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

No annotations are provided, so the description must carry the behavioral burden. It describes the output contents but does not explicitly state that the operation is read-only, has no side effects, or any error conditions. It does not contradict annotations (none exist), but it also does not fully disclose behavior beyond the data returned.

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 sentence with no wasted words, front-loading the main point and then enumerating the response contents. It is concise, though the list of fields is long; still, it remains 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?

With no output schema, the description thoroughly enumerates the expected response fields, giving an agent a clear picture of what data it will receive. For a simple one-parameter tool, this is complete; no additional guidance about pagination or errors seems necessary.

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?

The schema already documents the tld parameter at 100% coverage, including that Unicode and xn-- forms work. The description does not add extra meaning beyond restating that it targets 'one top-level domain', so it meets the baseline for full schema coverage without adding value.

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 retrieves a single top-level domain and enumerates the exact data fields returned (type, registry, RDAP server, root dates, registrar prices, change history). This is specific and distinct from sibling tools like search_tlds (which likely searches) and tld_changes (which likely tracks changes).

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 this is for a single known TLD, but it does not explicitly mention alternatives or when to use search_tlds or tld_changes. It provides clear context but no exclusions, so it stops short of full guidance.

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