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

Annotations already declare read-only, idempotent, non-destructive, and closed-world behavior. The description adds meaningful behavioral scope by specifying that it checks structure length and country/location/branch components, though it does not explain what happens or what is returned on invalid input.

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?

One front-loaded sentence with no filler. Every clause adds validation scope rather than repeating the title or schema.

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 simple one-parameter validator, annotations and the schema cover invocation safety and input. However, with no output schema, the description does not explain return/error behavior on an invalid BIC, leaving a gap for correct interpretation.

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 single `bic` parameter is fully described in the schema, and the description adds the 8-or-11-character constraint plus the components being parsed, going beyond the schema's example.

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?

Opens with the specific verb 'Validate' and resource 'BIC/SWIFT code', then names the checked components: structure, country, location, and branch code. Sibling validators target other identifiers, so an agent can distinguish this tool 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?

The name and description imply this tool is for BIC/SWIFT validation, but there is no explicit statement of when to choose it over sibling validators or any exclusions/preconditions. Usage is clear enough to infer, but not fully guided.

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