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

Annotations already cover read-only, idempotent, non-destructive, and open-world behavior. The description adds genuinely useful context beyond those: rate-limiting, live/real-time response ('right now'), and the tri-state existence outcome (да | нет | не_установлено).

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 lean and front-loaded: the live-registry behavior and status categories appear first, followed by the optional `name` usage. The trailing Russian sentence repeats the registry-live idea, adding minor redundancy without hurting scannability.

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 an output schema present and strong annotations, the description supplies the missing operational details: live behavior, speed, rate limits, status categories, and the role of `name`. It still lacks explicit UNP format and sibling routing, so it is not fully complete.

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 0%, so the description must carry parameter meaning. It usefully explains that `name` is the document-derived value used for a name-match verdict, but it never defines `unp` or its format beyond the registry context and the schema title, leaving a real gap for the required parameter.

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 identifies the tool as a live registry lookup for Belarusian payers and enumerates the returned data (existence status, address, registration date, tax office, bankruptcy cases, etc.). It does not explicitly contrast with sibling tools lookup_company and search_companies, but the 'right now' live-registry framing and concrete fields make the purpose unambiguous.

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 states a clear usage context: pass `name` from your documents to get a name-match verdict, and notes the operation is fast but rate-limited. It does not explicitly say when to use this tool instead of the siblings, so it misses the top score.

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