email-security

email-security is a skill for Claude Code from ShulkwiSEC/bb-huge. It costs 73 tokens per session (2,861 once invoked), scanned A, original, MIT.

A checklist and workflow for reviewing how a domain's email systems authenticate messages, encrypt connections, handle relays, and expose users. It covers standards such as SPF, DKIM, and DMARC, which help receiving servers detect forged email.

In plain words
What is it for?
Assessing email domains, SMTP servers, contact forms, email APIs, password-reset flows, and protections against spoofed messages.
Why use it?
Weak email settings can allow spoofing, unauthorised relaying, insecure delivery, or user discovery. The audit identifies these weaknesses and provides remediation guidance.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter. Also seen: positional $N argument; mentions Claude Code; mentions OpenCode.

Good fit Assessing email domains, SMTP servers, contact forms, email APIs, password-reset flows, and protections against spoofed messages.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/shulkwisec/bb-huge/email-security
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 ShulkwiSEC/bb-huge --skill email-security
Clone the repo
git clone --depth 1 https://github.com/ShulkwiSEC/bb-huge

Made for: Claude Code.

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 email-security

README.md
[![agentmods](https://agentmods.dev/badge/skills/shulkwisec/bb-huge/email-security/github.svg)](https://agentmods.dev/skills/shulkwisec/bb-huge/email-security)
Your own site
<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/email-security"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/email-security/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 email-security

Your own site · 80×15
<a href="https://agentmods.dev/skills/shulkwisec/bb-huge/email-security"><img src="https://agentmods.dev/badge/skills/shulkwisec/bb-huge/email-security.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 73 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,861 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 $0.00073 $0.02861
Opus 5 $0.00036 $0.01430
Sonnet 5 $0.00015 $0.00572
Haiku 4.5 $0.00007 $0.00286

Measured 7d ago against content hash c6a4e8e01a70, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

email-security 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 7d 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/curated/email-security/SKILL.md · 259 lines

How it starts

The opening of the file, as written. The whole thing — 259 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Email Infrastructure Security Audit

You are an expert email security auditor. Your goal: comprehensively assess the email infrastructure of a target domain — authentication mechanisms (SPF/DKIM/DMARC), transport security (STARTTLS/MTA-STS), relay configuration, spoofing resilience, and user enumeration — and report all weaknesses with remediation guidance.

Request: $ARGUMENTS


CHAIN COMMITMENTS — DECLARE BEFORE STARTING

Read this before executing any workflow phase. Commit to MANDATORY chains before your first tool call.

Trigger Chain Mandatory? Claude Code opencode
After session(action="complete") /gh-export OPTIONAL — user request only Skill(skill="gh-export") cat ~/.config/opencode/commands/gh-export.md
SMTP/STARTTLS weakness found /ssl-tls-audit OPTIONAL Skill(skill="ssl-tls-audit") cat ~/.config/opencode/commands/ssl-tls-audit.md
Email credentials found /credential-audit OPTIONAL Skill(skill="credential-audit") cat ~/.config/opencode/commands/credential-audit.md
Architecture review requested /threat-modeling OPTIONAL Skill(skill="threat-modeling") cat ~/.config/opencode/commands/threat-modeling.md

Logging: Before invoking any skill above, call session(action="set_skill", options={"skill":"<name>","reason":"<why>","chained_from":"<this-skill>"}) — this writes the SKILL_CHAIN entry to pentest.log.


Tools Available

Tool Use for
session(action="start", options={...}) Define target, scope, depth, and hard limits — always call this first
session(action="complete", options={...}) Mark the scan done and write final notes
kali(command=...) Kali tools: swaks, dig, nmap, smtp-user-enum, openssl s_client
scan(tool="nmap", ...) SMTP service detection and NSE scripts
http(action="request", ...) Check MTA-STS policy, web-based mail config
report(action="finding", data={...}) Log confirmed vulnerabilities to findings.json
report(action="diagram", data={...}) Save email infrastructure diagrams
report(action="dashboard", data={"port": 7777}) Serve dashboard.html at localhost:7777
report(action="note", data={...}) Write reasoning notes to session log

Read the full file on GitHub · 259 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. 7d ago First seen · 259 lines · 73 tokens per session scan A c6a4e8e01a70

Subscribe to this mod's changes

email-security is a skill published in the GitHub repository ShulkwiSEC/bb-huge (22 stars, last pushed 2mo ago), licensed MIT. It adds 73 tokens to every session and 2,861 once invoked, about $0.0004 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 2026-09-03.

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