A checklist for passive reconnaissance, which means collecting information about a target without actively attacking it. It covers DNS, WHOIS domain-registration records, subdomains, public certificates, IP details, and search-engine queries.

Use it at the start of an authorized security engagement to find mail and name servers, subdomains, related IP addresses, certificate names, network ownership, location data, and exposed public files or login pages.

It organizes early research so important public information about a domain or network is less likely to be missed.

recon-phase — Skill for Claude Code and Codex by s0ld13rr/pentestcode

Install

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.

Any agent

npx skills add s0ld13rr/pentestcode --skill recon

Clone the repo

git clone --depth 1 https://github.com/s0ld13rr/pentestcode

Made for: Claude Code, Codex.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/s0ld13rr/pentestcode/recon/github.svg)](https://agentmods.dev/skills/s0ld13rr/pentestcode/recon)

Your own site

<a href="https://agentmods.dev/skills/s0ld13rr/pentestcode/recon"><img src="https://agentmods.dev/badge/skills/s0ld13rr/pentestcode/recon/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/s0ld13rr/pentestcode/recon"><img src="https://agentmods.dev/badge/skills/s0ld13rr/pentestcode/recon.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 683 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

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	$0.00049	$0.00683
Opus 5.5	$0.00020	$0.00273
Sonnet 5.5	$0.00010	$0.00137
Haiku 4.5	$0.00005	$0.00068

Measured 14d ago against content hash faad6cb4a429, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

recon-phase 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 14d 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.

- **Cert transparency**: `curl -s "https://crt.sh/?q=%25.target.com&output=json" | jq -r '.[].name_value' | sort -u` — often finds forgotten subdomains + internal hostnames in CN fields

skills/phases/recon/SKILL.md · 32 lines

How it starts

The opening of the file, as written. The whole thing — 32 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Reconnaissance — Passive FIRST, then Active

Rule: exhaust PASSIVE before touching the target. Passive leaves no logs on target infra; active does.

Passive

DNS/subdomains: subfinder -d target.com -silent, amass enum -passive -d target.com, assetfinder --subs-only target.com
Cert transparency: curl -s "https://crt.sh/?q=%25.target.com&output=json" | jq -r '.[].name_value' | sort -u — often finds forgotten subdomains + internal hostnames in CN fields
WHOIS/RDAP: registrar, name servers, historical contacts (who.is, rdap.org)
Net blocks: whois -h whois.radb.net -- '-i origin ASXXXX' → prefix list, then validate with asnmap
Shodan/Censys: exposed services, banners, SSL certs (Shodan cert search pivots to sibling hosts on same org), leaked .env/.git indexes
Google dorks: site:target.com filetype:xlsx, site:target.com inurl:admin, intitle:"index of" site:target.com, site:target.com ext:env | ext:sql | ext:bak
Code leaks: GitHub/GitLab search org:target, target.com password, secret scanning (trufflehog/gitleaks on found repos)
Social: LinkedIn (org chart, tech stack, employees for phishing/spray), job ads (tech in use), Wayback Machine for dead endpoints still live internally

Active (in-scope domains/IPs ONLY)

DNS brute + zone transfer: dig axfr target.com @NS, gobuster dns -d target.com -w wordlist
Fingerprint: httpx -l subs.txt -status-code -title -tech-detect -favicon-hash — favicon hash pivots to Shodan http.favicon.hash:<mmh3>
ASN/IP expansion: resolve all found hosts → new IPs → re-check every IP against scope with scope_check
WAF detect: wafw00f https://target.com — affects scan tuning later

Gotchas

Subdomain takeover check immediately: dangling CNAME (npm/github/azure/s3) → subjack/nuclei -t takeovers/. It's recon AND a finding.
A cert in CT logs is NOT proof the host is in scope. Validate + scope_check before any active probe.
Record everything into the engagement state (state_update): hosts, domains, org relationships. Later phases consume this — a host found in recon but never scanned is the classic miss.
Diff CT logs against live DNS: dead names may still resolve on INTERNAL resolvers (VPN/recon from inside).

Read the full file on GitHub · 32 lines

Changes

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.

14d ago Changed · -50 lines · +14 tokens per session faad6cb4a429
2mo ago First seen · 82 lines · 35 tokens per session scan A c63ef0cc0891

Subscribe to this mod's changes

recon-phase is a skill published in the GitHub repository s0ld13rr/pentestcode (929 stars, last pushed yesterday), licensed MIT. It adds 49 tokens to every session and 683 once invoked, about $0.0002 per session on Opus 5.5. 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.

Security ai-agents ai-security ai-security-tool anthropic gpt openai recon

recon-phase next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
recon-phases0ld13rr/pentestcode	Skill	929	yesterday	MIT	A	49	Claude Code, Codex
lictor-security-checkRaffa-jarrl/Lictor-AI	Skill	18	3mo ago	Apache-2.0	A	135	Claude Code
lictor-rotateRaffa-jarrl/Lictor-AI	Skill	18	3mo ago	Apache-2.0	A	80	Claude Code
lictor-explainRaffa-jarrl/Lictor-AI	Skill	18	3mo ago	Apache-2.0	A	56	Claude Code
openai-patternschandrudp29/skillhub	Skill	14	4mo ago	MIT	A	31	Claude Code, Codex
lictor-fix-itRaffa-jarrl/Lictor-AI	Skill	18	3mo ago	Apache-2.0	B	75	Claude Code
html-artifactslangchain-ai/open-swe	Skill	11k	yesterday	MIT	A	52	Claude Code, Codex

recon-phase