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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so the safety profile is fully covered. The description adds only that the source is the Минюст foreign-agents register, which is useful context but discloses nothing beyond that (no result semantics, no rate/coverage caveats). With annotations carrying the behavioral load, a 3 is appropriate.

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 front-loaded sentence with zero filler that conveys verb, resource, register and input method. Every word earns its place.

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 one-parameter read-only lookup with full schema coverage and clear annotations, the definition is essentially sufficient, and no output schema means return values need not be explained. It only lacks an explicit pointer to check_inoagent_person for the person-register counterpart.

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 100% and the single parameter is documented with type, a 10-digit pattern, and a Russian description; the description merely restates 'по ИНН'. Baseline 3 applies since the schema does the heavy lifting and the description adds no format or syntax detail beyond it.

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 (проверка), resource (организация) and the exact register (реестр иностранных агентов Минюста РФ), plus the key input (по ИНН). An agent can immediately distinguish it from the individual-lookup sibling check_inoagent_person without opening the schema.

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 scoping phrase 'по ИНН' and 'организация' implies this is the register lookup for organizations, which is adequate for a simple lookup tool. However, there is no explicit when-to-use guidance and no mention of the natural alternative, check_inoagent_person, for individuals, so routing is left to inference.

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