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 S3YED/appie-kit --skill email-authenticationgit clone --depth 1 https://github.com/S3YED/appie-kitWrote 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/s3yed/appie-kit/email-authentication)<a href="https://agentmods.dev/skills/s3yed/appie-kit/email-authentication"><img src="https://agentmods.dev/badge/skills/s3yed/appie-kit/email-authentication/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/s3yed/appie-kit/email-authentication"><img src="https://agentmods.dev/badge/skills/s3yed/appie-kit/email-authentication.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00036 | $0.00662 |
| Opus 5 | $0.00018 | $0.00331 |
| Sonnet 5 | $0.00007 | $0.00132 |
| Haiku 4.5 | $0.00004 | $0.00066 |
Grade A, and why
email-authentication 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 9d 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.
How it starts
The opening of the file, as written. The whole thing — 59 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Email Authentication (SPF / DKIM / DMARC)
Use when diagnosing bounced emails, spam delivery, or setting up mail authentication for a domain.
Diagnosis workflow
When mail from domain A to domain B bounces but mail from Gmail to B works:
- Run the verification script (see references/dns-checks.md) on domain A first
- Missing SPF is the most common cause — fix it before investigating DKIM
- Namecheap Private Email bounce
JFE030050("address not found") is usually SPF rejection in disguise, even when the mailbox exists - After fixes, wait 1-2 hours for DNS propagation, then test with a real email
Provider-specific SPF records
| Provider | SPF record |
|---|---|
| Google Workspace | v=spf1 include:_spf.google.com ~all |
| Namecheap Private Email | v=spf1 include:spf.privateemail.com ~all |
Host is always @ (root domain). Type is always TXT.
DKIM
Google Workspace: Enable in Google Admin → Apps → Gmail → Authenticate email. Default selector is google, so the record goes at google._domainkey.<domain>.
Namecheap Private Email: Enable in Namecheap dashboard → Private Email → Manage domain → Email Security → Generate DKIM. Namecheap uses selector privateemail (NOT default), so the record goes at privateemail._domainkey.<domain>. Copy the Host and DNS Record fields from the dashboard — the Public Key field is informational only and already included in the DNS Record.
DMARC
Start with monitor mode for all new domains:
v=DMARC1; p=none; rua=mailto:<report-address>
Host is _dmarc. After a few weeks of monitoring with no issues, tighten to p=quarantine then p=reject.
For Weblyfe client domains, use rua=mailto:info@<client-domain> unless they have a dedicated DMARC parser.
Verification
After adding records, verify with dig (see references/dns-checks.md). A passing set has:
- SPF TXT record at root domain
- DKIM TXT record at
<selector>._domainkey.<domain> - DMARC TXT record at
_dmarc.<domain>
All three must be present for full authentication. Mail sent with SPF+DKIM+DMARC passing virtually never lands in spam.
What ships with it
1 file 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.
- 9d ago First seen · 59 lines · 36 tokens per session scan A e09b0165f00f
email-authentication is a skill published in the GitHub repository S3YED/appie-kit (9 stars, last pushed 17d ago), licensed MIT. It adds 36 tokens to every session and 662 once invoked, about $0.0002 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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