How is this different from just asking an AI to check if an email looks valid?

An AI model can only judge how an address is written. MailProbe asks the mail server of the domain, in real time and without sending anything, whether the mailbox exists. The skill then tells the agent how to act on the answer.

Which AI agents and platforms are compatible with MailProbe?

Any agent that loads SKILL.md skills and connects to an MCP server. The remote server needs a client that can send an Authorization header, such as Claude Code, Cursor or VS Code. The local mailprobe-mcp npm package serves the clients that start a server on the computer, such as Claude Desktop.

What external accounts or keys do I need to get started?

A MailProbe account and its API key. A new account starts with 100 credits. You set the key in the configuration of the MCP server, not in the conversation.

Is there a limit to how many emails I can verify at once?

20 addresses per call, and a call answers within about 55 seconds. The skill has the agent go through a longer list call after call, and points you to the batch screen of your MailProbe account above a few hundred addresses.

Does the skill handle 'catch-all' domains or protected Microsoft addresses?

Yes. Both come back as risky, and the skill has the agent say which case it is: a catch-all domain accepts every address, and Microsoft consumer domains (outlook.com, hotmail.com, live.com, msn.com) refuse probes, so risky there says nothing against the address. You decide what to keep.

MailProbe: verify email addresses from your agent

Example session with this skill installed

Check the addresses of ~/Desktop/tests/agensi-demo/contacts/signups.csv before I send the newsletter.

Read your context and instructions
Compiled the mailprobe
Generated the data export

I checked ~/Desktop/tests/agensi-demo/contacts/signups.csv with MailProbe. The file has 9 rows, which makes 8 distinct entries: Contact@MailProbe.dev repeats contact@mailprobe.dev. One entry is not a well-formed address, so 7 addresses were to be probed, 7 credits at most. Your balance was 782 credits, so I sent the list in one call.

Result: 1 valid, 4 invalid, 3 risky, 0 unknown.

Address	Status	Score	Why
jamal@tantaoui.com	valid	92	The mail server confirmed the mailbox
contact@mailprobe.dev	risky	77	Accepted by the mail server, but a role address (`contact@`)
marie.dupont@gmial.com	invalid	0	No mail server for gmial.com (`no_mx`). Suggestion: gmail.com
test@mailinator.com	risky	15	Disposable address on a catch-all domain (`accept_all`)
nobody-4821@mailprobe.dev	invalid	0	The mail server rejected the mailbox (550 5.1.1)
hello@no-such-domain-4821.com	invalid	0	No mail server for this domain (`no_mx`)
demo.4821.unknown@outlook.com	risky	65	outlook.com refuses probes (`provider_blocks_probe`)
not-an-address	invalid	0	Not a well-formed address (`invalid_syntax`)

Remove before sending (4): marie.dupont@gmial.com, nobody-4821@mailprobe.dev, hello@no-such-domain-4821.com and not-an-address.

One suggestion to confirm: marie.dupont@gmial.com looks like a typo of marie.dupont@gmail.com. I did not change it. The corrected address is another address, and verifying it costs 1 credit.

Three risky addresses, your call:

contact@mailprobe.dev: the mailbox exists. It is a role address, read by a team rather than by one person.
test@mailinator.com: a disposable address, on a domain that accepts every address. Nothing shows that someone reads it.
demo.4821.unknown@outlook.com: Microsoft consumer domains refuse probes, so this verdict says nothing against the address.

Credits: 7 used. The repeated address and the malformed entry were free. Balance: 775.

File: the results are in ~/Desktop/tests/agensi-demo/contacts/signups-verified.csv, with the address, status, score, reason and suggestion. signups.csv is unchanged.

Next steps:

Tell me whether to verify marie.dupont@gmail.com (1 credit).
Decide on the three risky addresses.
I can then write the list to send to, with only the addresses you keep.

A valid verdict says the mailbox accepts mail today. It does not say that the person agreed to receive the newsletter.

signups.csv

CSV · data export

Generated

Example file from a real run - the skill writes it into your workspace.

Connects securely to your tools. The creator never sees your data.

About this skill

This skill tells an AI agent how to use the tools of the official MailProbe MCP server, which checks in real time whether email addresses exist and can receive mail, without sending anything. The server gives the agent 2 tools. The skill gives it the judgement: how to read a result, what a call costs, and how to go through a list.

What the agent learns

How to read a result. Act on the status (valid, invalid, risky, unknown), say why an address is risky, tell an unknown worth a retry from one that will come back the same, and treat a typo suggestion as a suggestion.
What a call costs. One credit per address actually probed. The agent knows which cases are free, and that a retry costs again.
How to go through a list. Remove the repeats, count the credits before starting, send 20 addresses per call, keep the results in a new file, and report in numbers.
When to stop. Above a few hundred addresses, the batch screen of the MailProbe account is the right tool.

What you need

A MailProbe MCP server: the remote one at https://mailprobe.dev/mcp, or the local one, npx -y mailprobe-mcp, with Node.js 22 or later. Installation.
A MailProbe API key. A new account starts with 100 credits: mailprobe.dev.

Privacy

The addresses are sent to MailProbe, on servers in France, which keeps none of them. The skill itself makes no network call and runs no code: it is a single SKILL.md.

Source

MIT licence. Source and issues: github.com/jamalofski/mailprobe-mcp.

How to use

Skills on Agensi run inside your AI agent. Copy the prompt, paste it into your agent, and it connects to Agensi and installs this skill for you. If a payment is needed, your agent shows it to you first.

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MailProbe: verify email addresses from your agent