jev-mcp (rashedInt32)
npm MCP server and Claude Code plugin exposing Jev classify, score, check and batched-ask tools with full probability distributions.
Overview
This jev-mcp is an MCP server published on npm that exposes TypeSafe Jev as typed judgment tools: classification, scoring, yes/no checks and batched questions. The README stresses that Jev returns a typed answer and a calibrated distribution, never prose, and that the tools surface the distribution rather than hiding it behind a label.
It ships as a Claude Code plugin that registers the server and an agent skill together, running the published package through npx so nothing needs building. Much of the README documents practical details: the key is read from TYPESAFE_API_KEY, then JEV_API_KEY, then a ~/.config/typesafe/key file, and is never a tool argument; the plugin declares the server inline and deliberately omits an env block to avoid shadowing the key-file fallback. These notes make it useful as a reference for packaging MCP servers as Claude Code plugins.
What the decision model decides
| Type | Question | Answers |
|---|---|---|
| Choice | Classify the state into one of the given labels(inferred) | — |
| Score | Rate the state against an ordered rubric(inferred) | — |
| Yes / no | Check whether a condition holds(inferred) | yes · no |
How it works
- Install via the Claude Code plugin marketplace or npx jev-mcp
- Provide the key through env or ~/.config/typesafe/key
- The agent calls classify, score, check or a batched ask
- The full typed answer and distribution are returned
Strengths
- One-step Claude Code plugin install including the agent skill
- Key never appears in transcripts or tool arguments
- Published package, nothing to build
Caveats
- Requires Node 20.12+ and a TypeSafe key
- Registering both the plugin and the direct server creates duplicate servers
Getting started
/plugin marketplace add rashedInt32/jev-mcp then /plugin install jev@jev-mcp, or claude mcp add --scope user jev -- npx -y jev-mcpAt a glance
- Type
- MCP server
- Status
- beta
- Language
- TypeScript
- Runtime
- Node MCP server / Claude Code plugin
- Has code
- yes
- License
- MIT
Use cases and integrations
How curated lists describe it
An MCP server and Claude Code plugin for Jev classification, scoring, checks and batched questions.
logicrw/awesome-jev-projectsMCP server exposing TypeSafe Jev as typed, calibrated judgment tools: classify, score, check, batched ask. Ships as a Claude Code plugin.
hellogumbo/awesome-jev
Frequently asked questions
What tools does it provide?
Classification, scoring, yes/no checks and batched questions against TypeSafe Jev.
Where does it read the API key?
From TYPESAFE_API_KEY, then JEV_API_KEY, then ~/.config/typesafe/key.
Why does the plugin have no env block?
An empty env value would shadow the key-file fallback and cause missing-key errors.
Related projects
- Building with Jev★ 155
Agent skill for writing and improving programs that call Jev: question design, state structure, thresholds and diagnosing wrong answers.
Agent skillproduction Go MCP server giving any client typed Jev decisions via OpenRouter or TypeSafe, with validated answers and no paid retries.
MCP serverproductionGoUnofficial hosted or local Jev MCP server giving agents a quick second opinion: it picks yes/no, scale or choice and returns probabilities.
MCP serverbetaTypeScriptCLI, MCP server and Claude Code plugin for closed-form yes/no, choice, score and rank decisions via Jev, OpenAI Decisions or Claude.
MCP serverbetaTypeScriptPortable Agent Skill teaching coding agents to use Jev as a bounded judgment layer, plus an optional MCP bridge.
MCP serverbetaTypeScriptIndependent agent skill that makes a coding agent design, build, test and tune a bounded Jev decision layer with a contract first.
Agent skillbeta