Domain age and registrar intel via RDAP: registration date, age in days/years, expiry, last changed, registrar name. [PAID: $0.015 USDC per call via x402]
| Name | Required | Description | Default |
|---|---|---|---|
| domain | Yes | Domain to check (e.g. example.com) |
Changes observed during successful MCP inspections.
Input schema / additionalPropertiesPrevious value: -trueNew value: +falseInput schema / properties / domainAdded value: +{
+ "description": "Domain to check (e.g. example.com)",
+ "type": "string"
+}Input schema / properties / promptRemoved value: -{
- "description": "Input prompt for this service.",
- "type": "string"
-}Input schema / requiredPrevious value: -[
- "prompt"
-]New value: +[
+ "domain"
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations present, the description carries the burden and does disclose two genuinely useful behavioral traits beyond structured data: the data source (RDAP) and the cost model ($0.015 USDC per call via x402), which an agent must know before invoking. It does not state read-only semantics, failure modes for unsupported TLDs, or rate limits, so it falls short of full transparency.
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?
A single sentence front-loads the resource and protocol, then lists outputs, with pricing appended in a clearly marked bracket. No filler.
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 lookup with no output schema and no annotations, listing the returned fields and the payment requirement covers most of what an agent needs. Gaps are minor: no mention of failure behavior or whether the call is strictly read-only.
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% for the single 'domain' parameter, so the schema already supplies the format example (example.com). The description adds nothing about the parameter itself, making the baseline 3 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 states a specific resource (domain age/registrar intel), names the protocol (RDAP), and enumerates the exact fields returned (registration date, age, expiry, last changed, registrar). This is far more precise than a tautology, though it never names the closest sibling (liminal-dns-lookup) to draw an explicit boundary.
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: an agent can infer this is for checking domain registration history, but there is no explicit when-to-use, no when-not-to-use, and no routing to alternatives such as the DNS lookup or HTTP headers tools. Adequate but leaves selection to inference.
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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