Nexus Legal MCP server

@nexus-legal/mcp

MCP (Model Context Protocol) server for Nexus Legal — exposes 27 specialised legal capabilities to Claude Desktop, Claude Code, Cursor and any other MCP-compatible client.

What is this? Connect your Claude to Nexus in 30 seconds. From then on Claude can run ISO 31000 legal analysis, Monte Carlo litigation simulation, case-law search, legal drafting, administrative doctrine, adversarial red teaming, multi-jurisdiction comparison (cross-border), citation verification, procedural time-limit computation, the statute↔case-law citation graph, and analysis of Box files by fileid (boxanalyze) — without leaving the conversation.

Quick install

1. Generate an MCP key

Go to legal.nexusquantum.legal/developers, choose "MCP server", give it a name (e.g. "personal MacBook") and press + Create MCP key. Copy the nlk_... key — it is shown only once.

2. Configure your client

Claude Desktop (macOS)

Edit ~/Library/Application Support/Claude/claudedesktopconfig.json:

{
  "mcpServers": {
    "nexus-legal": {
      "command": "npx",
      "args": ["-y", "@nexus-legal/mcp"],
      "env": {
        "NEXUS_API_KEY": "nlk_YOUR_KEY_HERE"
      }
    }
  }
}

Restart Claude Desktop. You will see a 🔌 icon in the chat with the 27 Nexus tools available.

Claude Desktop (Windows)

Edit %APPDATA%\Claude\claudedesktopconfig.json with the same contents.

Claude Code (CLI)

claude mcp add nexus-legal -- npx -y @nexus-legal/mcp
# Then set your key:
export NEXUS_API_KEY=nlk_YOUR_KEY_HERE

Cursor

Edit ~/.cursor/mcp.json:

{
  "mcpServers": {
    "nexus-legal": {
      "command": "npx",
      "args": ["-y", "@nexus-legal/mcp"],
      "env": { "NEXUS_API_KEY": "nlk_YOUR_KEY_HERE" }
    }
  }
}

3. Try it

In Claude Desktop, type:

Analyse this contract with Nexus in jurisdiction GB, commercial branch, conservative profile: «[paste the contract text here]»

Claude will call the nexus_analyze tool and return the report with certainty locks [L1]/[L2-J]/[L3-NV]/[L4], blocking signals [L5-C]/[L5-P], and a NEXUS-AUDIT-TRAIL block.

The 27 tools

Shortened. The full README is on GitHub.