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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety needs no repeating. The description does add value beyond them by disclosing the return shape (a document with a link) despite no output schema, but it says nothing about behavior for nonexistent/invalid domains or about cost/latency of the open-world call.

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?

One short clause, front-loaded with the resource and the output form; there is no filler whatsoever.

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 single-parameter read with full annotation coverage and no output schema, the description gives the essential missing piece — that the result is a citable document with a link. Only the boundary with whois_domain/site_facts and error behavior are 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 coverage is 100% and the single parameter 'id' is documented as 'домен', so the schema does the work. The description does not clarify the expected domain format (with/without scheme or subdomain), so it adds nothing beyond the schema — baseline 3.

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 says it returns one domain in detail as a document with a link, which conveys the resource and output shape, but the verb is implied rather than stated (the name 'fetch' is generic) and it never distinguishes itself from close siblings like whois_domain, check_domain or site_facts.

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?

'для цитирования в ответе' hints at the usage context — use it when you need a citable detail card — but there is no explicit when-not guidance and no named alternative for the narrower lookups the sibling tools cover.

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