BLACKVEIL DNS

Know where you stand.

Open-source DNS & email security scanner for Claude, Cursor, VS Code, and MCP clients across Streamable HTTP, stdio, and legacy HTTP+SSE.

Try it in 30 seconds

Claude Desktop (one-click install):

Download the Blackveil DNS extension and open it — all 44 tools available instantly. Verify your download.

Claude Code (one command):

claude mcp add --transport http blackveil-dns https://dns-mcp.blackveilsecurity.com/mcp

Then ask: scan anthropic.com

Smithery (one command):

smithery mcp add MadaBurns/bv-mcp

Verify the endpoint is live:

curl https://dns-mcp.blackveilsecurity.com/health

No install. No API key. One URL for hosted HTTP:

Endpoint   https://dns-mcp.blackveilsecurity.com/mcp
Transport  Streamable HTTP · JSON-RPC 2.0
Auth       None required

Transport support:

• Streamable HTTP: POST /mcp, GET /mcp, DELETE /mcp
• Native stdio: blackveil-dns-mcp CLI from the blackveil-dns npm package
• Legacy HTTP+SSE: GET /mcp/sse bootstrap stream plus POST /mcp/messages?sessionId=...

What you get

• 80+ checks across 20 categories — SPF, DMARC, DKIM, DNSSEC, SSL/TLS, MTA-STS, NS, CAA, MX, BIMI, TLS-RPT, subdomain takeover, lookalike domains, HTTP security headers, DANE, shadow domains, TXT hygiene, MX reputation, SRV, zone hygiene
• Maturity staging — Stage 0-4 classification (Unprotected to Hardened) with score-based capping to prevent inflated labels
• Trust surface analysis — detects shared SaaS platforms (Google, M365, SendGrid) and cross-references DMARC enforcement to determine real exposure
• Guided remediation — generate_fix_plan produces provider-aware prioritized actions; record generators output ready-to-publish records; validate_fix confirms whether a fix was applied successfully
• Supply chain mapping — map_supply_chain correlates DNS signals to build a full third-party dependency graph with trust levels and risk signals
• Attack path simulation — simulate_attack_paths enumerates specific paths (spoofing, takeover, hijack) with severity, steps, and mitigations
• Compliance mapping — map_compliance maps scan findings to NIST 800-177, PCI DSS 4.0, SOC 2, and CIS Controls
• Self-tuning scoring — adaptive weights adjust category importance based on patterns seen across scans via Durable Object telemetry
• Per-tier analytics — usage tracking by auth tier with operator API for tier summaries, key-level usage, and daily digests
• Passive and read-only — all checks use public Cloudflare DNS-over-HTTPS; no authorization required from the target

Tools

  44 MCP tools · 7 prompts · 6 resources

  Email Auth           Infrastructure        Brand & Threats       Meta
 ────────────         ────────────────       ─────────────────    ──────────────────────
  check_spf            check_dnssec           check_bimi           scan_domain
  check_dmarc          check_ns               check_tlsrpt         batch_scan
  check_dkim           check_caa              check_lookalikes     compare_domains
  check_mta_sts        check_ssl              check_shadow_domains compare_baseline
  check_mx             check_http_security                         explain_finding
  check_mx_reputation  check_dane             Intelligence
  check_subdomailing   check_dane_https      ──────────────       Remediation
                       check_svcb_https       get_benchmark       ──────────────
  DNS Hygiene          check_srv              get_provider_        generate_fix_plan
 ────────────          check_zone_hygiene       insights           generate_spf_record
  check_txt_hygiene    check_resolver_        assess_spoofability  generate_dmarc_record
                         consistency          map_supply_chain     generate_dkim_config
                                              resolve_spf_chain    generate_mta_sts_policy
                                              discover_subdomains  generate_rollout_plan
                                              map_compliance       validate_fix
                                              simulate_attack_paths
                                              analyze_drift

  + check_subdomain_takeover (internal — runs inside scan_domain)

Quality & Reliability

The server is continuously validated using a comprehensive chaos test suite (ported from claude-code-py) that covers all 9 detected MCP client types:

• Interactive clients: claude_code, cursor, vscode, claude_desktop, windsurf (auto-format: compact)
• Non-interactive clients: mcp_remote, blackveil_dns_action, bv_claude_dns_proxy, unknown (auto-format: full)

The test suite ensures session stability, authentication precedence, and transport-specific edge cases across Streamable HTTP and Legacy SSE.

Run the chaos tests locally: python3 scripts/chaos/chaos-test-clients.py

Architecture

  MCP Client
      │
      │  POST /mcp (JSON-RPC 2.0)
      │
  ┌───▼──────────────────────┐
  │  Cloudflare Worker       │
  │                          │
  │  Hono ─► Origin check    │
  │       ─► Auth            │
  │       ─► Rate limiting   │
  │       ─► Session mgmt    │
  └───┬──────────────────────┘
      │
  ┌───▼──────────────────────┐
  │  Tool Handlers           │
  │  16 checks in parallel   │
  └───┬──────────────────────┘
      │
  ┌───▼──────────────────────┐
  │  Generic Scoring Engine  │
  │  Three-tier model        │
  └───┬──────────────────────┘
      │
  ┌───▼──────────────────────┐
  │  Cloudflare DoH          │
  │  DNS-over-HTTPS          │
  └──────────────────────────┘

• Generic Scoring Engine: Architectural core ported from claude-code-py for cross-language consistency
• WASM Policy Engine: High-performance permission and token checks via bv-wasm-core
• Reliable Sessions: Hardened tombstone logic prevents race-condition revival of terminated sessions
• Adaptive Scoring: Durable Object telemetry adjusts weights based on real-world distributions
• Client Awareness: Automatic response formatting (compact vs full) based on client User-Agent

Client setup

The free tier requires no authentication. If you have an API key, you can use either:

• Header: Authorization: Bearer <KEY>
• Query Param: ?api_key=<KEY>

For full hosted setup examples, stdio usage, and legacy fallback endpoints, see docs/client-setup.md.

Pricing

| | Free | Pro | Enterprise | |---|---|---|---| | Price | $0 | $39/mo | Contact us | | Scans/day | 75 | 500 | 10,000+ | | Checks/day | 200 | 5,000 | Unlimited | | Rate limit | 50 req/min | None | None | | API access | Yes | Yes | Yes | | MCP access | Yes | Yes | Yes |

Responsible use

This tool is intended for authorized security assessments of domains you own or have explicit permission to test. Do not use it for unauthorized reconnaissance, harassment, or any activity that violates applicable laws. Findings from attack simulation, spoofability, and subdomain discovery tools should be used to improve your own security posture, not to exploit others.

If you discover a vulnerability in a third-party domain, please follow coordinated disclosure practices.

Built and maintained by BLACKVEIL — NZ-owned cybersecurity consultancy.

BUSL-1.1 License (converts to MIT on 2030-03-17)