mailx-tools
Mailx Tools is an MCP server that gives AI agents a complete email-deliverability diagnostics toolkit.
What it can do
- Spf Check: Check if a domain has a valid SPF (Sender Policy Framework) DNS record. SPF specifies which mail servers are authorized to send email on behalf of a domain.
- Dkim Check: Check if a domain has a valid DKIM (DomainKeys Identified Mail) DNS record for a given selector. DKIM allows the receiver to verify that an email was sent by the domain owner.
- Dmarc Check: Check if a domain has a valid DMARC (Domain-based Message Authentication, Reporting & Conformance) DNS record. DMARC tells receiving servers what to do with emails that fail SPF or DKIM c
What data it sees
Do you need an account
No: the server works without sign-in
Mailx Tools is an MCP server that gives AI agents a complete email-deliverability diagnostics toolkit. Verify your domain's ▎ SPF, DKIM, DMARC, and BIMI configuration, look up any DNS record type (MX, CNAME, TXT, PTR), check blacklists, test SMTP and ▎ IMAP servers, and auto-generate SPF and DMARC policies. Designed for marketers, deliverability engineers, and anyone ▎ troubleshooting why emails aren't landing in the inbox.
How to connect
How to connect mailx-tools to Claude
The server address to paste into Claude settings:
https://mailx-tools--mailwarm.run.tools
- Open Claude (claude.ai or the desktop app).
- Go to Settings → Connectors.
- Click Add custom connector.
- Paste the server address copied below into Remote MCP server URL and click Add.
- In a chat, click + → Connectors and switch the new connector on.
Custom connectors are available on Free, Pro, Max, Team and Enterprise plans (Free is limited to one). On Team and Enterprise an organization Owner adds the connector first under Organization settings → Connectors.
Authorization
After you click Add, a sign-in window for the service opens. Sign in with your own account and approve access. Claude never sees your password.
How to connect mailx-tools to ChatGPT
The server address to paste into ChatGPT settings:
https://mailx-tools--mailwarm.run.tools
- Open ChatGPT in a browser (chatgpt.com). A Plus, Pro, Business, Enterprise or Edu plan is required.
- Turn on developer mode once: Settings → Apps → Advanced settings → Developer mode.
- Open Settings → Connectors and click Create.
- Fill in the form: Name (anything), Description (one line about what the service does), MCP server URL (copy it below).
- Under Authentication choose OAuth if the service requires sign-in, otherwise None. Click Create.
- In a new chat open + → Apps/Connectors and enable the connector.
OpenAI has renamed this section before (Connectors → Apps/Plugins). If the label differs, search settings for "developer mode". On Business/Enterprise workspaces an admin must allow custom connectors first.
Authorization
On first use ChatGPT opens the service's sign-in window. Sign in and approve access.
How to connect mailx-tools to Cursor
The server address to paste into Cursor settings:
https://mailx-tools--mailwarm.run.tools
Fastest: click Open in Cursor below and confirm the prompt.
Manually:
- In Cursor open Settings → Cursor Settings → MCP and click Add new global MCP server.
- Paste the JSON copied below into
~/.cursor/mcp.json(per project:.cursor/mcp.jsonin the repo root). - Save the file. The server appears in the MCP list; authorize it there if asked.
Authorization
If the service needs sign-in, an authorize button appears next to the server in the MCP list.
Server tool list (16)
Raw names from tools/list. Only developers need these.
| spf_check | Check if a domain has a valid SPF (Sender Policy Framework) DNS record. SPF specifies which mail servers are authorized to send email on behalf of a domain. |
| dkim_check | Check if a domain has a valid DKIM (DomainKeys Identified Mail) DNS record for a given selector. DKIM allows the receiver to verify that an email was sent by the domain owner. |
| dmarc_check | Check if a domain has a valid DMARC (Domain-based Message Authentication, Reporting & Conformance) DNS record. DMARC tells receiving servers what to do with emails that fail SPF or DKIM checks. |
| bimi_check | Check if a domain has a valid BIMI (Brand Indicators for Message Identification) DNS record. BIMI allows brands to display their logo next to authenticated emails in supporting email clients. |
| dmarc_generate | Generate a DMARC DNS record for a domain. Returns the record name, value, and type ready to be added to DNS. |
| spf_generate | Generate an SPF DNS record for a domain based on the email provider being used. Returns the record name, value, and type ready to be added to DNS. |
| smtp_check | Test an SMTP server connection by attempting to connect and authenticate. Optionally sends a test email to verify full sending capability. |
| imap_check | Test an IMAP server connection by attempting to connect and authenticate. Use this to verify email receiving configuration. |
| smtp_finder | Look up SMTP server settings (host, port, encryption) for a given email provider. Use this to find the correct SMTP configuration for services like Gmail, Outlook, SendGrid, etc. |
| imap_finder | Look up IMAP server settings (host, port, encryption) for a given email provider. Use this to find the correct IMAP configuration for services like Gmail, Outlook, Yahoo, etc. |
| blacklist_check | Check if a domain or IP address is listed in popular email blacklists (DNSBLs). Being blacklisted can severely impact email deliverability. |
| mx_lookup | Look up MX (Mail Exchanger) records for a domain. Returns the mail servers and their priorities. |
| txt_lookup | Look up all TXT records for a domain. TXT records contain SPF policies, domain verification tokens, DKIM keys, and other metadata. |
| cname_lookup | Look up CNAME (Canonical Name) records for a domain. Shows where a hostname aliases to. |
| ptr_lookup | Reverse DNS lookup. Find the hostname associated with an IP address. A valid PTR record is important for email sending reputation. |
| dns_lookup | Look up all DNS records for a domain in one query. Returns A, AAAA, CNAME, MX, NS, TXT, and SOA records. |