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Email Domain Security

Email Domain Security is an agent skill (a SKILL.md file) from elementalsouls/Claude-OSINT. Rigorous, defensible email-spoofability verdict and SPF supply-chain risk analysis computed from published DNS alone. It works with Claude Code and has 2,871 GitHub stars across a repository of 3 listed skills.

github.com/elementalsouls/Claude-OSINT/skills/email-domain-security (opens in a new tab)

Data as of from the GitHub API; description from the skill's SKILL.md. Report an error

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Add this skill

Claude

Claude Code loads skills from ~/.claude/skills/ (all projects) or .claude/skills/ (one project):

git clone --depth 1 https://github.com/elementalsouls/Claude-OSINT.git
cp -r Claude-OSINT/skills/email-domain-security ~/.claude/skills/email-domain-security   # personal, or .claude/skills in a project

In the Claude apps, zip the email-domain-security folder and upload it under Customize > Skills > + > Upload a skill (code execution must be on).

ChatGPT / Codex

Codex reads skills from .agents/skills/ in a repo or ~/.agents/skills/ for every project:

git clone --depth 1 https://github.com/elementalsouls/Claude-OSINT.git
cp -r Claude-OSINT/skills/email-domain-security .agents/skills/email-domain-security   # repo; ~/.agents/skills for all projects

Standalone skills also load in the ChatGPT desktop app.

Cursor

Cursor loads skills from .cursor/skills/ (or ~/.cursor/skills/) and also reads .claude/skills/:

git clone --depth 1 https://github.com/elementalsouls/Claude-OSINT.git
cp -r Claude-OSINT/skills/email-domain-security .cursor/skills/email-domain-security   # project; ~/.cursor/skills for all projects

Source (checked Oct 7, 2026): code.claude.com/docs/en/skills (opens in a new tab), support.claude.com/en/articles/12512180-using-skills-in-claude (opens in a new tab), learn.chatgpt.com/docs/build-skills (opens in a new tab), cursor.com/docs/context/skills (opens in a new tab)

What this skill does

Rigorous, defensible email-spoofability verdict and SPF supply-chain risk analysis computed from published DNS alone. Deepens the record-level SPF/DMARC/DKIM/BIMI/MTA-STS/DNSSEC fetch recipes in the offensive-osint arsenal (§16.14) with the reasoning that section doesn't do: a priority-ordered composite verdict for whether an attacker can actually land header-From-spoofed mail in an inbox, and by which vector (exact-domain vs subdomain) — grounded in the single most-misunderstood distinction…

More skills in elementalsouls/Claude-OSINT

3 skills are listed from this repository.

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All Security

FAQ

Email Domain Security FAQ

Still curious? Email info@appsgit.com.

How do I install the Email Domain Security skill?

Copy the email-domain-security folder (the one containing SKILL.md) into ~/.claude/skills/ for Claude Code, .agents/skills/ for Codex or .cursor/skills/ for Cursor. The agent picks it up automatically when a task matches its description.

Is the Email Domain Security skill free?

Yes. The repository is open source under the MIT license.

Is Email Domain Security maintained?

The repository's most recent commit was on Oct 20, 2026. appsgit only lists skills from repositories with a commit in the last six months.