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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds useful behavior beyond that: each call returns availability plus the best 2-year price, and it names the default TLD set. It provides no unnecessary side-effect claims.

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?

Three short sentences front-load the core behavior and then give defaults and constraints. It is compact, though the defaults and max-8 detail also appear in the schema.

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 simple read-only lookup with two parameters, the description and schema together cover what an agent needs: required name, optional tlds, defaults, and return concept. It could be slightly more explicit about the return shape or about using list_supported_tlds to know valid TLDs.

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 coverage is 100%, so the baseline applies; both parameters are documented in the schema, including the tlds default. The description reinforces defaults and the 8-TLD maximum, but does not add new parameter-level meaning beyond the schema.

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 a specific action and object ('Check one name ... across several TLDs at once') and states the result (availability plus best 2-year price). It is clear and self-contained, but it does not explicitly contrast with sibling tools like check_domain or compare_tld_prices.

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 description implies the primary use case—checking a single name over the default TLD set—and gives constraints (max 8 TLDs). It does not state when to prefer an alternative or mention that check_domain/compare_tld_prices exist for single-domain or price-comparison needs.

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