usom-mcp

Check Domain

check_domain

Read-only

Determine if a domain appears on USOM's malicious-link list, including parent domain matches. Optionally enrich results with VirusTotal.

Instructions

Check whether a domain is listed by USOM, including when a parent domain is listed.

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_domain"
  }
}

Input Schema

Name	Required	Description	Default
`domain`	Yes	Domain such as login.example.com (IDN ok).
`enrich`	No	Also query VirusTotal (needs VIRUSTOTAL_API_KEY).

Output Schema

Name	Required	Description	Default
`kind`	Yes
`note`	No
`cache`	Yes
`error`	No
`input`	Yes
`stale`	Yes	True when a refresh failed and cached data may be outdated; warn the user.
`source`	No		T.C. Siber Güvenlik Başkanlığı / USOM (siberguvenlik.gov.tr)
`matches`	No
`verdict`	Yes
`warnings`	No
`enrichment`	No
`normalized`	No
`data_origin`	Yes
`enrichment_errors`	No
`timestamps_timezone`	No		unspecified

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Oct 6, 2026

TDQS

A3.6/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds a genuinely non-obvious behavioral trait: a domain is reported as listed even if only a parent domain is on the list. It does not mention rate limits or the VirusTotal enrichment path whenever enrich is used.

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?

A single efficient sentence with the primary behavior front-loaded and the parent-domain caveat trailing as a qualifier. No filler or redundancy.

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?

An output schema exists, so return values need not be explained. The description conveys what is checked and the parent-domain nuance, which covers the core behavior. It leaves the choice among sibling check tools unaddressed, a minor gap.

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

Parameters3/5

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

Schema description coverage is 100%, so both parameters (domain including IDN, enrich with its API-key requirement) are fully documented in the schema. The description adds nothing about parameters, which is acceptable given full schema coverage and yields the baseline score.

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

Purpose4/5

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

States a specific verb and resource: check whether a domain is listed by USOM. The mention of parent-domain listing further sharpens scope. It does not explicitly contrast itself with siblings check_url or check_ip, but the domain-specific framing makes the resource clear.

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

Usage Guidelines2/5

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

No statement of when to use this tool versus check_url, check_ip, or watch_check. There are no prerequisites or exclusions mentioned. The agent must infer usage purely from the name and resource type.

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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