Jev in Cursor
Cursor speaks MCP, so Jev drops in as a decision tool. Add the open jev-mcp server and Cursor's agent can call classify / score / check / gate / decide mid-task — typed, calibrated answers in milliseconds, not a slow, unparseable second model call.
Every example needs a jv_live_ key. Grab one on the pricing page, export it as JEV_API_KEY, and you're ready. Get a key →
Cursor's agent makes a lot of small structured decisions while it works — which file, is this edit safe, does this test failure matter, which approach wins. Done in free-text reasoning those are slow and inconsistent. Jev gives Cursor a typed decision tool it can call and branch on directly, so the agent reserves its model budget for actual coding.
Add Jev to Cursor
Cursor reads MCP servers from .cursor/mcp.json in your project (or ~/.cursor/mcp.json globally). Add jev-mcp — it runs straight from GitHub with npx, no clone or build:
{
"mcpServers": {
"jev": {
"command": "npx",
"args": ["-y", "github:codaaiteam/jev-mcp"],
"env": { "TYPESAFE_API_KEY": "jv_live_..." }
}
}
}Reload Cursor and enable the server in Settings → MCP. The Jev tools appear in the agent's toolset. A hosted jv_live_ key routes to the gateway automatically — no endpoint to configure.
What the agent can now call
- jev_classify — put an input into one of your categories
- jev_score — rate on an ordered scale you define
- jev_check — a calibrated yes/no (noul) with a probability
- jev_gate — allow / confirm / block a risky action before it runs
- jev_decide — many typed questions in one round trip
Because each answer is typed and calibrated, Cursor branches on a probability instead of re-reading its own prose — faster loops, fewer format mistakes, and a real threshold you can set for when to auto-proceed vs. ask you.
Config reference
The key and endpoint details — including the hosted-key gotcha — are on the Jev MCP page, since Cursor uses the same jev-mcp server as every other MCP client.
FAQ
How do I add Jev to Cursor?
Add jev-mcp to .cursor/mcp.json (project) or ~/.cursor/mcp.json (global) as an npx command with your TYPESAFE_API_KEY, then enable it in Settings → MCP. The Jev classify/score/check/gate/decide tools appear in the agent's toolset.
Do I need to host anything for Cursor?
No. jev-mcp runs locally via npx and calls the hosted Jev gateway; the model stays on TypeSafe's infrastructure. You only need a jv_live_ key.
Why use Jev in Cursor instead of another model call?
Speed, cost and reliability. Jev answers in 70–500ms at about $0.001 per decision with output free, and returns a typed value that can't be malformed — versus a slow, pricier LLM call that returns prose you must re-parse.
See also: Jev MCP server (config) · Claude Code integration · Agent skill (all clients)
Try Jev before you wire it in
Run a real, typed decision in the browser — free, no signup — then drop your key into the example above.