IP lookup over RDAP plus reverse DNS: network, CIDR, country, org, abuse contact, ASN.
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": {
"ip": "<ip>"
},
"name": "ip_lookup"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| ip | Yes | IPv4 or IPv6 address, e.g. 8.8.8.8 |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the disclosure burden and does add useful context: two upstream sources (RDAP and reverse DNS) and the concrete data categories returned. It omits rate limits, auth requirements, behavior on private/reserved IPs, partial-failure handling when RDAP or rDNS is unavailable, and latency considerations.
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?
One sentence, front-loaded with the action and sources, followed by the returned fields — nothing redundant. It is elliptical (a fragment rather than a sentence), but every clause 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 one-parameter read-only lookup with no output schema, the description does the key work of enumerating return fields so the agent knows what comes back. Remaining gaps are edge-case behavior (private IPs, source failures) rather than core invocation facts.
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?
Schema coverage is 100% with a single documented parameter ('IPv4 or IPv6 address, e.g. 8.8.8.8'), so the schema already establishes format and example. The description adds only that the input is an IP via the tool name, no extra syntax, CIDR acceptance, or validation rules beyond the schema.
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?
States a specific verb+resource ('IP lookup') and names the data sources (RDAP plus reverse DNS) plus the fields returned (network, CIDR, country, org, abuse contact, ASN). This implicitly separates it from geo-only siblings like ip_geo or geolocate_ip, but it never names or contrasts those siblings.
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?
Usage is only implied by the listed output fields; there is no explicit when-to-use, when-not, or routing among the many overlapping siblings (ip, ip_geo, geolocate_ip, whois_lookup, dns_lookup, cidr_calc, ipv4_validate). An agent must infer the boundary from the field list alone.
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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