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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false; the description adds the reason for the closed-world claim ('номера не сверяются с госреестрами') and an important epistemic caveat that this is a hint, not a legal opinion. These are genuine additions beyond structured data, though the response structure itself is not described.

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 action and legal basis, and every clause carries information (what is checked, what counts as a defect, the legal-advice disclaimer). It is composed of one very long run-on Russian sentence followed by two terse English sentences, which is dense but not padded.

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 must convey what comes back, and it does: presence/absence of mandatory warnings, registration number detection and format validity, plus flagged risky formulations. Combined with the 'not legal advice' limit, an agent has enough to call it and interpret results, though the exact result shape is unspecified.

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% so the baseline is 3, but the description goes further: it spells out the four categories that map to the 'kind' enum and distinguishes which mandatory warning applies to supplements versus drugs/devices/services, adding interpretive meaning the raw enum labels do not carry.

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 and resource (checks a product card or ad text) and pins the exact legal basis: articles 24–25 of the advertising law and Government decree No. 821, effective 1 Oct 2026. It also enumerates what is examined — mandatory warnings, registration number presence/format (РЗН, ФСР, ЛП, СГР) and risky phrasing — so it is unmistakable against any sibling utility tool.

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 scope statement ('карточки товара на маркетплейсе или рекламы') plus the kind domain (БАД, лекарства, медизделия, медуслуги) makes the applicable context clear, and the deadline note tells the agent when the card-checking regime applies. No explicit exclusions or named alternatives are given, but no sibling tool is a plausible substitute.

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