What is jevguard-mcp?

An MCP server that exposes JevGuard primitives to AI coding agents: a deterministic guardrail, a local SQLite cache and an execution gate, delivered over JSON-RPC 2.0 on stdio per the MCP 2024-11-05 specification.

Which tools does it expose?

Seven: evaluate_command_safety, verify_code_patch, evaluate_decision, evaluate (full RLCD pipeline), calibrate, prune_state and cache_fingerprint. All use the jevguard_ prefix, and legacy names without it remain supported as aliases.

How do I install and wire it up?

pip install jevguard-mcp, or run python -m jevguard_mcp.server without installing. Point Claude Desktop, Cursor or LibreChat at the command with TYPESAFE_API_KEY in the environment; the README shows JSON config for each client.

What verdicts does command safety return?

ALLOW_AUTONOMOUS for commands it can gate through, REQUIRE_HUMAN_APPROVAL when a person should decide, and DENY_DESTRUCTIVE for destructive operations. Arguments include command, working_dir and elevated_privileges.

Does it need a TypeSafe API key or other dependencies?

The package has zero dependencies — standard library only, Python 3.10+. The client config sets TYPESAFE_API_KEY for the Jev-backed tools; the package itself ships nothing beyond the standard library.

What do calibrate, prune_state and cache_fingerprint do?

calibrate detects tie breaks and low margins from answers and returns AMBIGUOUS_STATE or CONFIDENT; prune_state strips dead keys and breaks cycles; cache_fingerprint masks volatile timestamps and hashes into a canonical SHA-256 string.

Which clients does the README cover?

Claude Desktop on Windows, macOS and Linux, Cursor via Features → MCP Servers or .cursor/mcp.json, and LibreChat via librechat.yaml. Each configuration runs the same stdio command with your TypeSafe key in env.

Jev directory

CommunityJev Agents & MCP

JevGuard MCP Server

Official MCP server for JevGuard and TypeSafe AI: zero-dependency guardrails over JSON-RPC 2.0 on stdio, gating shell commands and code patches, caching decisions in local SQLite and pruning state.

See highlights Open github.com

Stars: 2
Language: Python
License: MIT
Reading time: 2 min
Published by: Community
Author: seb4ez
Last verified: Oct 2026

seb4ez/jevguard-mcp

User repository on GitHub

View on GitHub

Official Model Context Protocol (MCP) server for JevGuard and TypeSafe AI

Forks: 0
Last pushed: Updated Sep 2026

Repo stats from the GitHub API, cached Oct 2026.Homepage

Tagscommunity catalog-import cobanov mcp guardrails claude-desktop

Works forJev for Decision gating Jev for Verification Jev for Tool calling

Used inJev for Software & DevTools Jev for Security & Privacy

Languages: Python
Platforms: MCP SQLite
Capabilities: Open sourceRequires API key

Highlights

Adheres to MCP 2024-11-05 over stdio with zero dependencies — Python standard library only — and supports Python 3.10+.
jevguard_evaluate_command_safety gates shell commands with ALLOW_AUTONOMOUS, REQUIRE_HUMAN_APPROVAL or DENY_DESTRUCTIVE verdicts.
jevguard_verify_code_patch audits diffs for security regressions with APPROVE, REQUEST_CHANGES or REJECT, using a risk_tolerance argument.
Also exposes jevguard_evaluate, calibrate, prune_state and cache_fingerprint, plus a local SQLite cache with a bypass_cache option.
Works with Claude Desktop, Cursor (.cursor/mcp.json) and LibreChat (librechat.yaml); install is pip install jevguard-mcp.

Quickstart

bash

pip install jevguard-mcp
python -m jevguard_mcp.server

Watch out

Copy reviewed against the truncated repo README on 2026-10-15; the excerpt cuts off at the atomic-tools section. The package self-describes as the official MCP server for JevGuard and TypeSafe AI, a claim taken from the README rather than independently verified.

Questions about this entry

Short answers drawn from the linked project or page.

Reactions & coverage

Posts, threads, and videos about this entry from around the web.

X: Jev in front of the HeyGen MCP

X: Playwright CLI + Jev vs Playwright MCP

X: A local MCP server that cuts computer use from 23s to 0.8s. Cartwright built Cortex, a local MCP server where…

X: A side panel that drives any site's WebMCP tools

From the Jev guides

Original write-ups on what this entry is for.

MCP tool routing: Jev in front of the tool call

Oct 16, 2026

Tool menus can outgrow the context that reads them. The catalog's Jev-based routers and gates narrow the list: benchmarked tool search, per-tool scoring, fail-closed approvals, and WebMCP in the browser.

Jev Agents & MCP#mcp#tool-routing#agents

Read article

Approval policies for coding agents: hooks, guards, and gateways

Oct 16, 2026

How the Jev guard family turns coding-agent permissions into auto-approve, deny, or ask: hooks that enforce, guards that fail safe, and gateways that gate generation.

Jev Agents & MCP#coding-agents#guardrails#hooks