Mailx Tools

Free Agent Skills from MailX that teach AI agents how to diagnose and fix email deliverability issues using the MailX MCP server.

What's a Skill? A SKILL.md file with workflow instructions an AI agent loads on demand. The format is an open standard adopted by Anthropic (Claude) and OpenAI (Codex CLI, ChatGPT). Learn more at agentskills.io.

Available Skills

email-deliverability

Diagnoses and fixes email deliverability issues by checking SPF, DKIM, DMARC, BIMI records, blacklist status, and SMTP/IMAP server connectivity. Generates DNS records for email authentication.

Activates when the user asks about: email going to spam, domain reputation, DNS authentication setup, mail server configuration, sender verification, or email infrastructure troubleshooting.

Installation

Claude Code (recommended)

/plugin marketplace add Mailwarm/mailx-skills
/plugin install email-deliverability@mailx-skills

That's it. The skill activates automatically when relevant.

Claude.ai

1. Download SKILL.md
2. Go to Claude.ai → Settings → Skills
3. Upload the file and enable it

Claude API

curl -X POST https://api.anthropic.com/v1/skills \
  -H "x-api-key: $ANTHROPIC_API_KEY" \
  -H "anthropic-beta: skills-2025-10-02" \
  -F "display_title=Email Deliverability" \
  -F "files[]=@plugins/email-deliverability/skills/email-deliverability/SKILL.md"

Then reference the returned skill_id when calling the Messages API.

Requirements

The skill requires the MailX MCP server for the actual tool execution. To install the MCP server in Claude Desktop / Cursor / Claude Code:

{
  "mcpServers": {
    "mailx": {
      "type": "http",
      "url": "https://tools.themailx.com/mcp"
    }
  }
}

Full setup guide: tools.themailx.com/mcp/docs

What the agent can do once installed

• Audit a domain's email deliverability — checks SPF, DKIM, DMARC, BIMI, and blacklists in one shot
• Generate DNS records — produces ready-to-paste SPF and DMARC records for any provider
• Diagnose mail server issues — tests SMTP and IMAP connections with credentials
• Look up provider settings — finds SMTP and IMAP configs for Gmail, Outlook, SendGrid, Mailgun, etc.

Repository Structure

mailx-skills/
├── .claude-plugin/
│   └── marketplace.json                              ← Claude Code marketplace catalog
└── plugins/
    └── email-deliverability/
        ├── .claude-plugin/
        │   └── plugin.json                           ← Plugin manifest
        └── skills/
            └── email-deliverability/
                ├── SKILL.md                          ← The skill content
                └── references/
                    └── diagnosis.md                  ← Diagnosis decision tree

Versioning

The current SKILL.md is dynamically generated from the live MailX tool catalog at tools.themailx.com/skills/email-deliverability/SKILL.md. This repo is the static, versioned distribution snapshot used by Claude Code marketplace installs.

License

MIT — see LICENSE

Links

• MailX Tools: tools.themailx.com
• MCP Integration Docs: tools.themailx.com/mcp/docs
• Live SKILL.md: tools.themailx.com/skills/email-deliverability/SKILL.md
• Skill discovery: tools.themailx.com/.well-known/skills.json
• Agent Skills spec: agentskills.io