Email Spam Tester
Test an email before it goes out: a one-time address, a spam score, 41 checks with RFC citations and a fix plan.
Hosted MCP Server
npx add-mcp 'https://email-spam-tester.com/mcp'Installs into Claude Code, Codex, Cursor and more
Documentation
Skipped is not passed.
Your agent should know that.
Drop it into your project
The file is plain Markdown. Connect the MCP server first, then give the agent this.
https://email-spam-tester.com/mcp
- 01 Download SKILL.md It is one file with no scripts in it.
- 02 Save it in your project In Claude Code that is.claude/skills/mail-vet/SKILL.md. Other clients have their own place for the same thing.
- 03 Ask for a test The agent now runs the loop by itself: address, real send, report, fix, send again.
mkdir -p .claude/skills/mail-vetcurl -o .claude/skills/mail-vet/SKILL.md https://email-spam-tester.com/skill/SKILL.md
Without an agent
Two requests, no key. The first reserves the address, the second reads the report: 202 while nothing has arrived, 200 with everything once it has.
curl -sX POST 'https://email-spam-tester.com/api/v1/inbox?lang=en&utm_source=agent'
curl -s 'https://email-spam-tester.com/api/v1/tests/<slug>'
What to ask
Run the loop
Test this newsletter, fix what you can and tell me what only I can change.
Two fixes made. The DMARC record is yours to publish.
Sort the findings
Which findings in this report are DNS records and which are text you can edit? [report link]
Two are DNS records, one is copy I can change.
Be honest about gaps
Is this score complete, or did some checks not run? [report link]
Two checks could not run, so treat the score as optimistic.
Where it lives
Questions
Why does it want a real email instead of pasted text?
About half of the checks read what the sending platform adds: the DKIM signature, the path through its servers, the unsubscribe headers. Pasted text has none of those, so the model would be guessing.
What can the server see?
What you send to the test address. The raw message stays for an hour after it arrives and then only the report remains, at a link anyone with the slug can open. Test mail you would be fine showing a colleague, and read the privacy policy for the rest.
Is the score the same as on the website?
Yes. It is the same analysis and the same report page, so a run from a chat can be compared with one from the home page.
Do I need the skill if I have the MCP server?
No. The tools work without it. The skill saves you from explaining what the results mean.
What does the skill change?
It tells the agent when to test, how to read skip against pass, and which findings it cannot fix by editing text.
Where does it live in other clients?
Wherever your client keeps project rules. Paste the file there.