FaultKey · CausalLayer MCP Server

Deterministic fault math for multi-party AI incidents. When an AI causes harm and three parties argue over who pays, FaultKey returns a signed, Bitcoin-anchored certificate of fault allocation in under 200 ms — no LLM, no probabilistic scoring, no vendor cooperation needed for a third party to verify.

This is the official Model Context Protocol (MCP) server for the CausalLayer engine, packaged as a Cloudflare Worker. It lets AI agents (Claude Desktop, Cursor, Cline, Continue, Windsurf) call the four core liability-attribution tools without writing a single line of integration code.

Live demo

The public Worker is deployed on Cloudflare's global edge network and is fully functional in standalone demo mode (deterministic responses, watermarked, rate-limited 5 calls / IP / day):

• Endpoint: https://mcp.faultkey.com/mcp (live, custom domain)
• Mirror: https://causallayer-mcp-demo.zykm9qkk7j.workers.dev/mcp
• Healthcheck: /healthz
• Demand telemetry: /stats (public, aggregated, no PII)

Quick start

Claude Desktop

Add this to ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "faultkey": {
      "command": "npx",
      "args": ["-y", "causallayer-mcp"]
    }
  }
}

Restart Claude. Type "List the FaultKey tools."

Cursor

Settings → MCP Servers → Add new:

• Name: faultkey
• Command: npx -y causallayer-mcp

Cline / Continue / Windsurf

{
  "name": "faultkey",
  "command": "npx",
  "args": ["-y", "causallayer-mcp"]
}

Direct HTTP (no CLI)

curl -X POST https://causallayer-mcp-demo.zykm9qkk7j.workers.dev/mcp \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -d '{"jsonrpc":"2.0","id":0

... [View full README on GitHub](https://github.com/smq9sn5jck-coder/causallayer-mcp#readme)