPESAFE_API_KEY   Your Jev key (aliases: JEV_API_KEY, JEV_KEY). Required.
JEV_BASE_URL       auto — chosen from your key:
                     jv_live_… key → https://jevtypesafeai.com/api/v1/decide
                     other key     → https://api.typesafe.ai/v1/systemone
                   Set explicitly to route through your own gateway.
JEV_MODEL          jev-latest  (pin e.g. jev-1.13.0 in production)

Gotcha: a hosted jv_live_ key only works at the gateway

A hosted jv_live_… key is valid ONLY at the jevtypesafeai.com gateway, not at api.typesafe.ai. Current jev-mcp detects a jv_live_ key and routes it there automatically, so you don't touch JEV_BASE_URL. If you're on an older version and a hosted key returns 401 authentication_error, upgrade — or set JEV_BASE_URL=https://jevtypesafeai.com/api/v1/decide explicitly. An official TypeSafe key (from console.typesafe.ai) uses api.typesafe.ai by default.

Route through your own gateway

Set JEV_BASE_URL explicitly to send calls through your own gateway instead — Vercel AI Gateway, OpenRouter, or Cloudflare. Everything else stays the same.

FAQ

See also: Cursor integration · Claude Code integration · jev-mcp & open source