list_vat_rates

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

No annotations are provided, so the description carries the full disclosure burden. It does reveal useful behavior — the result spans all supported countries and is sorted by rate — but says nothing about read-only safety, auth requirements, or whether the list is exhaustive/cached. Adequate for a trivial zero-param read, but not rich.

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?

Two short sentences, zero filler, with the scope and ordering constraint front-loaded before the use case. Every clause 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 zero-param listing with no output schema, the description covers what is returned (all countries, sorted) and a typical use case. It is nearly complete; only the relationship to get_vat_rates and the return shape remain unstated.

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 tool takes zero parameters, so there is no parameter semantics to explain; baseline 4 applies. The description correctly implies no filtering input is needed since rates are returned across all countries.

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?

States a specific verb and resource with scope: 'List VAT standard rates for all supported countries, sorted by rate.' The 'all supported countries' scope implicitly contrasts with the sibling get_vat_rates (singular lookup), but the description never names that alternative, so sibling differentiation is left to inference.

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?

'Useful for comparison' hints at when to reach for this over a single-country lookup, but there is no explicit when-to-use statement, no exclusion, and no named alternative (get_vat_rates) despite it being an obvious sibling.

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