ARC-Relay MCP server

• Registry namecom.arc-relay/mcpverified in the MCP registry

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

• Stateanswerschecked 2026-10-24
• Tools6
• Server calls itselfarc-relay
• Server version1.3.0
• Protocol version2025-03-26

On 2026-10-24 the server answered initialize and tools/list without a sign-in. First answer in 146 ms.

• Its tools do none of the product's use cases we checked: Forward a custom domain's mail to an existing inbox; Send replies from your own domain address; Create separate aliases like hello or work for each purpose.
• Checked on 4 of the 7 days it takes to judge reliability.

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.

• INITE MCP scoreafter a weeka score needs 7 daily checks: 4 so far
• What an agent can do with it0 of 3 use cases
• Answeredmeasuring4 of the 7 daily checks it takes to print a share
• Median first answer392 ms
• Space in an agent's context≈ 435 tokensthe definitions of all its tools (6), which an agent carries on every turn
• Tool definitionsA · 100 of 100
• Typed results0 of 6 toolsdeclared outputSchema: results come typed, read once

• Every tool passes all six checks.

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 →

• check_dmarc

  Check a domain's DMARC, SPF, and MX records. Use this to diagnose email authentication issues.

• check_email_health

  Get a 0-100 email health score for any domain. Checks DMARC, SPF, MX, and DKIM records and returns a letter grade (A+ to F) with actionable recommendations. Use this to audit any domain's email security posture.

• check_health

  Check ARC-Relay service health and uptime.

• check_spf

  Validate a domain's SPF record. Shows mechanisms, DNS lookup count, and warns if over the 10-lookup limit.

• network_leaderboard

  View top relay nodes ranked by reputation score. Filter by region.

• network_stats

  Get public relay network statistics — total nodes, active nodes, messages routed, delivery rate, and the average DMARC rate nodes report about themselves (rates are null until there is traffic).