Validate BIC/SWIFT code

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

The description explicitly states it checks 'structural' validity, which conveys that it does not verify existence or authenticity. It also provides the exact character layout, adding behavioral detail beyond just 'validates BIC'. However, it does not mention return value format or case sensitivity, which are minor gaps given no annotations.

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, front-loaded sentence that immediately says what the tool does, followed by the structural rule. Every word earns its place, with no filler or repetition.

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?

For a one-parameter validator with no output schema, the description provides sufficient context: the purpose, the accepted format, and implicit return behavior. It is fully complete for the tool's complexity.

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 'bic' parameter with examples, and the description adds the full structural breakdown (4-letter bank, 2-letter country, etc.), giving semantic richness beyond the schema. With 100% schema coverage, this added detail lifts it above the baseline.

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 uses a specific verb 'Checks whether' plus the resource 'BIC/SWIFT code' and clearly defines the valid structure (8 or 11 characters with bank/country/location/branch codes). This distinguishes it from sibling validators like validate_iban and validate_mt_message.

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 clearly indicates the tool's scope (BIC validation) through the title and format explanation, giving clear context for when to use it. It does not explicitly name alternatives or exclusion criteria, but the self-contained nature of the tool makes the intended use obvious.

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