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

The description adds meaningful behavioral context beyond the annotations: it clarifies the check is structural (ISO 9362 format and country code), not a live network or bank existence verification, and states that it 'Returns signed XDR-1 receipt,' informing the agent about the output artifact. No contradiction with the readOnlyHint or idempotentHint 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 three sentences with no wasted words. It front-loads the primary action and validation criteria, then adds usage context, and finally states the return behavior. Every sentence earns its place.

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 single-parameter validator with strong annotations and an output schema, the description is fully sufficient: it explains what the tool does, when to use it, what it validates, and what it returns. There are no significant gaps an agent would need to fill.

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 input schema already fully describes the only parameter 'bic' with details about length and allowed characters, so the description adds little new semantics. The mention of ISO 9362 structure is helpful but does not significantly enhance the parameter's meaning beyond what the schema provides, matching the baseline for high schema coverage.

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 states a specific verb ('Validate'), a specific resource ('SWIFT/BIC code'), and the exact standard used ('ISO 9362 structure'), listing the relevant components: bank code, ISO country, location, optional branch. This clearly differentiates it from sibling validation tools like iban_check or ifsc_check, even without naming them.

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 gives explicit usage context: 'Run before foreign wire transfer dispatch to prevent routing rejection.' This tells an agent when to invoke the tool, though it does not explicitly mention exclusions or alternative tools. It is clear enough for selection in most scenarios.

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