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MailerCheck for AI agents

MailerCheck verifies individual email addresses and entire mailing lists, reporting deliverability results and tracking verification credit balances for marketing teams. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.

Connect MailerCheckSee the 9 actions ↓
EmailAPI keyMCP + RESTmailercheck.com
AUDIT LOG · MAILERCHECKPOLICY: acme-support
09:41:07 · claude · u_8f2read
mailercheck.list_verification_lists
List Verification Lists✓ allowed · 212ms
09:41:08 · claude · u_8f2read
mailercheck.verify_email
Verify Email✓ allowed · 164ms
09:41:09 · claude · u_8f2write
mailercheck.create_verification_list
Create Verification List✓ approved · approved by user
09:41:12 · claude · u_8f2destructive
mailercheck.delete_verification_list
Delete Verification List✕ blocked · policy: deny
EVERY MAILERCHECK CALL, ON THE RECORD
01 · USE CASES

What agents do in MailerCheck.

01

Verify a single email

Check one email address for deliverability before it is added to a campaign.

02

Check results, read-only

Pull results from a completed list verification to see which addresses are safe to send to, a read-only lookup.

03

Check remaining credit balance

Look up remaining account credits before starting a large list verification job, so it does not run out mid-way.

02 · ACTIONS

9 MailerCheck actions, graded by risk.

Every MailerCheck action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.

read

6

Look things up. Allowed by default.

  • mailercheck.get_credit_balance
    Get Credit Balance
  • mailercheck.get_current_account
    Get Current Account
  • mailercheck.get_verification_list
    Get Verification List
  • mailercheck.list_verification_lists
    List Verification Lists
  • mailercheck.list_verification_results
    List Verification Results
  • mailercheck.verify_email
    Verify Email

write

2

Create and change things. Allow, or ask the user first.

  • mailercheck.create_verification_list
    Create Verification List
  • mailercheck.start_list_verification
    Start List Verification

destructive

1

Delete, cancel or archive. Ask first, or deny outright.

  • mailercheck.delete_verification_list
    Delete Verification List
03 · HOW IT WORKS

MailerCheck in three steps.

  1. 01Your users connect MailerCheckThey add their MailerCheck api key on Arc0 Connect, under your brand. It goes straight into the vault.
  2. 02You set the rulesReads run, writes like “create Verification List” can wait for the user, and “delete Verification List” can be denied outright.
  3. 03Any agent can actYour agent calls MailerCheck through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
POLICY.TS
await arc0.policies.set('mailercheck', {
  read: 'allow',
  write: 'ask',        // create_verification_list
  destructive: 'deny',  // delete_verification_list
})

# Claude Code: the same connection, one URL
$ claude mcp add --transport http arc0 \
    https://mcp.arc0.ai/u/u_8f2
04 · AUTH AND DATA

How MailerCheck connects.

Users add their MailerCheck api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

The same MailerCheck connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →

AUTH
API key
CREDENTIALS
Per-tenant encrypted vault
MODEL SEES
Results only, never credentials
AUDIT LOG
Every call, on every plan
05 · WORKS WITH

Use MailerCheck from any agent.

Claude
ChatGPT
Cursor
Codex
VS Code
OpenAI Agents SDK
Claude Agent SDK
Vercel AI SDK
Mastra
LangGraph
06 · RELATED

More email apps.

Gmail62 actionsOutlook306 actionsSendGrid364 actionsMixmax94 actionsElastic Email91 actionsResend66 actionsLettr60 actionsPostmark46 actions
ALL EMAIL APPS →
07 · FAQ

MailerCheck and Arc0, answered.

Q01

Can I use MailerCheck with Claude, ChatGPT or Cursor?

Yes. Connect MailerCheck to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the MailerCheck actions you allow.

Q02

How do users connect MailerCheck?

Users add their MailerCheck api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.

Q03

Which MailerCheck actions can my agent take?

9 in total: 6 read, 2 write and 1 destructive, such as “create Verification List”. Your policies decide which of them each agent may call.

Q04

Can I stop my agent from deleting things in MailerCheck?

Yes. Actions like “delete Verification List” are graded destructive. Set destructive actions to deny, or to ask so the user approves each one, and blocked calls still show up on the audit log.

Q05

Can my own backend call MailerCheck too?

Yes. The same MailerCheck connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.

Get started

Plug MailerCheck into your agent.

Your users connect MailerCheck once, under your brand. Your agent gets 9 actions behind your policies, with every call on the record.

Connect MailerCheckBrowse all apps →

Free to build · MCP + REST · Audit log on every plan