deliverability-audit
Skill13 starsChanged 22 days agoMITView on GitHub
Use this skill when cold emails land in spam or reply rates suddenly drop: \"audit my email deliverability\", \"why are my emails going to spam\", \"check my sending setup\", \"open and reply rates fell off a cliff\". Checks domain setup (SPF, DKIM, DMARC, tracking domain), sending volume and patterns, bounce and complaint rates, list quality, content risks and inbox placement, ranks the problems by impact, and produces a fix plan with a recovery timeline.
1 other project uses a version of this.
Adopted by
Most recently taken up by
- ilya-a11y/growthband-outbound-skillstheir own version, first seen Apr 23, 2026
Other versions1 project uses a version of this.
Word for word · 0
None found.
Edited · 0
None found.
Wrote their own version · 1
- ilya-a11y/growthband-outbound-skills★ 13same name
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
In this repository77 other files it gives its agents.
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- The first 60 shown.
The file
We split this skill into the rules it gives an agent
5 rules. About 0 are common, 5 are distinctive, and 0 are very specific to this project.
≈0
Common · estimate
Many files like this have a rule of this kind.
≈5
Distinctive · estimate
This author's own choices. Worth a look.
0
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Distinctive: line 16
Use this when results drop and the copy has not changed.
- Distinctive: line 69
MUST check authentication before content.
- Distinctive: line 70
MUST recommend pausing any mailbox with bounces over 5% or complaints over 0.3%.
- Distinctive: line 71
NEVER recommend tactics that disguise the sender or evade provider filters (hidden text, misleading headers, rotating look-alike domains to …
- Distinctive: line 72
NEVER change DNS records without the user's approval.
≈ “Common” is an estimate: at least 1 in 5 of the 350,495 skill files we read have a rule of the same kind, not the same words. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
Use this when results drop and the copy has not changed. Most "the campaign stopped working" problems are deliverability problems: the emails are not being seen.
Inputs
- Sending domains and the number of mailboxes on each.
- DNS records (SPF, DKIM, DMARC, MX) or permission to look them up.
- Metrics per mailbox: volume per day, bounce rate, reply rate, spam complaints, over the last 30-60 days.
- Two or three sample emails as sent.
The play
1. Check authentication
SPF, DKIM and DMARC must exist, align with the From domain, and pass. Large mailbox providers require all three for bulk senders and reject or junk unauthenticated mail. Read references/audit-checklist.md for the full checklist and what each failure looks like.
2. Check the domain strategy
- Cold email from the primary company domain risks the domain that carries invoices and customer mail. Use separate, aged sending domains that redirect to the main site.
- Each sending domain has 2-5 mailboxes, not 20.
- A custom tracking domain, or no open and click tracking at all for cold outreach.
3. Check volume and pattern
- Per mailbox: 30-50 cold emails a day after warm-up is a common safe range.
- Sending spread through the working day, not in one burst.
- Sudden jumps in volume (doubling overnight) are a common trigger for filtering.
4. Check list quality
Bounce rate over 2-3% means a list problem. Spam complaints over 0.1% (one in a thousand) are a red flag; 0.3% is the threshold large providers warn about. Old lists, purchased lists and catch-all-heavy lists are usual causes.
5. Check content
Links (especially link shorteners), images, attachments, tracking pixels, spam-pattern words and heavy HTML all add risk. Cold email should be plain text-looking with zero or one link.
6. Test placement
Send to a seed set of test inboxes across providers, or ask friendly contacts to check folders. Separate "inbox", "promotions or other" and "spam".
7. Rank and fix
Order fixes by impact: authentication failures and blacklisting first, then list quality, then volume, then content.
Output format
Verdict: healthy / at risk / damaged
Problems (ranked): <issue - evidence - impact - fix>
Recovery plan: <week by week>
Monitor weekly: bounce %, complaint %, reply rate per mailbox, placement testWhat good looks like
- Diagnosis by mailbox and domain, not just campaign averages; one bad mailbox can hide inside a healthy average.
- The fix plan pauses damaged mailboxes rather than pushing more volume through them.
- The common mistake is rewriting copy for weeks while the real cause is a missing DMARC record or a 6% bounce rate.
Rules
- MUST check authentication before content.
- MUST recommend pausing any mailbox with bounces over 5% or complaints over 0.3%.
- NEVER recommend tactics that disguise the sender or evade provider filters (hidden text, misleading headers, rotating look-alike domains to dodge complaints).
- NEVER change DNS records without the user's approval.
Example prompts
- "Our reply rate went from 4% to 0.5% in two weeks. Audit our deliverability."
- "Here are our DNS records and per-mailbox stats. What's wrong?"
- "Build a deliverability checklist we run before every campaign."
Does it work?
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Your trail
Files you open will collect here, so you can find them again.
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Now do this for your own.
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