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

Annotations already mark the tool read-only, idempotent, and non-destructive. The description adds meaningful behavioral detail beyond these: no registry call is made, responses carry provenance and a sha256 hash, and withheld fields are explained with reasons. No contradiction with annotations.

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 front-loaded with the core purpose and information-dense output details. The trailing Russian sentence largely restates the English and adds slight redundancy, but overall the length is appropriate and free of filler.

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 simple one-parameter read-only lookup with an output schema, the description covers the stored nature, result contents, provenance, and speed. Nothing critical is missing for an agent to invoke the tool correctly.

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 defines only the unp parameter with no description, so the 9-digit format stated in the tool description is essential and compensates for 0% schema coverage. It does not discuss validation edge cases, but for a single required parameter this is adequate.

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 returns a collected public card for a Belarusian business entity by 9-digit UNP and enumerates the contained fields. It is specific about the resource and scope, though it stops short of explicitly naming sibling tools to differentiate them.

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 gives clear context: use this when you have a UNP and need a stored public card without making a live registry call. It does not explicitly say when to prefer check_counterparty or search_companies, but the stored/no-registry-call framing makes the intended use case evident.

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