tools_domain_age_checkerFree public API. Returns a domain's registration date, age in days + years, last-updated date, and expiration.
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to check. |
| Name | Required | Description | Default |
|---|---|---|---|
| ok | Yes | Always true here; failures return an isError result instead. | |
| data | Yes |
Changes observed during successful MCP inspections.
Output schema / (root)Previous value: -nullNew value: +{
+ "$schema": "http://json-schema.org/draft-07/schema#",
+ "additionalProperties": true,
+ "description": "Registration date and age of the domain.",
+ "properties": {
+ "data": {
+ "additionalProperties": true,
+ "properties": {
+ "ageDays": {
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "ageYears": {
+ "type": [
+ "number",
+ "null"
+ ]
+ },
+ "created": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "domain": {
+ "type": "string"
+ },
+ "expires": {
+ "type": [
+ "string",
+ "null"
+ ]
+ },
+ "updated": {
+ "type": [
+ "string",
+ "null"
+ ]
+ }
+ },
+ "required": [
+ "domain",
+ "ageDays",
+ "ageYears"
+ ],
+ "type": "object"
+ },
+ "ok": {
+ "description": "Always true here; failures return an isError result instead.",
+ "type": "boolean"
+ }
+ },
+ "required": [
+ "ok",
+ "data"
+ ],
+ "type": "object"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. The description adds 'Free public API,' which implies no cost and likely no authentication, but omits rate limits, auth specifics, and error behavior.
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 short sentences, front-loaded with the free/public nature and then the returned data. No filler or repetition beyond the brief return list.
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?
With rich annotations, a full output schema, and a single well-described parameter, the description is nearly sufficient for invocation. It still leaves a gap in selection guidance against whois_lookup, but the core operational picture is clear.
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% and the single domain parameter is documented there as 'Domain to check.' The description does not add syntax or format details beyond the schema, so 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 the resource (a domain) and the specific outputs (registration date, age in days/years, last-updated date, expiration), so the agent knows exactly what this tool returns. It does not, however, explicitly differentiate from the sibling whois_lookup, which likely overlaps on registration data.
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?
No when-to-use guidance, prerequisites, or alternatives are given. It does not say to prefer this over whois_lookup for age checks or when it is inappropriate.
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.