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

Beyond the readOnly/non-destructive annotations, it discloses three things an agent could not infer: results exclude Employer of Record fees, rows return in request order rather than ranked, and the data is a dated snapshot. It also adds a scope disclaimer ('cost comparison, not legal or tax advice') that matters for how an agent frames the answer.

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?

Roughly five short sentences, zero filler. The core intent and the numeric scope lead, then the sibling exclusion, then the caveats — a well front-loaded structure where every sentence carries information.

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?

With an output schema present and annotations covering safety, the description supplies exactly the missing layer: scope boundaries, the sibling decision rule, data currency, and exclusions from the returned figures. Nothing an agent needs in order to call this correctly is absent.

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 coverage is 75%, with countries, salary_usd and salary_period already well documented in the schema. The description reinforces the 2–10 country bound and the 'same salary applied to all' semantics, but adds nothing about salary_period or payments_per_year beyond what the schema says, so the baseline 3 applies.

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 and resource — the statutory employer cost of one identical gross salary across 2 to 10 countries — and gives a concrete example. It also explicitly distinguishes itself from the closest sibling (compare_offers) so an agent can route without opening either 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?

It names the triggering intent with natural-language examples in two languages, and states an explicit exclusion rule: 'Do not use when each country has its own salary (use compare_offers).' That is a when/when-not/alternative triple.

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