Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add crazyMarky/pentest-skills --skill recon-subdomaingit clone --depth 1 https://github.com/crazyMarky/pentest-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/crazymarky/pentest-skills/recon-subdomain)<a href="https://agentmods.dev/skills/crazymarky/pentest-skills/recon-subdomain"><img src="https://agentmods.dev/badge/skills/crazymarky/pentest-skills/recon-subdomain/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/crazymarky/pentest-skills/recon-subdomain"><img src="https://agentmods.dev/badge/skills/crazymarky/pentest-skills/recon-subdomain.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00054 | $0.02715 |
| Opus 5 | $0.00027 | $0.01358 |
| Sonnet 5 | $0.00011 | $0.00543 |
| Haiku 4.5 | $0.00005 | $0.00271 |
Grade A, and why
recon-subdomain scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 13d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
curl -s "https://crt.sh/?q=%.example.com&output=json" | \ How it starts
The opening of the file, as written. The whole thing — 418 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Subdomain Enumeration / DNS Reconnaissance
Authorization Warning
IMPORTANT: Subdomain enumeration without proper authorization may violate terms of service. Always ensure you have:
- Written permission from the target domain owner
- Defined scope of authorized testing
- Legal compliance with local regulations
Prerequisites
Required tools that must be installed on your system:
- subfinder -
go install -v github.com/projectdiscovery/subfinder/v2/cmd/subfinder@latest - dnsx -
go install -v github.com/projectdiscovery/dnsx/cmd/dnsx@latest
Optional tools:
- amass -
go install -v github.com/owasp-amass/amass/v4/cmd/amass@latest - assetfinder -
go install github.com/tomnomnom/assetfinder@latest - puredns -
go install github.com/d3mondev/puredns/v2@latest
Quick Start
Most commonly used commands for subdomain enumeration:
Fast Subdomain Discovery (Subfinder)
subfinder -d example.com -o subs.txt
Subdomain Discovery + DNS Resolution
subfinder -d example.com -silent | dnsx -silent -resp > resolved_subs.txt
Comprehensive Subdomain Enumeration (Amass)
amass enum -passive -d example.com -o amass_subs.txt
Multiple Tools Combined
subfinder -d example.com -silent | tee subs1.txt && \
assetfinder --subs-only example.com | tee subs2.txt && \
cat subs1.txt subs2.txt | sort -u > all_subs.txt
Common Scenarios
Scenario 1: Quick Passive Subdomain Discovery
When you need fast subdomain discovery without direct interaction:
subfinder -d example.com -o subs.txt
Parameters:
-d example.com- Target domain-o subs.txt- Output file-silent- Suppress stderr output (optional)
Example:
subfinder -d target.com -o target_subs.txt
subfinder -d target.com -silent | head -20
Scenario 2: Active Subdomain Enumeration
When you need comprehensive active enumeration:
amass enum -active -d example.com -o amass_active.txt
What ships with it
11 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- assets/resolvers.txt 655 B
- assets/subdomains-top5k.txt 4.8 KB
- assets/wildcard-test.txt 566 B
- references/amass_guide.md 1.7 KB
- references/dns_techniques.md 4.8 KB
- references/dnsx_guide.md 2.0 KB
- references/subfinder_guide.md 1.6 KB
- scripts/filter_resolved.py 3.0 KB runs code
- scripts/merge_subdomains.py 3.3 KB runs code
- scripts/subdomain_stats.py 3.6 KB runs code
- scripts/subdomain_storage.py 2.8 KB runs code
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 13d ago First seen · 418 lines · 54 tokens per session scan A 56b1e4f0bbfa
recon-subdomain is a skill published in the GitHub repository crazyMarky/pentest-skills (308 stars, last pushed 3mo ago), licensed Apache-2.0. It adds 54 tokens to every session and 2,715 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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