jev-mcp-spring
Java/Spring Boot MCP server exposing Jev classify, score, check and patch-gate tools over HTTP instead of stdio.
Overview
Jev MCP Server (Spring) is a Java and Spring Boot MCP server that exposes TypeSafe Jev as typed-judgment tools over HTTP (Streamable or SSE). It targets MCP clients that reach a running service rather than spawning a local subprocess, and the Java side of the ecosystem. It wires the jev-spring-boot-starter client into Spring AI's MCP server support.
Tools are jev_classify (label, confidence, probabilities), jev_score against an ordered rubric, jev_check returning a probability with a flag, uncertain or clear band, jev_gate that verifies completion claims against a diff and evidence and scores merge risk to give pass or review, and jev_health. Failures surface at the MCP protocol level with a short safe message and never echo response bodies or stack traces. A generic ask tool, candidate matching and prompt-injection screening are listed as not implemented yet. The author notes it is an independent community project.
What the decision model decides
| Type | Question | Answers |
|---|---|---|
| Choice | jev_classify: which given label fits the state? | — |
| Yes / no | jev_check: does this yes/no condition hold? | flag · uncertain · clear |
| Choice | jev_gate: should this patch merge given its claims and evidence? | pass · review |
How it works
- Run the Spring Boot service with TYPESAFE_API_KEY
- Point an HTTP-capable MCP client at it
- The agent calls classify, score, check or gate
- Typed results return; failures surface as isError with safe messages
Strengths
- HTTP transport for clients that cannot spawn subprocesses
- Safe error handling that never leaks bodies or stack traces
- Apache-2.0 licence and CI
Caveats
- Implements a subset of tools; ask, match and screen are not yet available
- Requires Java 17+ and your own TypeSafe key
- Independent, unofficial project
Getting started
With Java 17+, export TYPESAFE_API_KEY and start the Spring Boot application as described in the README.At a glance
- Type
- MCP server
- Status
- beta
- Language
- Java
- Runtime
- Spring Boot MCP server (HTTP/SSE)
- Has code
- yes
- Has tests
- yes
- License
- Apache-2.0
Use cases and integrations
How curated lists describe it
On success each tool returns its typed result directly. On failure the tool call fails at the MCP protocol level (\`isError: true\`) with a short, safe message — no response body or stack trace is ever echoed back.
logicrw/awesome-jev-projects
Frequently asked questions
Why HTTP instead of stdio?
It is for MCP clients that connect to a running service rather than spawning a local process.
What does jev_gate decide?
It verifies completion claims against a diff and evidence, scores merge risk and returns pass or review.
Which tools are missing?
A generic ask tool, candidate matching and prompt-injection screening are tracked as follow-ups.
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