mcp-jev

Standalone MCP server for Jev (TypeSafe AI's probabilistic decision model). State in, declared questions out as typed answers + probabilities. Use it from Cursor, Claude Code, or any MCP host.

Also usable as an importable library (@livx.cc/mcp-jev/jev).

Quick Start

# MCP stdio (from npm)
bunx -y @livx.cc/mcp-jev --stdio

# From a clone — loads ./.env (or --env-path /path/to/.env)
bun run dev

# HTTP mode (REST /api/jev/evaluate + MCP /api/mcp); PORT defaults to 3854
bun run http

Environment variables

| Variable | Required | Description | |----------|----------|-------------| | AI_GATEWAY_API_KEY | One of* | Vercel AI Gateway key (vercel provider) | | OPENROUTER_API_KEY | One of* | OpenRouter key (openrouter provider) | | TYPESAFE_API_KEY | One of* | TypeSafe direct key (typesafe provider) | | JEV_PROVIDERS | No | Fallback order (default vercel,openrouter,typesafe) | | JEV_VERCEL_MODEL | No | Default typesafe-ai/jev | | JEV_OPENROUTER_MODEL | No | Default typesafe/jev-1.13 | | JEV_TYPESAFE_MODEL | No | Default jev-latest |

*At least one provider key is required.

MCP Tool

| Tool | Description | |------|-------------| | post_jev_evaluate | { state, questions[], provider? } → { provider, model, answers, usage? } |

| type | criteria | answer | |------|----------|--------| | choice | { option: description } | { choice, probabilities, confidence? } | | score | ["level 0", "level 1", ...] (>=2 string labels) | { score, probabilities, confidence? } | | boolean | optional { true, false } | { probability } |

Answer shape is identical across providers. model is the provider-reported model id.

Providers

Order: provider arg > JEV_PROVIDERS > default. Unconfigured providers are skipped; failures fall through.

• vercel — Vercel AI Gateway evaluation-model API
• openrouter — OpenRouter Decisions API (alpha)
• typesafe — direct API POST https://api.typesafe.ai/v1/systemone (TYPESAFE_API_KEY, model JEV_TYPESAFE_MODEL, default jev-latest)

Adding a vendor = one file in src/providers/ + one entry in PROVIDERS (src/jev.ts).