Security

Nomik's security model — local-first architecture, threat model, parameterized queries, network isolation, role-scoped access, and built-in security scanning.

Threat Model

Nomik operates as a local sidecar — it never touches production systems. The graph stores metadata about your codebase, not source code.

Threat	Risk	Mitigation
Graph DB exposed to network	HIGH	Bind to `127.0.0.1` only, Docker isolation
Credentials in config files	HIGH	Environment variables, `.env` in `.gitignore`
Cypher injection via MCP	MEDIUM	Parameterized queries only (no string concatenation)
Source code in graph	NONE	Graph stores metadata only — names, paths, line numbers, relationships
Viz dashboard access	LOW	Localhost-only by default
Dependency supply chain	MEDIUM	`nomik audit` with blast radius, lockfile pinning

The graph stores metadata — function names, file paths, line numbers, and relationships. A stolen graph database reveals architecture topology, not implementation details. This makes Nomik compliance-friendly — no PII or secrets are stored in the graph.

2. Parameterized Cypher Only

All graph queries use parameterized values. No string concatenation in Cypher, eliminating injection risk.

Correct — parameterized

session.run('MATCH (n:Function {name: $name}) RETURN n', { name });

Never — injection risk

session.run(`MATCH (n:Function {name: '${name}'}) RETURN n`);

3. Network Isolation

Neo4j is bound to localhost only — no external network access by default.

docker-compose.yml

services:
  neo4j:
    ports:
      - "127.0.0.1:7474:7474"    # Localhost only
      - "127.0.0.1:7687:7687"    # No external access

On Docker Desktop (Windows/macOS), networks: internal: true can block host-to-container port forwarding. The 127.0.0.1 binding is sufficient to prevent external access.

4. Environment-Based Secrets

Credentials are stored in environment variables, never hardcoded.

.env (never committed)

NOMIK_GRAPH_URI=bolt://localhost:7687
NOMIK_GRAPH_USER=neo4j
NOMIK_GRAPH_PASS=nomik_local

5. Role-Scoped MCP Access

The NOMIK_ROLE environment variable restricts which MCP tools the AI assistant can use:

Role	Access Level	Use Case
`dev` (default)	All 21 tools	Full development access
`architect`	Architecture tools only	Architecture review
`security`	Security/audit tools only	Security auditing
`pm`	Stats/reporting tools only	Project management

6. Built-in Security Scanning

Nomik includes multiple security tools that work together:

Dependency audit with blast radius

$ nomik audit

Dependency Audit:

⚠ lodash@4.17.20 — Prototype Pollution (HIGH)
  Blast radius: 12 files import lodash
    src/utils/helpers.ts        (_.merge, _.get, _.set)
    src/services/transform.ts   (_.mapValues)
    ... 10 more files

⚠ axios@0.21.0 — SSRF Vulnerability (MEDIUM)
  Blast radius: 3 files import axios
    src/services/payment.ts
    src/services/email.ts
    src/services/search.ts

2 vulnerabilities found (1 high, 1 medium)

Quality gate with secret detection

$ nomik guard --ci

Quality Gate Check:
  Dead code:       0 (threshold: 5)   ✓
  God files:       2 (threshold: 3)   ✓
  Duplicates:      1 (threshold: 2)   ✓
  Security issues: 0 (threshold: 0)   ✓

PASSED

Architecture rules

$ nomik rules

✓ max-security-issues  0 / 0   PASS

Secret detection patterns: AWS keys (AKIA...), GitHub tokens (ghp_), Stripe keys (sk_live_), Slack tokens (xoxb-/xoxp-), SendGrid, Twilio, JWT secrets, private keys (-----BEGIN RSA PRIVATE KEY-----), basic auth URLs (https://user:pass@host).

False positive reduction: Automatically skips comments, test files, mock data, and placeholder values (xxx, example, test, TODO).

7. CI Integration

.github/workflows/security.yml

name: Nomik Security
on: [push, pull_request]
jobs:
  security:
    runs-on: ubuntu-latest
    services:
      neo4j:
        image: neo4j:5-community
        env:
          NEO4J_AUTH: neo4j/nomik_local
        ports:
          - 7687:7687
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 22
      - run: npm install -g @nomik-ai/cli
      - run: nomik scan .
      - run: nomik audit --ci
      - run: nomik rules --ci
      - run: nomik guard --ci

Or use the all-in-one nomik ci command:

Simplified CI

    steps:
      - uses: actions/checkout@v4
      - run: npm install -g @nomik-ai/cli
      - run: nomik ci    # scan → rules → guard → audit

Both nomik audit --ci and nomik guard --ci exit with code 1 on failure, making them suitable for CI pipelines.