vat_calc

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

With no annotations, the description carries full responsibility for disclosing behavior. It only mentions cost, omitting any information about inputs, outputs, side effects, or whether it is a read-only calculation. This is a severe transparency gap.

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 extremely short, but the two sentences do not earn their place: 'Other Utilities tool' is a vague category and the cost line, while factual, is not a substitute for functional information. This is under-specification rather than effective conciseness.

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?

Given the minimal schema, absent annotations, and lack of output schema, the description should provide substantial context. It does not, leaving the tool's purpose, usage, and behavior almost entirely undefined.

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 only defines a generic 'params' object with no meaningful property documentation. The description adds zero information about what parameters vat_calc accepts, so the 100% schema coverage is misleading and the tool's actual inputs remain completely unspecified.

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 restates the tool name ('vat calc') and labels it 'Other Utilities tool' without stating what it actually does. It fails to mention that it calculates VAT or any specific function, making it nearly tautological.

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?

No guidance is provided on when to use this tool versus alternatives like validate_vat or other calculation tools. The description lacks any context about appropriate use cases or exclusions.

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