BLACKVEIL DNS

Know where you stand.

Source-available 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 — the current 80-tool surface is 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=...

For Streamable HTTP, clients should retain the Mcp-Session-Id returned by initialize and send it on every subsequent request, including notifications. Send the negotiated version in MCP-Protocol-Version; unsupported values are rejected with HTTP 400, while expired or terminated sessions return 404 and require a fresh initialize.

Related MCP server: HeaderHawk

What you get

• 80 MCP tools with 19 scoring categories — SPF, DMARC, DKIM, DNSSEC, SSL/TLS, MTA-STS, NS, CAA, MX, BIMI, TLS-RPT, subdomain takeover, HTTP security headers, DANE, SVCB/HTTPS, DANE-HTTPS, subdomailing, reverse DNS (PTR/FCrDNS), and DNSKEY strength

• 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 (artifact=fix_plan) produces provider-aware prioritized actions; its record artifacts (spf_record, dmarc_record, dkim_config, mta_sts_policy, rollout_plan) 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

  80 MCP tools · 7 prompts · 6 resources

  Email Auth             Infrastructure          Brand & Threats       Meta
 ─────────────          ──────────────          ───────────────       ───────────────
  check_mx              check_dnssec            check_bimi            scan_domain
  check_spf             check_ssl               check_tlsrpt          batch_scan
  check_dmarc           check_ns                check_lookalikes      compare_domains
  check_dkim            check_caa               check_shadow_domains  compare_baseline
  check_mta_sts         check_http_security                           explain_finding
  check_subdomailing    check_dane
  check_mx_reputation   check_dane_https        DNS Hygiene           Remediation
                        check_svcb_https       ─────────────         ───────────────
                        check_ptr               check_txt_hygiene     generate (one tool;
  Intelligence          check_srv                                       artifact=fix_plan,
 ─────────────          check_zone_hygiene                              spf_record,
  get_benchmark         check_resolver_         Discovery               dmarc_record,
  get_domain_rank         consistency          ─────────────           dkim_config,
  get_provider_                                 discover_brand_         mta_sts_policy,
    insights            check_dbl                domains                rollout_plan)
  assess_spoofability   check_rbl               brand_audit_single    validate_fix
  map_supply_chain      cymru_asn               brand_audit_batch_
  analyze_drift         rdap_lookup               start
  resolve_spf_chain     check_nsec_             brand_audit_status
  discover_subdomains     walkability           brand_audit_get_
  map_compliance        check_dnssec_chain        report
  map_csc_products
  prioritize_csc_leads
  simulate_attack_paths check_fast_flux         list_brand_audit_watches
  check_agent_discovery check_dnskey_strength
                        check_authoritative_dns_infra
                        check_root_server_set   register_brand_audit_watch
                                                delete_brand_audit_watch

  + check_subdomain_takeover (standalone tool + internal — runs inside scan_domain)
  + check_authoritative_dns_infra and check_root_server_set (authoritative DNS infrastructure profile)
  + discover_brand_domains_start / discover_brand_domains_status / discover_brand_domains_findings
    (async start → poll → fetch sibling of discover_brand_domains, for clients that time out on the ~24s sync call)

  Operator-deploy only (BV_RECON binding; degrade to unprovisioned on self-hosted BUSL deployments):
  + check_realtime_threat_feed   — curated intel-gateway threat feed lookup
  + scan_buckets_start           — async cloud-bucket discovery scan (start → poll → findings)
  + scan_buckets_status          — poll status of a running bucket scan
  + scan_buckets_findings        — retrieve findings for a completed bucket scan
  + osint_investigate_domain_start          — async domain OSINT investigation (start → poll → report)
  + osint_investigate_infrastructure_start  — async deep-infrastructure OSINT (domain, IP, or org)
  + osint_investigate_supply_chain_start    — async supply-chain OSINT investigation
  + osint_investigate_username_start        — async username OSINT (owner/enterprise tier only)
  + osint_investigate_email_start           — async email OSINT (owner/enterprise tier only)
  + osint_investigation_status   — poll status of any running OSINT investigation
  + osint_investigation_report   — retrieve report for a completed OSINT investigation

  Operator-deploy only (proxied via the `BV_WEB` service binding, wired as the `m365Proxy` runtime option; Microsoft 365 / Entra identity security ops — degrade to unprovisioned without it):
  + query_signins                — query Microsoft Entra sign-in logs for a tenant
  + query_ual                    — query the Microsoft 365 Unified Audit Log for a tenant
  + get_ca_policies              — retrieve Conditional Access policies for an Entra tenant
  + assess_coverage              — assess Conditional Access coverage gaps for an Entra tenant

Tool discovery metadata (_meta)

tools/list returns every tool with server-specific discovery metadata under each tool's _meta (the MCP-sanctioned extension point), so a client can group or filter the surface without hard-coding tool names:

• group — functional group (email_auth, infrastructure, brand_threats, dns_hygiene, intelligence, remediation, discovery, identity_secops, meta).

• tier — scoring tier (core / protective / hardening); absent for non-scoring tools.

• scanIncluded — true when the tool runs inside scan_domain's parallel audit.

• recommended — present (true) only on the curated starter set (scan_domain, explain_finding, compare_baseline); omitted otherwise. A client facing the full surface can lead with tools.filter(t => t._meta.recommended) to avoid overwhelming an LLM with all tools flat. Every tool is still listed — this is an additive signal, not a filter.

Authoritative DNS infrastructure

check_authoritative_dns_infra scores authoritative DNS hosting behavior for a hostname. It is designed to consume raw UDP/TCP DNS, authoritative AA/RA behavior, zone-transfer refusal, DNSSEC, abuse-resistance, BGP/RPKI, and multi-vantage evidence from the BV_INFRA_PROBE service binding when that worker is provisioned.

check_root_server_set validates the DNS root-server set against the embedded official root hints. With BV_INFRA_PROBE, it also checks live root priming, glue, parent/child delegation, DNSKEY, and SOA serial evidence across roots.

Self-hosted or local deployments without BV_INFRA_PROBE still return structured partial results. The worker-only mode records the embedded root hints and marks live raw-DNS, routing, RPKI, and vantage capabilities as inconclusive rather than pretending they ran.

Quality & Reliability

The server is continuously validated using a comprehensive chaos test suite that covers all 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 bv_load_test class identifies internal load/chaos/tranco-scan traffic so it stays out of real-client analytics segments.

The test suite ensures session stability, authentication precedence, format negotiation, and transport-specific edge cases across Streamable HTTP and Legacy SSE. Without an API key it exercises the public/free-tier path; with a valid key exported as BV_API_KEY, it covers Bearer authentication, legacy self-host ?api_key= compatibility, authenticated SSE bootstrap, and authenticated batch behavior.

Run the client/session chaos suite locally: python3 scripts/chaos/chaos-test-clients.py.

Run repeat force-refresh scans to detect production scoring drift:

BV_API_KEY=... python3 scripts/chaos/score-stability-test.py --count 20 --rounds 3 --concurrency 5

The stability harness negotiates MCP protocol 2025-06-18, accepts JSON and Streamable HTTP SSE responses, and exits non-zero on any transport/tool error or score/category drift. Use --from <json-file> with a JSON array of domains for a targeted provider-diversity sweep.

SSOT guardrails are enforced by focused audit tests:

• Tool counts and public resource copy are derived from the TOOLS registry.

• Domain-required validation is derived from each tool input schema.

• Scan timeout budgets are resolved from shared runtime config.

• WASM tool permissions are generated from MCP tool annotations.

• Public quota copy is checked against runtime quota config.

Architecture

  MCP Client
      │
      │  POST /mcp (JSON-RPC 2.0)
      │
  ┌───▼──────────────────────┐
  │  Cloudflare Worker       │
  │                          │
  │  Hono ─► Origin check    │
  │       ─► Auth            │
  │       ─► Rate limiting   │
  │       ─► Session mgmt    │
  └───┬──────────────────────┘
      │
  ┌───▼──────────────────────┐
  │  Tool Handlers           │
  │  19 scoring categories   │
  └───┬──────────────────────┘
      │
  ┌───▼──────────────────────┐
  │  Generic Scoring Engine  │
  │  Three-tier model        │
  └───┬──────────────────────┘
      │
  ┌───▼──────────────────────┐
  │  Cloudflare DoH          │
  │  DNS-over-HTTPS          │
  └──────────────────────────┘

• Generic Scoring Engine: Runtime-agnostic, string-keyed three-tier scoring with configurable weights

• Infra Probe Binding: Optional BV_INFRA_PROBE service binding supplies raw authoritative DNS, root-server, BGP/RPKI, and vantage evidence for the authoritative DNS infrastructure profile

• 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

• Protocol Enforcement: Unsupported MCP versions fail closed; notifications and SSE connections use the same session-validity rules as other post-initialize requests

• Bounded Egress: Public CT and target-HTML responses are streamed under byte ceilings before parsing or fingerprinting

• Cryptographic Identifiers: Session and CSC report identifiers use Web Crypto randomness

• 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

Brand-discovery modes (discover_brand_domains / brand_audit_*)

The discovery_mode argument accepts two values:

• classic (the default everywhere this repo runs out-of-the-box) — the public, BUSL-licensed signal-sweep pipeline. Uses only public-internet data sources (DNS, RDAP, CT logs, MX/TXT inspection). This is the only mode supported for self-hosted deployments and the only mode the open test suite covers end-to-end.

• tiered — layers a portfolio-aware Tier 0 / infrastructure-graph Tier 1 / declared-evidence Tier 2 pipeline in front of the classic sweep. Tiered mode requires private BlackVeil-internal cross-Worker bindings (BV_INFRA_GRAPH, BV_INTEL_GATEWAY, BV_ENTERPRISE) that are not packaged with the open distribution — they live in BlackVeil's production deploy overlay (.dev/wrangler.deploy.jsonc) and call into proprietary Workers. Self-hosters cannot enable tiered mode without those bindings.

BlackVeil's hosted production at dns-mcp.blackveilsecurity.com flips its runtime default to tiered via the env var BRAND_AUDIT_DISCOVERY_MODE_DEFAULT="tiered" in the private overlay; the public schema default in src/schemas/tool-args.ts stays 'classic' permanently so anyone building from main gets the BUSL-licensed behaviour unchanged. An explicit caller-supplied discovery_mode always wins over the env default.

Client setup

The free tier requires no authentication. Authenticated requests bypass per-IP rate limits and follow your tier's daily quota. Hosted production supports:

• Header: Authorization: Bearer <KEY>

• OAuth 2.1: optional authorization-code flow with PKCE, enabled only when operators set ENABLE_OAUTH=true; owner-key consent is separately gated by ENABLE_OWNER_OAUTH=true.

The ?api_key=<KEY> fallback is legacy/self-host compatibility only. BlackVeil hosted production sets REJECT_QUERY_API_KEY=true; clients that cannot send headers should use OAuth or an mcp-remote header bridge.

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

Operator configuration

These settings apply to operators running their own deployment. They are optional — self-hosted (BUSL) deployments fall back to privacy-preserving defaults when they are unset.

Detailed analytics capture

The public /mcp path writes a per-event access log enriched with geolocation and network identity. The write path, PII depth, and retention are operator-controlled:

Internal analytics endpoints

These live under the internal auth gate (/internal/*) and are called by bv-web, not the public surface:

Pricing

Offensive/recon and multi-domain tools (subdomain discovery, attack-path simulation, lookalike/shadow-domain detection, fast-flux detection, supply-chain mapping, real-time threat feed, bucket/OSINT investigations, batch_scan, compare_domains, brand audits) require a paid plan (Pro / developer tier or higher); free, unauthenticated, and agent-tier callers get an HTTP 403 upgrade-required response. Unauthenticated callers are additionally capped at a small number of distinct domains per day (best-effort, fail-open). The OSINT/bucket status and report pollers stay free.

Example prompts

These demonstrate core functionality — paste any of them into Claude with the Blackveil DNS connector enabled:

Support

• Bug reports & feature requests: GitHub Issues

• Security vulnerabilities: security@blackveilsecurity.com (see SECURITY.md)

• General questions: GitHub Discussions

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.

Privacy Policy · License (BUSL-1.1 → MIT on 2030-03-17)