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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. Beyond that, the description discloses the shape of the response (id, provider, account, quota), which is genuinely useful because no output schema exists; it does not mention empty-list behaviour or auth requirements, which keeps it short of a 5.

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?

A single sentence, front-loaded with the verb and resource, then the returned fields. Every clause carries information the agent needs; nothing is redundant.

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 trivial zero-param list tool with no output schema, listing the returned fields plus the cross-tool id dependency covers what an agent needs to call it and use the result. Minor omissions (empty list, no-pagination confirmation) prevent a 5, and the Russian-language text may read inconsistently against English sibling definitions.

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 tool takes zero parameters and the schema is empty, so the baseline is 4. The description correctly implies no input is needed, adding nothing misleading about arguments.

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 names a specific verb and resource ('Список подключённых облачных хранилищ пользователя') and enumerates the returned fields (id, provider, account, quota). It implicitly separates itself from siblings by noting the id is required by all other tools, though it never names an alternative explicitly.

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 parenthetical 'id (нужен всем остальным инструментам)' tells the agent this is the entry-point call whose output feeds every sibling, which is strong usage context. There are no explicit when-not conditions, but for a zero-parameter discovery tool the selection logic is effectively unambiguous.

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