djtellado/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 file_id (box_analyze) — without leaving the conversation.
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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/claude_desktop_config.json:
Restart Claude Desktop. You will see a 🔌 icon in the chat with the 27 Nexus tools available.
Claude Desktop (Windows)
Edit %APPDATA%\Claude\claude_desktop_config.json with the same contents.
Claude Code (CLI)
Cursor
Edit ~/.cursor/mcp.json:
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.
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The 27 tools
| Tool | Capability | Typical cost |
|---|---|---|
| nexus_analyze | Full legal analysis (Node A — ISO 31000) | 1-3 credits |
| nexus_consulta | Open legal question, with or without a document | 1 credit |
| nexus_draft | Legal drafting (appeal, claim, defence, clause…) | 2-4 credits |
| nexus_audit | Cross-audit of a Node A analysis (Node B) | 1-2 credits |
| nexus_consensus | Multi-agent consensus Node A ↔ Node B (analysis + adversarial audit in a loop until consensus; jurisdiction required; long operation ~3-6 min) | 3-7 credits |
| nexus_monte_carlo | Monte Carlo scenario simulation (ISO 31000 §6) | 4 credits |
| nexus_doctrina | Administrative doctrine search, by jurisdiction | 1 credit |
| nexus_opinion | Multi-LLM second opinion on a previous analysis | 2 credits |
| nexus_redteam | Adversarial red team (vulnerabilities as structured JSON) | 5 credits |
| nexus_adversarial | Adversarial argument in prose over a previous analysis | 2-3 credits |
| nexus_cross_border_compare | Multi-jurisdiction comparison (2-15 jurisdictions) | 2-4 credits |
| nexus_jurisprudencia_search | Semantic search over the multi-jurisdiction case-law corpus | requires balance + the case-law add-on for that jurisdiction |
| verify_cita | Deterministic verification of one citation (judgment or provision) against the official corpus | requires balance (+ case-law add-on if the citation is case law) |
| plazos_calcular | Procedural time limits by forum. jurisdiction is required, no default: ES (LEC + LOPJ, CGPJ/regional holidays, August non-working) or GB-EAW (CPR r 2.8, *clear days*, England and Wales bank holidays, no August recess). Scotland and Northern Ireland are rejected: their rules and their holidays are different | requires balance |
| cruce_normativa_jurisprudencia | Citation graph: provisions ↔ judgments | requires balance + case-law add-on |
| box_analyze | Analysis of a Box file by file_id (requires an active Box connection) | 1-2 credits |
| nexus_verificacion | Verification Centre: checks EVERY citation in a document against the official corpus (deterministic, no LLM cost) | requires balance |
| nexus_playbook | Strategic negotiation playbook over a previous analysis | 2-3 credits |