ctf-skills is a collection of agent instructions for solving capture-the-flag security challenges, including web exploitation, binary vulnerabilities, cryptography, reverse engineering, forensics, and OSINT. It is intended for agents and people working through CTF problems, and its skills can be loaded into supported coding-agent workflows.
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 ljagiello/ctf-skills --skill ctf-osintgit clone --depth 1 https://github.com/ljagiello/ctf-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/ljagiello/ctf-skills/ctf-osint)<a href="https://agentmods.dev/skills/ljagiello/ctf-skills/ctf-osint"><img src="https://agentmods.dev/badge/skills/ljagiello/ctf-skills/ctf-osint/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/ljagiello/ctf-skills/ctf-osint"><img src="https://agentmods.dev/badge/skills/ljagiello/ctf-skills/ctf-osint.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk warn
- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to high
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- high YARA Match · line 176 YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).Fix: Remove offensive tool references and exploit code. Legitimate agent skills should not contain penetration testing tools, exploit frameworks, or reconnaissance utilities.
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 | $0.00065 | $0.02313 |
| Opus 5 | $0.00032 | $0.01156 |
| Sonnet 5 | $0.00013 | $0.00463 |
| Haiku 4.5 | $0.00006 | $0.00231 |
Grade A, and why
ctf-osint 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 11d 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.
apt install whois dnsutils nmap libimage-exiftool-perl imagemagick curl Copies of this mod
3 near-identical copies found in the catalogue:
- ctf-osint — 100% identical, 0 lines differ
- ctf-osint — 92% identical, 64 lines differ
- fieldops-ctf-osint — 86% identical, 27 lines differ
How it starts
The opening of the file, as written. The whole thing — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CTF OSINT
Quick reference for OSINT CTF challenges. Each technique has a one-liner here; see supporting files for full details.
Prerequisites
Python packages (all platforms):
pip install shodan Pillow
Linux (apt):
apt install whois dnsutils nmap libimage-exiftool-perl imagemagick curl
macOS (Homebrew):
brew install whois bind nmap exiftool imagemagick curl
Additional Resources
- social-media.md - Twitter/X (user IDs, Snowflake timestamps, Nitter, memory.lol, Wayback CDX), Tumblr (blog checks, post JSON, avatars), BlueSky search + API, Unicode homoglyph steganography, Discord API, username OSINT (namechk, whatsmyname, Osint Industries), username metadata mining (postal codes), platform false positives, multi-platform chains, Strava fitness route OSINT
- geolocation-and-media.md - Image analysis, reverse image search (including Baidu for China), Google Lens cropped region search, reflected/mirrored text reading, geolocation techniques (railroad signs, infrastructure maps, MGRS), Google Plus Codes, EXIF/metadata, hardware identification, newspaper archives, IP geolocation, Google Street View panorama matching, What3Words micro-landmark matching, Google Maps crowd-sourced photo verification, Overpass Turbo spatial queries, music-themed landmark geolocation with key encoding
- web-and-dns.md - Google dorking (including TBS image filters), Google Docs/Sheets enumeration, DNS recon (TXT, zone transfers), Wayback Machine, FEC research, Tor relay lookups, GitHub repository analysis, Telegram bot investigation, WHOIS investigation (reverse WHOIS, historical WHOIS, IP/ASN lookup), fake service banner detection via nmap fingerprinting
When to Pivot
- If you already have the files or packets locally and now need extraction or carving, switch to
/ctf-forensics. - If the task becomes active exploitation of a live HTTP service, switch to
/ctf-web. - If you uncover malware samples, beacons, or suspicious binaries during attribution, switch to
/ctf-malware.
What ships with it
3 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.
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.
- 11d ago First seen · 193 lines · 65 tokens per session scan A a78f55e0162d
ctf-osint is a skill published in the GitHub repository ljagiello/ctf-skills (3,234 stars, last pushed 17d ago), licensed MIT. It adds 65 tokens to every session and 2,313 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.
Other skills, from other repositories
xiaohongshu-search-full
Search Xiaohongshu (XHS / RedNote) notes by keyword with full field extraction including body text, topics/tags, image list URLs, video stream URL, publish timestamp, and all engagement stats (likes, collects, comments, shares). Supports all page filter options: sort order (general, latest, most liked, most commented…
x-tweet-by-conversation
Collects every tweet in an X (Twitter) conversation thread given a conversation id (root tweet id) — the focal tweet plus all replies, sub-replies, and quote chains — and returns normalized per-tweet data with text, author, engagement counts, media, hashtags, mentions, inreplyto mapping, and cursor for pagination. Use…
amazon-reviews-api-skill
This skill helps users automatically extract Amazon product reviews via the Amazon Reviews API. Agent should proactively apply this skill when users express needs like getting reviews for Amazon product with ASIN B07TS6R1SF, analyzing customer feedback for a specific Amazon item, getting ratings and comments for a…
amazon-competitor-analyzer
Scrapes Amazon product data from ASINs using browseract.com automation API and performs surgical competitive analysis. Compares specifications, pricing, review quality, and visual strategies to identify competitor moats and vulnerabilities.
create-site
Creates a new Power Pages code site (SPA) using React, Angular, Vue, or Astro. Guides through the full process from initial concept to deployed site: requirements discovery, scaffolding, component planning, design, implementation, validation, and deployment. Use when the user wants to create, build, or scaffold a new…
add-cloud-flow
Integrates Power Automate cloud flows into a Power Pages site. Lists available flows, suggests relevant ones based on intent, identifies scenarios and web roles, creates metadata files, and generates client-side code to call flows. Handles both new flow registration and adding already-registered flows to additional…