Investigate subdomains, SSL certificates, domain registration details, and DNS records with a Python helper. Run checks across multiple domains, estimate registration availability, and receive structured JSON results without additional packages or API keys.
Passive recon of subdomains, SSL certs, WHOIS, and DNS.
Review the instructions the agent will receive before you install.
Passive domain reconnaissance using only Python stdlib. Zero dependencies. Zero API keys. Works on Linux, macOS, and Windows.
This skill includes scripts/domain_intel.py — a complete CLI tool for all domain intelligence operations.
# Subdomain discovery via Certificate Transparency logs
python SKILL_DIR/scripts/domain_intel.py subdomains example.com
# SSL certificate inspection (expiry, cipher, SANs, issuer)
python SKILL_DIR/scripts/domain_intel.py ssl example.com
# WHOIS lookup (registrar, dates, name servers — 100+ TLDs)
python SKILL_DIR/scripts/domain_intel.py whois example.com
# DNS records (A, AAAA, MX, NS, TXT, CNAME)
python SKILL_DIR/scripts/domain_intel.py dns example.com
# Domain availability check (passive: DNS + WHOIS + SSL signals)
python SKILL_DIR/scripts/domain_intel.py available coolstartup.io
# Bulk analysis — multiple domains, multiple checks in parallel
python SKILL_DIR/scripts/domain_intel.py bulk example.com github.com google.com
python SKILL_DIR/scripts/domain_intel.py bulk example.com github.com --checks ssl,dns
SKILL_DIR is the directory containing this SKILL.md file. All output is structured JSON.
| Command | What it does | Data source |
|---|---|---|
subdomains | Find subdomains from certificate logs | crt.sh (HTTPS) |
ssl | Inspect TLS certificate details | Direct TCP:443 to target |
whois | Registration info, registrar, dates | WHOIS servers (TCP:43) |
dns | A, AAAA, MX, NS, TXT, CNAME records | System DNS + Google DoH |
available | Check if domain is registered | DNS + WHOIS + SSL signals |
bulk | Run multiple checks on multiple domains | All of the above |
web_search for general research about what a domain/company doesweb_extract to get the actual content of a webpageterminal with curl -I for a simple "is this URL reachable" check| Task | Better tool | Why |
|---|---|---|
| "What does example.com do?" | web_extract | Gets page content, not DNS/WHOIS data |
| "Find info about a company" | web_search | General research, not domain-specific |
| "Is this website safe?" | web_search | Reputation checks need web context |
| "Check if a URL is reachable" | terminal with curl -I | Simple HTTP check |
| "Find subdomains of X" | This skill | Only passive source for this |
| "When does the SSL cert expire?" | This skill | Built-in tools can't inspect TLS |
| "Who registered this domain?" | This skill | WHOIS data not in web search |
| "Is coolstartup.io available?" | This skill | Passive availability via DNS+WHOIS+SSL |
Pure Python stdlib (socket, ssl, urllib, json, concurrent.futures).
Works identically on Linux, macOS, and Windows with no dependencies.
All queries are passive — no port scanning, no vulnerability testing:
Contributed by @FurkanL0
No reviews yet. Tell others what you thought.
No login needed. Share how it worked for you, ask a question, or note where it did not run.
No comments yet. Be the first to write one.
Set up the 1Password CLI and use stored passwords or API keys in commands and configuration templates. Choose an authentication method, retrieve secret references, and pass credentials to processes through environment variables.
Build an Excel workbook linking the income statement, balance sheet, and cash flow statement. Populate historical figures, create formula-based forecasts, compare scenarios, and check that balances and cash totals agree across all three statements.
Adapt existing PyTorch training scripts to use multiple GPUs or machines with limited code changes. The skill guides configuration, launch commands, mixed precision, which uses lower-precision numbers, and DeepSpeed or FSDP settings for distributing training work and memory.
Configure Hermes to run AI models through Actual Computer on your own hardware. Set up either the hosted relay or a local connection, select models, verify responses, and troubleshoot request errors or empty output.
Test an app from the perspective of a frustrated, less technical user. Find confusing steps and barriers, separate actionable usability problems from personal complaints, and produce screenshots, suggested fixes, and prioritized tickets.
Resolve Git merge conflicts between two agents by comparing both changes and their stated goals. Combine compatible work, explain choices where designs differ, and verify the merged result with project builds or tests.