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

With no annotations present, the description carries the full behavioral burden and meets it: it discloses the exact return shape (mfo_slug, canonical_url, total, reviews ordered new-to-old with author/rating/date/text), and guards against misinterpretation for both edge cases — empty reviews means total=0 and 'это не низкая оценка', and a nonexistent slug yields isError with 'Не найдено'. The read-only nature is conveyed through 'Возвращает' and the edge-case handling.

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 longer than minimal, but every sentence earns its place: scope, return format, two edge-case clarifications, and usage routing to get_mfo. The core purpose is front-loaded in the first clause. It is appropriately sized for a tool with no output schema, though the middle field enumeration is dense and could be slightly more compact.

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?

Since there is no output schema, the description must explain return values, and it does so comprehensively: all fields, ordering, and both edge cases are covered. It also includes sibling routing and notes where the slug should come from. For a 2-parameter read tool, nothing essential an agent needs to call it correctly is missing.

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%, so the baseline is 3. The description reinforces the slug parameter's role ('по slug') and the new-to-old ordering that affects limit, but it does not add syntax or format details beyond what the schema already documents for either slug or limit. The schema does the heavy lifting here.

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 opens with a specific verb+resource: 'Последние отзывы заёмщиков об одной МФО по slug' — fetching recent borrower reviews for a single MFO identified by slug, and further narrows scope to public, site-published reviews only. It explicitly differentiates from get_mfo by stating that summary rating and terms belong to that sibling, so an agent can disambiguate 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?

Provides explicit when-to-use guidance: 'Используйте для вопросов о репутации и опыте клиентов' (use for reputation and client-experience questions). It also gives a clear exclusion by routing 'сводный рейтинг и условия — get_mfo' (summary rating and conditions → get_mfo), naming the specific alternative and the condition that selects it.

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