README.md
Tamper-proof audit trail for AI decisions.
@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
Install via Smithery (Recommended)
smithery mcp add cronozen/proof
Or connect directly: https://proof.cronozen.com
Self-hosted
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_TOKENenvironment 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
Tools (6)
proof_recordRecords an AI execution as a DPU with a SHA-256 hash chain.proof_verifyVerifies a specific proof record's cryptographic integrity.proof_chain_verifyVerifies the entire SHA-256 hash chain for a domain.proof_getRetrieves a DPU by ID with full details.proof_export_jsonldExports a DPU as a JSON-LD v2.0 document.proof_public_verifyPublicly verifies a DPU's cryptographic integrity without authentication.Environment Variables
CRONOZEN_API_URLBase URL of the Cronozen APICRONOZEN_API_TOKENrequiredJWT Bearer token for API authenticationMCP_PORTPort the MCP server listens onConfiguration
claude_desktop_config.json
{"mcpServers": {"cronozen-proof": {"url": "https://mcp.cronozen.com/mcp", "headers": {"Authorization": "Bearer YOUR_JWT_TOKEN"}}}}Try it
→Record this AI decision as a new proof with domain 'finance' and purpose 'loan approval'.
→Verify the cryptographic integrity of proof record with ID 'dpu-12345'.
→Check the entire SHA-256 hash chain for the 'compliance' domain to ensure no tampering occurred.
→Export the proof record 'dpu-67890' as a JSON-LD document for my audit report.