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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed world), and the description adds substantial extra context: amounts are excluding VAT and before discounts, results are per location and for all locations combined, each amount cites its tariff-table source, and the calculation uses the official staffels rather than an estimate. It also discloses the graceful degradation to a from-price when optional inputs are missing.

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 first sentence front-loads the core purpose well, but the text is long and partially redundant: the Dutch use-case enumeration (winkel, kapsalon, praktijk, kantoor, horeca…) is largely repeated in the English paragraph, and the save-with-licence-free-music angle is a second tool's job. Trimming the repetition would sharpen it considerably.

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 no output schema and nine parameters, the description carries the return-value burden and does reasonably well: it states currency basis (excl. btw), granularity (per vestiging and total) and sourcing per tariff table. It does not describe the result object's shape or rounding, which is the only notable gap for a calculation tool.

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 100%, so the schema already documents all nine parameters and the baseline is 3. The description adds genuine semantics beyond the schema: what happens with missing oppervlakte/fte (from-price), the per-location vs total split, and that the saving calculation includes the current subscription — useful behavioural meaning not encoded in the fields.

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 gives a specific verb+resource: calculating annual base tariffs of Buma/Stemra and Sena for background music, with 2026 rates and per/all-location breakdown. It is highly distinguishable from most siblings by subject matter, but it never names or contrasts with neighbours such as check_licentieplicht, pakketten_en_prijzen or vergelijk_opties, so a 5 is not warranted.

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?

Usage context is clear: it is for shops, salons, offices, hospitality, hotels, gyms, pools, saunas and spas, and explicitly says it still returns a from-price when surface area or employee count is unknown. However, it gives no exclusions and does not route the agent to an alternative tool, so it stays below the 'explicit when/when-not/alternatives' bar.

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