email-domain-security SKILL.md skillA
email-domain-security from elementalsouls/claude-osint is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add elementalsouls/claude-osint/email-domain-security@v1Pins v1 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- elementalsouls/claude-osint
- Path
skills/email-domain-security/SKILL.md- Versions recorded
- 3
- Latest version
- v1, committed Aug 24, 2026
- First version recorded
- Aug 6, 2026
- Size
- 47,075 bytes
- Repository stars
- 2,831
- License
- MIT
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…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Email Domain Security — Spoofability Verdict & SPF Supply-Chain Analysis > Companion skills: **`offensive-osint` §16.14** (raw record-fetch recipes — dig/PowerShell one-liners for SPF/DMARC/DKIM/BIMI/MTA-STS/TLS-RPT/DNSSEC/CAA, the MX→IdP inference table, the DMARC reporting-vendor table). **`osint-methodology`** (confidence levels, output format, severity rubric this skill inherits). Fetch the records with §16.14 first; bring the raw TXT text here for the verdict. This skill does not re-list what a record *is* — it reasons about what a domain's *combination* of records actually lets an attacker do. ## 0. When to Use / When NOT **Use this skill when:** - Asked to audit spoof feasibility, produce an email-spoofability verdict, or explain "is domain X spoofable." - You already have raw SPF/DMARC TXT text (via `offensive-osint` §16.14 or your own `dig`) and need the *verdict*, not just the record dump. - Investigating an SPF PermError, a long or unusual include chain, or a dead `include:` target. - Writing a client-facing finding that has to survive the pushback "we have SPF `-all`, why is this flagged?" …
Read the whole file at its exact version.
How to install
mdr add elementalsouls/claude-osint/email-domain-security@sha256:47dfa12c7dff9999The line at the top of this page pins the label v1, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_kexj62am5r6gbhng)
5 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Aug 6, 2026 and Aug 24, 2026, about one every 9 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| v1 latest | 2026-08-24 | f4acf9e | 47,075 B | A | view · diff |
| v1 | 2026-08-10 | 66ffd91 | 47,020 B | A | view · diff |
| v1 | 2026-08-06 | e0fef8b | 47,002 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (47075 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
elementalsouls/claude-osint · 2,831 stars · license MIT · pushed 2026-10-09 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_kexj62am5r6gbhng GET https://markdownregistry.com/api/v1/resolve?ref=elementalsouls/claude-osint/email-domain-security GET https://markdownregistry.com/api/v1/blob/47dfa12c7dff999930789222a6efc7bfbcf01a4adc66210892fadb50582e47ba
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
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