Resolve a hostname to its IPv4 addresses and look up each one's ASN, network prefix, country code, and network owner via Team Cymru's DNS-based WHOIS service (no API key). Country-level only — not city/street geolocation.
| Name | Required | Description | Default |
|---|---|---|---|
| host | Yes | Hostname or bare IPv4 address to look up |
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden of behavioral disclosure. It usefully adds the data source (Team Cymru), the DNS-based mechanism, and the no-API-key requirement. It does not mention failure behavior, rate limits, or that this is a read-only operation, but for a simple lookup tool the disclosed behavior is reasonably adequate.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Two sentences with no filler. The first sentence front-loads the main purpose and data returned, and the second sentence adds a crucial scope limitation and the no-API-key detail. Every word earns its place.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a single-parameter lookup tool, the description covers the input type, the resolution behavior, the returned data fields, the service used, and the country-level limitation. No output schema exists, but the enumerated return fields give the agent enough context. Minor gaps like explicit failure handling or output formatting do not materially impair correct invocation.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
The input schema already fully describes the single 'host' parameter as 'Hostname or bare IPv4 address to look up' (100% coverage). The description restates this concept and adds that the hostname is resolved to IPv4 addresses, but it does not add meaningful new parameter semantics beyond the schema. Baseline 3 is appropriate.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
The description names a specific action ('Resolve a hostname to its IPv4 addresses'), the data source (Team Cymru's DNS-based WHOIS), and the exact fields returned (ASN, network prefix, country code, network owner). It also distinguishes itself from generic geolocation by stating 'Country-level only', which separates it from any city/street lookup tool.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
The description clearly implies when this tool is appropriate: for hostname-to-IP-ASN/country lookups. It gives an explicit exclusion ('not city/street geolocation') and notes the no-API-key advantage. It does not name a specific sibling alternative, but the sibling list contains no other geolocation tool, so the context is clear.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.
Many tools audit overlapping site signals (seo_audit vs structured_data_extract vs tech_stack_fingerprint; page_performance_check vs pagespeed_insights; ssl_cert_check vs ssl_labs_grade; broken_link_check vs sitemap_url_validator), so an agent could initially pick the wrong one. Descriptions usually clarify the distinction, but the boundaries are not always obvious.
Most names follow a snake_case target+operation pattern (ssl_cert_check, email_deliverability_check), but check_open_ports and check_robots_sitemap reverse the order, and the action suffixes vary widely (check, audit, validate, lookup, extract, grade, report, insights). Still readable, but not a single predictable convention.
At 29 tools, the server is above the 25-tool threshold and feels like an undifferentiated grab bag of single-purpose audits rather than a tightly scoped toolkit. Many checks could be consolidated (e.g. the separate SSL and performance tools, or domain_report versus its component checks).
For a web/domain/email/security diagnostics toolbelt, the coverage is unusually broad: DNS, TLS, email, SEO, structured data, vulnerabilities, ports, redirects, and more are all represented. Minor gaps exist (no generic HTTP request/debug tool, no zone-transfer or full WHOIS history), but agents can accomplish most diagnostic workflows without hitting dead ends.