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

Annotations already establish readOnly/idempotent/closed-world, so the safety profile is covered. The description adds genuine behavior not in the annotations: the validation is offline and instant, and it flags when the supplied identifiers look like they belong to different persons/entities. It stops short of describing partial-input behavior or the exact response shape.

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?

Front-loaded with the core action and the identifier list, then the payoff (catching typos) and the key property (offline, instant). It is slightly redundant because the same content is given twice in Russian and English, but each version is tight and waste-free.

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 7-parameter, all-optional, no-output-schema tool, the description covers purpose, the identifier set, and even one aspect of the result (mismatched-persons warning). The remaining gap is that it never clarifies that zero required parameters means partial sets are acceptable and what is reported per field.

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 each parameter already carries its own Russian description with digit counts, so the description's digit hints largely duplicate the schema. No additional semantics (e.g. which combinations are meaningful, or behavior when only some fields are supplied) are added beyond what the schema states.

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?

States a specific verb (проверяет/validates) and an explicit, enumerated resource set (ИНН, КПП, ОГРН/ОГРНИП, БИК, расчётный/корреспондентский счёт, СНИЛС), including the checksum method. Nothing among the siblings (amount_in_words, decline_name, working_days) overlaps, so the agent can select this unambiguously.

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?

Gives a clear use context — catching typos before issuing an invoice or payment ("до выставления счёта или платежа") — which tells the agent when to reach for it. It does not name any alternative tool or state exclusions, but no sibling competes for this job.

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