list_promo_codesCurrently active registrar promo/coupon codes, biggest discount first.
| Name | Required | Description | Default |
|---|---|---|---|
| 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, destructiveHint=false, and openWorldHint, so the safety profile is covered. The description meaningfully adds that results are filtered to currently-active codes and sorted by discount descending, which affects how the agent interprets the output; it omits pagination/rate-limit behavior, which is a modest gap.
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 front-loaded sentence with no filler. The scope constraint and sort order are stated immediately with zero wasted words.
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 read-only list tool with rich annotations, nothing critical is missing about how to call it. However, there is no output schema, and the description never hints at what a returned promo code contains (discount amount, registrar, expiry), leaving the agent unable to anticipate the response shape.
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 50%: api_key is documented in the schema itself, and limit is fully specified structurally (default 25, min 1, max 100). The description adds nothing about either parameter, so the schema carries the load and the baseline 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?
States a specific verb+resource (list promo/coupon codes) plus scope ('currently active registrar') and ordering ('biggest discount first'). It is clearly distinct from the sibling tools, which all deal with domains, TLD pricing, or registrars, though it never explicitly names a distinguishing 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?
No when-to-use or when-not-to-use guidance is given, and no alternative tool is referenced. An agent must infer that this is a discovery aid rather than, say, a pricing lookup, which get_tld_prices and find_cheapest_tlds already cover.
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.