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

With no annotations, the description carries the full disclosure burden. It explains error behavior for a non-existent slug, clarifies the null meaning of first_loan_zero_percent, highlights the regulator registry link as a primary source, and lists the returned data areas. It does not mention permissions or side effects, but it is a read-style endpoint and no mutation is suggested.

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 long but information-dense, and every listed item contributes because there is no output schema to document return values. It is front-loaded with the core purpose, then expands into well-grouped return categories. Slightly run-on, but justified by the complexity.

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?

Given the absence of an output schema, the description does substantial work by enumerating the main result categories, error behavior, null semantics, and source-attribution requirement. It could be more complete with exact field types or value formats, but it is sufficient for an agent to select and 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 already documents the sole parameter slug at 100% coverage, including its format, example, and instruction to derive it from list_mfo, search_offers, or get_category. The description only restates 'по slug' and adds no additional meaning beyond the schema, so the baseline 3 is appropriate.

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 identifies a precise resource and scope: 'Полная карточка одной МФО по slug'. It clearly differentiates this from list/search endpoints and explicitly points to get_reviews for reviews, so the agent knows exactly what this tool does and what it is not.

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 states that reviews should be fetched through get_reviews, which is an explicit alternative. It also implies use when a complete single-MFO card is needed, though it does not explicitly contrast with list_mfo, get_category, or search_offers in the description itself.

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