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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the safety profile is covered. The description adds that the tool both validates and formats, which is useful beyond the annotations, but it does not explain what formatting means or what the result contains.

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 no wasted words. It communicates purpose immediately and is appropriately sized for a simple one-parameter validator.

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 validation tool this is adequate for selection, but with no output schema the description leaves unclear what validation and formatting actually return or how failures are represented. It is minimally complete rather than fully informative.

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 100%, so the single 'value' parameter is already documented in the schema with an example ('123456-6'). The description adds no syntax, normalization, or input constraints beyond the schema, so the baseline of 3 is appropriate.

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 pair ('Validate and format') and a precise resource ('Swedish plusgiro number'). The resource itself distinguishes it from sibling validators like validate_bankgiro and validate_orgnr, though no sibling is named explicitly.

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?

There is no guidance on when to use this tool versus alternatives such as validate_bankgiro or lookup_clearing_number, and no prerequisites or exclusions are stated. The sibling list implies a domain-specific validator, but the description itself provides no routing guidance.

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