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

No annotations are provided, so the description carries the burden. It does disclose the algorithm (mod-97 checksum) and that the BIC check is a format check rather than an existence check, which is genuinely useful. However it says nothing about the outcome for invalid input, whether it returns a boolean or raises, or whether input normalization (spaces, case) is handled.

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; the required resource comes first and the optional modifier trails. Nothing to trim.

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 annotations and no output schema, the description should say what a result looks like (valid/invalid, checksum failure detail). It covers the validation semantics but leaves the return contract for a nested-object input entirely unstated.

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 0%, so the description must compensate. It does name both fields implicitly (IBAN required, BIC optional) and gives their standards, but adds no format constraints such as country-code length, allowed characters, or whitespace handling for a nested IbanInput object.

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 (validate) plus resource (IBAN) and pins the exact standard: ISO 13616 mod-97 checksum, with an optional ISO 9362 BIC format check. The resource name alone distinguishes it from the sibling validators (validate_isin, validate_ean, validate_luhn), so an agent can select it 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?

Usage is implied by the name and by the family of validate_* siblings, but there is no explicit when-to-use statement, no mention of alternatives (e.g. when to prefer a broader bank-account validator like validate_routing or can_pay), and no stated prerequisites. Adequate but with a clear gap.

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