Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and non-destructive, so the safety profile is covered. The description adds genuinely new context: results include availability plus prices denominated in NOK per year including 25% VAT and a buy_url, which tells the agent the pricing unit, tax treatment and currency of the output.

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: the action and scope come first, then the return payload. The parenthetical example and TLD list are compact and earn their place; nothing is padding.

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?

There is no output schema, and the description compensates by describing the return shape (availability, price with currency/VAT, buy_url). With only two simple parameters and annotations covering safety, almost everything an agent needs is present; only explicit sibling routing is absent.

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%, so 'name' and 'limit' (default 10, max 25) are already fully documented by the schema. The description repeats the mycompany example but adds no syntax, format, or default semantics beyond what the schema provides; 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?

States a specific verb (check) and resource (one name across popular extensions) and enumerates example TLDs, so the operation is unmistakable. It does not name or contrast with the sibling check_domain (which presumably checks a single full domain), leaving the boundary between the two to inference.

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?

The phrase 'check one name ... across the most popular extensions' implies the natural use case (broad availability sweep for a brand/company name), but there is no explicit when-to-use, when-not-to-use, or routing to check_domain/list_extensions. Usage is implied rather than stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.