domain-investigation

domain-investigation is a skill for Claude Code, Codex from Liberty91LTD/cti-skills. It costs 90 tokens per session (2,140 once invoked), scanned A, original, MIT.

A security investigation workflow for checking a domain or hostname across several threat-intelligence services.

In plain words
What is it for?
It helps investigate suspicious domains, combine findings, rate the evidence, and identify related indicators for follow-up.
Why use it?
It brings reputation, DNS, hosting, scan, and ransomware-claim checks into one investigation instead of requiring separate lookups.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps investigate suspicious domains, combine findings, rate the evidence, and identify related indicators for follow-up.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/liberty91ltd/cti-skills/domain-investigation
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 Liberty91LTD/cti-skills --skill domain-investigation
Clone the repo
git clone --depth 1 https://github.com/Liberty91LTD/cti-skills

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.

agentmods badge for domain-investigation

README.md
[![agentmods](https://agentmods.dev/badge/skills/liberty91ltd/cti-skills/domain-investigation/github.svg)](https://agentmods.dev/skills/liberty91ltd/cti-skills/domain-investigation)
Your own site
<a href="https://agentmods.dev/skills/liberty91ltd/cti-skills/domain-investigation"><img src="https://agentmods.dev/badge/skills/liberty91ltd/cti-skills/domain-investigation/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.

agentmods 80×15 button for domain-investigation

Your own site · 80×15
<a href="https://agentmods.dev/skills/liberty91ltd/cti-skills/domain-investigation"><img src="https://agentmods.dev/badge/skills/liberty91ltd/cti-skills/domain-investigation.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 90 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,140 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00090 $0.02140
Opus 5 $0.00045 $0.01070
Sonnet 5 $0.00018 $0.00428
Haiku 4.5 $0.00009 $0.00214

Measured 12d ago against content hash 39a822fcdad8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

domain-investigation scanned grade A with 0 findings 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 12d 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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/domain-investigation/SKILL.md · 182 lines

How it starts

The opening of the file, as written. The whole thing — 182 lines — stays where its author put it; the contents beside it link to each section on GitHub.

domain-investigation

Investigate a domain or hostname end-to-end. Chain lookup-* skills, consolidate, prioritize follow-up IOCs, and return a rated investigation summary.

This skill invokes: /lookup-liberty91 (first-party — run first), /lookup-virustotal, /lookup-urlscan, /lookup-shodan, /lookup-otx, /lookup-ransomwarelive, optionally /lookup-censys, optionally /lookup-reversinglabs (network threat-intel from RL malware corpus), optionally /lookup-crowdstrike (IOC reputation + actor/malware links), optionally /lookup-misp and/or /lookup-opencti (internal correlation), optionally /lookup-sentinel (exposure check in your own telemetry), then /source-assessment, /tlp-guide, /confidence-levels.

When to invoke

  • User asks to investigate, check, or enrich a domain / hostname
  • User pastes a suspicious domain and asks "what is this?"
  • /url-investigation hands off the parent domain for deeper context
  • /ip-investigation surfaced a hostname worth investigating

Inputs

indicator: <domain or hostname>
context: <optional>
tlp_ceiling: <optional, default AMBER>

Procedure

1. Validate + triage

  • Confirm it parses as a valid domain (reject IPs, URLs — route those to the right skill)
  • Check for obvious false positives (top 1M domains, your own infrastructure)
  • Check data/iocs/ for prior enrichment

2. Parallel lookups

/lookup-virustotal domain <value>    # reputation + WHOIS-ish
/lookup-urlscan domain <value>       # existing scans (search, not submit)
/lookup-shodan domain <value>        # DNS resolve + host fingerprint of the resolved IP
/lookup-otx domain <value>           # community pulses + passive DNS
/lookup-ransomwarelive search --q <org-candidate>   # victim-status sweep

For the ransomware.live sweep, derive an org-candidate from the domain by stripping the public suffix and any common subdomains (www.acme-corp.comacme-corp or acme corp). If the apex contains a hyphen or dot, also try the first label alone. The PRO tier returns the full match set in one call (no pagination), so two candidate queries cost at most two of the 3000-call daily budget.

Read the full file on GitHub · 182 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.

  1. 12d ago First seen · 182 lines · 90 tokens per session scan A 39a822fcdad8

Subscribe to this mod's changes

domain-investigation is a skill published in the GitHub repository Liberty91LTD/cti-skills (18 stars, last pushed 1mo ago), licensed MIT. It adds 90 tokens to every session and 2,140 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.