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

Annotations already declare readOnlyHint=true, and the description adds useful behavioral context: that availability, prices, and renewal details are returned when supplied, and that missing fields stay unconfirmed with a recommendation to verify at the registrar. This goes beyond the annotations and helps set expectations about data reliability.

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?

The description is three concise sentences that front-load the core purpose and provide examples and caveats without unnecessary fluff. It is well-structured and efficient.

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?

Given the tool's moderate complexity, the schema's full coverage, and annotations, the description is largely complete. It explains the returned data, the unconfirmed fields, and the two input modes. It does not explicitly mention the tlds filter, but that is adequately described in the schema.

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% with descriptive parameter texts, and the description adds valuable examples and clarifies the expansion behavior for bare labels and the exact_extension use case. It enhances understanding of the 'name' parameter beyond the schema alone.

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 clearly states the tool's purpose: to request availability and quotes for a name across multiple TLDs at once, with examples for both bare labels and full domains. It distinguishes itself from likely siblings by emphasizing the multi-extension capability, though it doesn't explicitly name the alternatives.

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?

It explains when to use the tool (checking a name across many extensions) and even covers the two input modes (bare label vs full domain) with concrete examples. However, it doesn't mention when NOT to use it or compare it to sibling tools like check_availability or find_domains.

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