scan.mx Email Diagnostics

Check blacklists

check_blacklist

Read-only

Check whether the domain and its mail server IPs are listed on the Spamhaus (ZEN, DBL, ZRD, AuthBL), SpamCop, GBUdb and PSBL blocklists.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "domain": "<domain>"
    },
    "name": "check_blacklist"
  }
}

Input Schema

Name	Required	Description	Default
`domain`	Yes	The domain to check, e.g. example.com. No scheme or path.

Output Schema

Name	Required	Description	Default
`grade`	No
`score`	No
`checks`	No
`domain`	Yes
`provider`	No
`sections`	No
`selector`	No
`permalink`	No
`smtp_note`	No
`created_at`	No
`expires_at`	No
`updated_at`	No
`smtp_status`	No
`poll_after_seconds`	No

Schema Changelog

Changes observed during successful MCP inspections.

First observedJul 9, 2026

TDQS

A4.2/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already mark readOnlyHint and openWorldHint. Description adds behavioral details: enumerates specific blocklists and clarifies it checks both the domain and its mail server IPs. No contradictions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Single sentence immediately conveys core purpose and lists all addressed blocklists. No redundant words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given an output schema exists, description covers what the tool does and which blocklists. It could optionally mention how results are returned, but likely sufficient.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% with a clear domain description. The description adds context by linking the parameter to the tool's function (check domain and its mail server IPs on specific lists), adding value beyond schema.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool checks domain and mail server IPs against specific blocklists (Spamhaus, SpamCop, GBUdb, PSBL). It distinguishes from sibling tools that check other DNS records (DKIM, DMARC, etc.).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No explicit when-to-use or when-not-to-use guidance is given. The differentiation from siblings is implicit based on the domain check context but lacks direct recommendations.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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