NOMOS MCP Server

Give your AI agent a governance layer. The NOMOS MCP server lets Claude and any MCP-compatible agent verify decisions against sealed governance artifacts in real time.

What it does

Four tools, one minute to set up:

| Tool | What it does | |---|---| | verify_decision | Check if an AI action is allowed/denied/escalated by your governance rules | | generate_governance | Convert policy documents → sealed .nomos artifact with one call | | detect_contradictions | Analyze policy vs behavior gaps without creating an artifact | | ask_authority | Query a published authority on the NOMOS Exchange marketplace |

Quick start (Claude Desktop)

Add to ~/.claude/claude_desktop_config.json:

{
  "mcpServers": {
    "nomos": {
      "command": "npx",
      "args": ["-y", "nomos-mcp@latest"],
      "env": {
        "NOMOS_API_KEY": "nmk_live_your_key_here"
      }
    }
  }
}

Restart Claude Desktop. Ask Claude: "Verify whether approving a $50,000 loan for a borrower with credit score 680 is allowed by pub_lending_v1."

No API key needed for public artifacts (pub_lending_v1, pub_refund_v1, pub_fraud_v1, pub_hr_leave_v1, pub_kyc_v1).

Tools

verify_decision

Check if a decision is allowed by a governance artifact.

artifact_id  — Artifact ID (pub_lending_v1 for demo, or your own from Studio)
decision     — Action being checked (e.g. "approve_loan", "process_refund")
inputs       — Key/value inputs (e.g. {"amount": 50000, "credit_score": 680})
domain_id    — Your domain ID (required for custom artifacts)
api_key      — Override for NOMOS_API_KEY env var

Response: verdict (allow/deny/escalate), confidence, fired_rule, audit_hash, latency_ms

generate_governance

Convert policy documents to a sealed governance artifact.

name          — Artifact name (e.g. "Loan Approval Policy")
organization  — Your org name
documents     — Array of {filename, content, source_type}
behavioral_logs — Optional historical decision records for triangulation
domain        — Industry hint (lending, hr, e-commerce, healthcare…)
api_key       — Your NOMOS API key

Response: artifact_id, ari_score, rules_extracted, contradictions, seal_hash

detect_contradictions

Analyze policies for hidden conflicts and policy-vs-behavior gaps. Stateless — no artifact created.

documents       — Array of {filename, content}
behavioral_logs — Optional decision history to compare
api_key         — Your NOMOS API key (optional)

ask_authority

Query a published authority on the Exchange — a different system from verify_decision's own governance artifacts. Every public authority is queryable with no key.

authority         — Exchange artifact ID or slug, e.g. "eu-ai-act.nomos"
inputs             — Key/value facts to evaluate (e.g. {"ai_categorises_biometric_data_for_sensitive_attributes": true})
action             — Optional label for your own transcript record
exchange_api_key   — Exchange API key (nxk_...). Optional for free queries; falls back to NOMOS_EXCHANGE_API_KEY env var

Response: verdict (AUTHORIZED/DENIED/ESCALATED), verdict_description, matched_rule_id, missing_inputs, query_id, url (permanent transcript)

Browse the catalog at nomosprotocol.com/exchange.

Getting an API key

1. Go to nomosprotocol.com
2. Sign up free
3. Settings → API Keys → Generate

Links

• Studio — Build and seal governance artifacts
• Artifact Library — Browse pre-built public artifacts
• Docs — Full API reference
• GitHub — Source code