@cronozen/mcp-server

Tamper-proof audit trail for AI decisions. Record, verify, and export cryptographic proof chains via MCP.

Overview

This MCP server exposes 6 tools for AI decision provenance — recording decisions, verifying cryptographic integrity, and exporting audit-ready evidence. AI clients such as Claude Desktop connect over Streamable HTTP transport and interact with decision proofs through a standard MCP interface.

Transport: Streamable HTTP (not SSE, not stdio)
Session model: Stateful per-session transport with UUID session IDs
Auth forwarding: Per-request Bearer token is forwarded to the underlying API

Tools

Tool	Description	Required Params	Optional Params
`proof_record`	Records an AI execution as a DPU. Creates a cryptographically chained proof record with SHA-256 hash chain.	`domain` (string), `purpose` (string), `final_action` (string)	`evidence_level` (DRAFT \| PARTIAL \| AUDIT_READY), `reviewed_by`, `reviewer_role`, `approved` (boolean), `tags` (string[]), `reference_type`, `reference_id`
`proof_verify`	Verifies a specific proof record's cryptographic integrity. Checks hash consistency.	`proofId` (string)	`data` (Record<string, unknown>)
`proof_chain_verify`	Verifies the entire SHA-256 hash chain for a domain. Reports the first broken index if tampering is detected.	`domain` (string)	`fromIndex` (number), `toIndex` (number), `batchSize` (number)
`proof_get`	Retrieves a DPU by ID with full details including hash chain position, evidence level, and compliance info.	`id` (string)	--
`proof_export_jsonld`	Exports a DPU as a JSON-LD v2.0 document conforming to Cronozen Evidence Ontology. Includes 6W extraction and policy snapshot.	`id` (string)	--
`proof_public_verify`	Publicly verifies a DPU's cryptographic integrity without authentication. Checks hash validity and chain link integrity.	`id` (string)	--

Quick Start

Prerequisites

Node.js 18+
A running Cronozen API endpoint

Install

npm install

Configure

cp .env.example .env

Edit .env and set CRONOZEN_API_TOKEN to a valid JWT token.

Development

npm run dev

Production

npm run build
npm start

Docker

docker build -t cronozen-mcp-server .
docker run -p 3100:3100 \
  -e CRONOZEN_API_URL=https://mcp.cronozen.com \
  -e CRONOZEN_API_TOKEN=your-token \
  cronozen-mcp-server

Environment Variables

Variable	Description	Default
`CRONOZEN_API_URL`	Base URL of the Cronozen API	`http://localhost:3000`
`CRONOZEN_API_TOKEN`	JWT Bearer token for API authentication	(none -- required)
`MCP_PORT`	Port the MCP server listens on	`3100`

Claude Desktop Configuration

{
  "mcpServers": {
    "cronozen-proof": {
      "url": "https://mcp.cronozen.com/mcp",
      "headers": {
        "Authorization": "Bearer YOUR_JWT_TOKEN"
      }
    }
  }
}

Health Check

GET /health

{
  "status": "ok",
  "server": "cronozen-decision-proof",
  "version": "0.1.0",
  "tools": 6,
  "transport": "streamable-http",
  "activeSessions": 0
}

Authentication

The server supports two authentication modes:

Per-session Bearer token — Clients send an Authorization: Bearer <token> header on the initial MCP request. The token is forwarded to all subsequent API calls for that session.
Fallback to environment variable — If no Bearer token is provided in the request, the server uses the CRONOZEN_API_TOKEN environment variable.

The proof_public_verify tool calls the public verification endpoint which does not require authentication.

How It Works

Claude Desktop / AI Client
    |  HTTPS + Bearer token
    v
Cronozen MCP Server (Streamable HTTP)
    |  HTTP + Bearer forwarding
    v
Cronozen Decision Proof API
    |  SHA-256 hash chain
    v
Tamper-proof Evidence Store

Every AI decision is:

Recorded with structured metadata (domain, purpose, action, evidence level)
Chained via SHA-256 hash linking to the previous record
Verifiable — any record or entire chain can be cryptographically verified
Exportable as JSON-LD v2.0 for audit compliance

Use Cases

AI Agent Audit Trail — Track every decision an AI agent makes in production
Compliance Documentation — Auto-generate tamper-proof evidence for SOC2, EU AI Act, Korea AI Basic Act
Decision Provenance — Answer "why did the AI do this?" with cryptographic proof
Human-in-the-Loop Evidence — Record human approval/rejection alongside AI decisions

License

Apache-2.0

@cronozen/mcp-server