find_cheapest_tldsList domain extensions (TLDs) with the cheapest registrar for first-year registration, renewal, transfer and 3-year total. Prices in USD/year.
| Name | Required | Description | Default |
|---|---|---|---|
| q | No | Only TLDs containing this text, e.g. "ai" | |
| sort | No | popularity | |
| type | No | gtld or cctld | |
| limit | No | ||
| api_key | No | Your TLDers API key. Only needed if your client cannot send an Authorization header or use a ?key= URL. |
Changes observed during successful MCP inspections.
Input schema / properties / api_keyAdded value: +{
+ "description": "Your TLDers API key. Only needed if your client cannot send an Authorization header or use a ?key= URL.",
+ "type": "string"
+}Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is fully covered. The description adds useful format context ('Prices in USD/year') and clarifies what each row represents, but says nothing about rate limits, auth requirements, or result ordering 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?
A single compact sentence that front-loads the resource and enumerates the price dimensions covered, with the unit stated last. No filler, though the dense enumeration of four price types is slightly hard to parse at a glance.
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 no output schema, the description does describe the returned data (cheapest registrar per price dimension in USD/year), which is helpful. However, it omits guidance on when to prefer this over sibling tools and gives no pagination or default-ordering context for a 5-parameter tool.
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 60%: q, type and api_key are documented in the schema, while sort and limit are not. The description adds no parameter-level meaning (no mention of filtering, sorting, or limits), only the price unit, which is relevant to price sorting. Baseline 3 is appropriate since the schema carries most of the load.
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 verb (List) and resource (domain extensions/TLDs) and defines the scope precisely: cheapest registrar for first-year, renewal, transfer and 3-year totals. It is clearly distinct in intent from availability checking, but it does not explicitly differentiate itself from close siblings like get_tld_prices or compare_tlds.
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 mention of alternatives such as get_tld_prices or compare_tlds. The agent must infer from the name alone when this tool is the right choice among six siblings.
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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