Nobulex MCP server: compliance and audit for MCP agents

The Model Context Protocol lets agents call tools, but MCP itself has no notion of what an agent is allowed to do, or of a record you can trust afterward. The Nobulex MCP server adds both: covenant rule-checking and signed, hash-chained audit records, to any MCP-compatible client — Claude Desktop, Cursor, and others.

What it is

@nobulex/mcp-server is a Model Context Protocol server (stdio transport, JSON-RPC 2.0) that exposes Nobulex's covenant and verification tools to any MCP client. You point your client at it in config, and the agent gains tools to declare rules, check actions against them, and produce verifiable records — without changing the rest of your setup.

Install and connect

npm install -g @nobulex/mcp-server

Add it to your MCP client config (Claude Desktop, Cursor, and similar):

{
  "mcpServers": {
    "nobulex": {
      "command": "npx",
      "args": ["nobulex-mcp"]
    }
  }
}

The server speaks newline-delimited JSON-RPC 2.0 over stdio, so any MCP-compatible client can drive it.

The tools it exposes

• create_covenant — declare the rules an agent must follow (permitted and forbidden actions, scope limits).
• parse_ccl — parse a covenant written in CCL, the covenant constraint language.
• evaluate_action — check a proposed action against a covenant before it runs, so out-of-scope calls are caught up front.
• verify_covenant — verify a covenant document's signature and constraints, offline.
• create_identity — mint a signing identity for an agent.
• list_covenants — enumerate the covenants in the current store.

Why put this in front of MCP tool calls

MCP standardized how agents reach tools, which is exactly why the accountability gap matters more: an agent that can call anything should leave behind a record that a third party can trust. Every covenant check and verification the server performs rests on the same primitives as the rest of Nobulex — Ed25519 signatures, JCS (RFC 8785) canonicalization, and hash-chaining — so the resulting records are tamper-evident and verifiable offline, with no trust in the operator.

That is the same bilateral receipt pattern that is normative guidance in the OWASP Agentic Skills Top 10 (AST09), and the records map onto EU AI Act Article 12 record-keeping. The MCP server is just the most convenient way to get it in front of a tool-calling agent.

Getting started

npm install -g @nobulex/mcp-server
npx nobulex-mcp

Nobulex is open source (MIT). For the underlying SDK, pip install nobulex or npm install @nobulex/core. For a step-by-step audit-trail build, see the verifiable audit trail guide; for common questions, the FAQ.

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