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

There are no annotations, so the description carries the full burden of behavioral transparency. It discloses that the validation uses a 'real national checksum' and parses person/entity structure, which goes beyond basic format checking, but it does not specify output format or error behavior for invalid inputs.

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 a single sentence that starts with the action and includes key details about checksum validation, structure parsing, and that the service is free. No unnecessary words.

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?

With no output schema, the description only partially covers the return structure by mentioning parsed fields (birth date/sex, registration) but does not explicitly state how results are returned or handled for invalid inputs. Given the simple one-parameter nature, it is adequate but not fully complete.

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 provides no description for the 'iin' parameter (0% coverage), so the description compensates by clarifying that it represents a Kazakhstan IIN/BIN and explaining the parsing behavior. This adds meaningful context beyond the raw string type.

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 validates a Kazakhstan IIN/BIN with a real national checksum and parses its structure, distinguishing it from sibling validate_kz_iban which handles IBAN. The verb 'validate' and resource 'Kazakhstan IIN/BIN' are specific and unambiguous.

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 implies usage for anyone needing to validate Kazakhstan IIN/BIN numbers, and the distinction from other validation tools in the sibling list (e.g., validate_kz_iban) provides implicit context. It does not explicitly state when not to use it, but the scope is clear enough.

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