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

Beyond the annotations it discloses the key behavioral caveat — computation is local and does not verify bank existence — plus a concrete pricing/cost model ($0.01/call, 25 free, failures free) that explains the idempotentHint=false annotation ('each call is charged, so repeats are not free'). The 'reads or computes only' line echoes readOnlyHint, but the added cost and local-validation context is substantive.

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?

Front-loaded with the purpose and ISO scope, then routing, then caveats, then pricing — logical order with no wasted preamble. It is dense and on the long side, and the pricing clause is verbose relative to its importance, keeping it just short of a 5.

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?

No output schema exists, yet the description effectively previews the response by listing the checks performed (institution code, country name, location, branch, head-office flag, test/passive participant). For a single-parameter validation tool, an agent has everything needed to call it and interpret the result.

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?

With 100% schema coverage and one parameter, the schema already defines 'bic' as an 8- or 11-character code. The description reinforces the 11-character form and supplies a concrete example (bic=DEUTDEFF500) that shows the expected format beyond the schema's terse wording.

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 and resource ('Check a BIC (SWIFT code) against the ISO 9362 structure') and enumerates exactly which components are examined (institution, country, location, branch, head-office, test/passive, 11-char form). It also names a sibling it is not ('for account numbers use validate_iban'), so an agent can route without opening any 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?

Gives both when-to-use ('before an international transfer or to clean payment data') and an explicit alternative with its selection condition ('for account numbers use validate_iban'). The 'checks format and country, not whether the bank exists' line further scopes when this tool is insufficient.

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