SystemOne: Universal Decision Model Runner & MCP Server

Model Context Protocol (MCP) server, CLI runner, and TypeScript SDK for System One Decision Models (Laya, Jev, and OpenAI-compatible engines). Built for Claude Code, Oh My Pi (OMP), Cursor, Windsurf, Cline, and terminal workflows.

Works with any OpenAI-compatible endpoint, direct TypeSafe decision gateway, or local offline CPU inference.

⚡ Quickstart

1. Interactive Setup (Zero Install)

Run the setup wizard to configure your agent automatically:

npx -y -p systemone-judge systemone setup

The wizard auto-detects Claude Code, Oh My Pi, Cursor, or local workspaces and configures the connection.

2. Run MCP Server Directly

# In your .mcp.json or agent config:
npx -y -p systemone-judge systemone-mcp

3. One-Liner System Install (Standalone Binaries)

No Node.js or Bun runtime required.

Linux & macOS:

curl -fsSL https://raw.githubusercontent.com/Ridlo543/systemone-judge/main/install.sh | bash

Windows (PowerShell):

irm https://raw.githubusercontent.com/Ridlo543/systemone-judge/main/install.ps1 | iex

Related MCP server: jev-domain-mcp

🧠 Supported Engines: Jev & Laya

systemone supports two decision engines depending on your latency, privacy, and context length requirements:

Running with Laya (Local CPU)

When running locally with Laya, simply pass --laya or set SYSTEMONE_MODEL=laya:

# Boolean assertion on local CPU (300ms, offline)
s1 "1 + 1 = 2" "Is 1+1 equal to 2?" --laya

# Screen command before executing
s1 "rm -rf /var/log/*" "Is this safe to run automatically?" --laya

Note: If using Laya locally, start the local runner with laya start (or node server.mjs on port 20130).

🔌 Agent Integration (MCP Configuration)

Claude Code (~/.claude.json)

{
  "mcpServers": {
    "systemone": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "-p", "systemone-judge", "systemone-mcp"],
      "env": {
        "SYSTEMONE_BASE_URL": "https://api.openai.com/v1",
        "SYSTEMONE_MODEL": "systemone",
        "SYSTEMONE_API_KEY": "${API_KEY}"
      }
    }
  }
}

Oh My Pi (~/.omp/agent/mcp.json)

{
  "mcpServers": {
    "systemone": {
      "type": "stdio",
      "command": "systemone-mcp",
      "args": [],
      "env": {
        "JEV_BASE_URL": "http://127.0.0.1:20130/v1",
        "JEV_MODEL": "laya",
        "JEV_API_KEY": "none"
      }
    }
  }
}

Cursor & Windsurf (.cursor/mcp.json or .cline/mcp.json)

{
  "mcpServers": {
    "systemone": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "-p", "systemone-judge", "systemone-mcp"],
      "env": {
        "SYSTEMONE_BASE_URL": "https://api.openai.com/v1",
        "SYSTEMONE_MODEL": "systemone",
        "SYSTEMONE_API_KEY": "${API_KEY}"
      }
    }
  }
}

💻 CLI Usage & Deterministic Contracts

systemone (or short alias s1) enforces strict input contracts: files are strictly read from disk, inline strings are never mistaken for files, and - reads from standard input.

1. Code Review (s1 review)

Evaluates patch correctness, specification alignment, test coverage gaps, and blast radius:

# From file:
s1 review -f path/to/changes.patch --request "Fix division by zero in math module"

# Piped from git:
git diff | s1 review - --request "Refactor auth middleware to JWT"

2. Definition-of-Done Acceptance Gating (s1 gate)

Verifies diff quality and audits completion claims against test output to prevent fake completion:

git diff | s1 gate - \
  --request "Add connection pooling" \
  --evidence-file test-results.log \
  --claim "Unit tests pass with 100% coverage" \
  --claim "No secret keys logged"

3. Action Safety Screening

Evaluates command risk with defense-in-depth enforcement:

s1 "rm -rf / --no-preserve-root" "Is this command destructive?" --laya

4. Categorical Classification

s1 -s "PostgreSQL connection pool exhausted" -c "network,database,client"

🛠️ Tool Reference

By default, systemone exposes 8 core orthogonal tools to eliminate cognitive ambiguity in agents (with action_gate and legacy jev_* supported as aliases):

(Set SYSTEMONE_TOOLS="all" in environment to expose the extended 14-tool surface including regex field extractors).

📊 Formatter Output Examples

systemone_review

🔍 Diff Review: 🟢 AUTO (Composite: 0.88 / 1.0)

• Safe to Apply: true

• Decision Recommendation: auto

### `systemone_action_gate`
### 🛡️ Action Safety Gate: 🛑 BLOCK (Risk: 2.85 / 3.0)

- **Action/Command:** `rm -rf / --no-preserve-root`
- **Recommendation:** **BLOCK**
- **Destructive Operation:** `YES`
- **Requires Human Escalation:** `YES`
- **Safety Analysis:** Destructive root recursive deletion detected

⚙️ Configuration Hierarchy

Settings resolve in order of precedence:

1. Explicit CLI flags (--base-url, --api-key, --model, --protocol, --laya)

2. MCP client environment (env block in .mcp.json)

3. Local configuration file (jev.config.json)

4. Local .env file

5. System environment variables

📦 Standalone Binaries

Download precompiled standalone binaries from GitHub Releases:

• Windows x64: systemone-windows-x64.exe & systemone-mcp-windows-x64.exe (aliases: jev-windows-x64.exe)

• Linux x64: systemone-linux-x64 & systemone-mcp-linux-x64 (aliases: jev-linux-x64)

• Linux arm64: systemone-linux-arm64 & systemone-mcp-linux-arm64

• macOS Apple Silicon (arm64): systemone-darwin-arm64 & systemone-mcp-darwin-arm64

🧪 Verification & Testing

Run the automated test suite:

bun test

Covers fail-closed Zod schemas, deterministic argument contracts, defensive truncation, calibration normalizations, and live inference regression suites.

📄 License

MIT License. Copyright (c) 2026 TypeSafe Jev Decision Runner Contributors.