DNS records for a domain.
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": "dns"
}
}| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain name |
Changes observed during successful MCP inspections.
Input schema / properties / domainAdded value: +{
+ "description": "Domain name",
+ "type": "string"
+}Input schema / requiredAdded value: +[
+ "domain"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden, yet it never states that this is a read-only lookup, which record types (A, AAAA, MX, TXT, NS) are returned, or what happens for a nonexistent domain. The only signal beyond the name is that results are scoped to a domain.
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?
At five words it is certainly concise, but it is a sentence fragment rather than a front-loaded statement of purpose. Brevity here reflects under-specification rather than efficiency.
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?
The tool is simple (one parameter), but with no annotations and no output schema the description must explain the return shape and read-only nature, and it does neither. An agent cannot tell what data it will get back or how failures are surfaced.
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 description coverage is 100% with a single required 'domain' string, so the schema already documents the parameter. The phrase 'for a domain' merely restates it and adds no format detail (e.g. whether a subdomain or trailing dot is accepted), so the baseline of 3 applies.
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 'DNS records for a domain' identifies the resource and its scope but supplies no verb, so an agent must infer that it performs a lookup. It also fails to distinguish this tool from the sibling 'dns_lookup', which appears to do the same thing, leaving selection ambiguous.
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?
There is no when-to-use guidance, no prerequisites, and no exclusions. The presence of a near-identical sibling ('dns_lookup') makes the omission more costly, since nothing tells the agent which of the two to pick.
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.