spectral

MCP server for website reconnaissance. Gives Claude the ability to fingerprint tech stacks, audit security headers, map endpoints, analyze SSL certificates, enumerate DNS records, and scan ports.

Install

git clone https://github.com/zohaiblazuli/spectral.git
cd spectral
npm install

Setup with Claude Desktop

Add this to your Claude Desktop config (claude_desktop_config.json):

{
  "mcpServers": {
    "spectral": {
      "command": "node",
      "args": ["/absolute/path/to/spectral/bin/spectral.js"]
    }
  }
}

Restart Claude Desktop. You'll see 6 new tools available.

Setup with Claude Code

Add to your project's .mcp.json:

{
  "mcpServers": {
    "spectral": {
      "command": "node",
      "args": ["/absolute/path/to/spectral/bin/spectral.js"]
    }
  }
}

Tools

`analyze_url`

Fingerprints a website's tech stack from response headers and HTML content.

Detects:

Frameworks: React, Next.js, Vue, Nuxt, Angular, Svelte, Remix, Astro, jQuery
CMS: WordPress, Drupal, Shopify, Squarespace, Wix, Ghost, Webflow
CDN: Cloudflare, Fastly, Akamai, CloudFront, Vercel, Netlify
Analytics: Google Analytics, GTM, Segment, Hotjar, Mixpanel, Plausible, PostHog
Servers: nginx, Apache, Express, IIS, LiteSpeed, Caddy, Deno
Security: reCAPTCHA, hCaptcha, Cloudflare Turnstile

> analyze_url({ url: "vercel.com" })

Tech Stack Report: https://vercel.com/
Status: 200

frameworks: React, Next.js
cdn: Vercel
analytics: Google Analytics

Server: not disclosed
X-Powered-By: not disclosed

`check_headers`

Audits security headers and returns a letter grade (A through F).

Checks: Strict-Transport-Security, Content-Security-Policy, X-Content-Type-Options, X-Frame-Options, Referrer-Policy, Permissions-Policy, X-XSS-Protection, Cross-Origin-Opener-Policy, Cross-Origin-Resource-Policy.

> check_headers({ url: "github.com" })

Security Header Audit: https://github.com/
Grade: A

[PASS] Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
[PASS] Content-Security-Policy: Set (428 chars). Directives look reasonable.
[PASS] X-Content-Type-Options: nosniff
[PASS] X-Frame-Options: deny
[PASS] Referrer-Policy: strict-origin-when-cross-origin
[INFO] Permissions-Policy: Not set — all browser features available by default.
[INFO] X-XSS-Protection: Not set — fine if CSP is present.
[INFO] Cross-Origin-Opener-Policy: Not set.
[INFO] Cross-Origin-Resource-Policy: Not set.

`map_endpoints`

Crawls a page and extracts all links, forms, scripts, stylesheets, and API endpoint references.

> map_endpoints({ url: "example.com" })

Endpoint Map: https://example.com/

Internal links: 3
  /about
  /contact
  /docs

External links: 5
  https://cdn.example.com/...
  ...

API endpoints found: 2
  /api/v1/users
  /graphql

Forms: 1
  POST /api/login — 3 fields

Scripts: 4, Stylesheets: 2

`ssl_info`

Analyzes a hostname's TLS certificate — issuer, validity, expiry countdown, protocol, cipher, SAN list, chain.

> ssl_info({ hostname: "github.com" })

SSL/TLS Report: github.com:443

Subject: github.com
Issuer: DigiCert Global G2 TLS RSA SHA256 2020 CA1 (DigiCert Inc)
Valid from: 2024-03-07T00:00:00.000Z
Valid to: 2025-03-07T23:59:59.000Z
Days until expiry: 187
Protocol: TLSv1.3
Cipher: TLS_AES_128_GCM_SHA256
Serial: 0E8BF3770D92D196F0BB61F93C4166BE

SAN entries (2):
  github.com
  www.github.com

Certificate chain (3 certs):
  1. github.com (issued by: DigiCert Global G2 TLS RSA SHA256 2020 CA1)
  2. DigiCert Global G2 TLS RSA SHA256 2020 CA1 (issued by: DigiCert Global Root G2)
  3. DigiCert Global Root G2 (issued by: DigiCert Global Root G2)

`dns_lookup`

Enumerates DNS records for a hostname.

> dns_lookup({ hostname: "example.com" })

DNS Records: example.com

A:
  93.184.216.34
AAAA:
  2606:2800:220:1:248:1893:25c8:1946
MX:
  10 mail.example.com
NS:
  a.iana-servers.net
  b.iana-servers.net
TXT:
  v=spf1 -all
SOA:
  Primary NS: ns.icann.org
  Admin: noc.dns.icann.org
  Serial: 2024022834

`port_scan`

Quick TCP port scan with service identification.

Default ports: 21 (FTP), 22 (SSH), 80 (HTTP), 443 (HTTPS), 3000, 3306 (MySQL), 5432 (PostgreSQL), 6379 (Redis), 8080, 8443, 27017 (MongoDB).

> port_scan({ hostname: "example.com" })

Port Scan: example.com
Scanned 11 ports — 2 open, 9 closed

Open:
  80/tcp   open  HTTP
  443/tcp  open  HTTPS

Closed:
  21/tcp   closed  FTP
  22/tcp   closed  SSH
  ...

Custom ports:

> port_scan({ hostname: "10.0.0.1", ports: [22, 80, 443, 8080, 9090] })

How It Works

spectral is an MCP (Model Context Protocol) server that runs over stdio. When connected to Claude Desktop or Claude Code, it exposes 6 tools that Claude can call to gather information about websites and servers.

Under the hood:

Tech fingerprinting matches 50+ signatures against response headers, HTML meta tags, script sources, and inline patterns
Header auditing checks 9 security headers against best-practice rules and computes a weighted grade
Endpoint mapping uses cheerio to parse HTML and regex to extract API references from inline scripts
SSL analysis uses Node's tls.connect() to grab the peer certificate directly
DNS enumeration uses dns.promises to query all standard record types
Port scanning uses net.Socket with concurrent TCP connects and 2-second timeouts

No external APIs. No browser automation. No heavy dependencies. Just Node built-ins plus cheerio for HTML parsing.

Requirements

Node.js 18+ (for built-in fetch)
Claude Desktop or Claude Code (for MCP integration)

License

MIT