Claude skill
Inbox Checker
Is this domain burned?
You reach for this when sending has already gone wrong: replies stopped, or mail started landing in spam, and you need to know whether the domain is recoverable or spent. It runs every reputation and authentication check at once and answers the question you actually asked before offering any advice about fixing it.
What it runs
- Blacklists — Whether the domain or its IP is listed on the major blocklists
- SURBL — Whether the domain itself is flagged in message bodies, which survives changing servers
- SPF, DKIM, DMARC — Whether receivers can still verify you, and whether enforcement is on
- MX — Whether mail is still routed where you think it is
- Nameservers — Who controls DNS, and whether that changed
- Registration age — How much sending history the domain can plausibly have
- Google hosting — Whether the domain is tied to a Google Workspace account
What you get back
- One verdict: burned, at risk, or clean
- The evidence behind it, with a link to re-run each check yourself
- If burned, the honest answer, which is that reputation attaches to the domain and the fix is a different one
- If at risk, the fixes in order of what each is costing you
Install it
One file, from GitHub. It calls the free WarmInboxes API, so there is no key and nothing to sign up for.
mkdir -p ~/.claude/skills/inbox-checker curl -sL https://raw.githubusercontent.com/Huz-ai-fa/warminboxes-claude-skills/main/inbox-checker/SKILL.md -o ~/.claude/skills/inbox-checker/SKILL.md
Then just ask
You do not name the skill. Its description tells Claude when it applies.
- “Is acme.com safe to send from?”
- “My replies dropped off a cliff yesterday, check my sending domain”
- “I am taking over a client’s cold email setup, is this domain burned?”
Every answer cites the check behind it, so anything Claude tells you can be re-run by hand. A clean result is reported clean, with nothing to buy.