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Check your email domain MCP server

Which MCP servers are Check your email domain's own, from the official registry and from asking its own domain, whether they answer, and what they offer. A program checked each of these, nobody copied them from a product page.

read 2026-10-28

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Whose server it is
  • Registry namecom.dmarcshark/email-dns-checkerverified in the MCP registry

The registry name sits under dmarcshark.com. The registry only lets a publisher use that namespace after proving control of the domain through DNS or HTTP.

When we asked itchecked 2026-10-28
  • Stateanswerschecked 2026-10-28
  • Tools2
  • Server calls itselfdmarc-shark
  • Server version1.0.0
  • Protocol version2025-06-18

On 2026-10-28 the server answered initialize and tools/list without a sign-in. First answer in 472 ms.

Should an agent connect itNot proven either way yet
  • Its tools do every use case we checked: review which services a domain authorizes to send mail; look up the DMARC policy that applies to a domain; inspect MX mail routing and a known DKIM key.
  • Checked on 5 of the 7 days it takes to judge reliability.

Once connected

  • For "review which services a domain authorizes to send mail", the likely first call is check_domain.
  • For "look up the DMARC policy that applies to a domain", the likely first call is check_domain.
  • For "inspect MX mail routing and a known DKIM key", the likely first call is check_domain.
  • Parameters are untyped or undescribed in 2 of 2 tools: check arguments before calling.

Said by rules from the measurements above. The likely first call is a model's pick from the tool list; read its description before relying on it.

Measured dailydaily checks: 5, the first on 2026-10-28
  • INITE MCP scoreafter a weeka score needs 7 daily checks: 5 so far
  • What an agent can do with it3 of 3 use cases
  • Answeredmeasuring5 of the 7 daily checks it takes to print a share
  • Median first answer507 ms
  • Space in an agent's context≈ 192 tokensthe definitions of all its tools (2), which an agent carries on every turn
  • Tool definitionsB · 83 of 100
  • Typed results2 of 2 toolsdeclared outputSchema: results come typed, read once
  • Parameters without a description: in 2 of 2

What an agent can do with it

  • can do · review which services a domain authorizes to send mail
  • can do · look up the DMARC policy that applies to a domain
  • can do · inspect MX mail routing and a known DKIM key

Each of the product's use cases, put to Jev against this server's tool list: can an agent do it with these tools?

Worth a look

None of the five warning signs in these definitions.

A program checks the server once a day: initialize and tools/list, no model. Tokens are the definitions' length at about four characters a token. The grade averages six checks of every tool's name, description, schema and annotations; it says how well the tools are described, not whether they work. The score weighs what was measured and nothing else: answering (25%), doing the product's job (25%), definitions (20%), context (10%), use (10%) and how readily a client connects (10%). A part that was not measured is left out, and a hidden instruction caps the score at 40. The state of vendors' MCP servers: method and numbers →

Tools it offers2 tools · read 2026-10-28
  • check_domain

    Runs fresh, bounded public SPF, DMARC, MX and optionally specified DKIM-selector DNS checks. Changes the public saved snapshot. Rate limited. DNS findings do not prove message authentication.

  • get_saved_result

    Reads the last saved, timestamped public snapshot without making any DNS queries. Results expire after 90 days.

How to connect

Add the server to your MCP client config. Claude Desktop, Cursor and most other clients read this shape:

{
  "mcpServers": {
    "email-dns-checker": {
      "type": "http",
      "url": "https://dmarcshark.com/mcp"
    }
  }
}

Add it

Claude Code, in a terminal

claude mcp add --transport http dmarcshark https://dmarcshark.com/mcp

Add to CursorAdd to VS Code

claude.ai, ChatGPT and other clients: add https://dmarcshark.com/mcp as a custom connector in the settings.

Each line is something a program found when it went looking: the registry entry, the server's own answer, a spec that parses. A missing line means we did not find it, not that it does not exist.