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

Annotations already declare readOnly, idempotent, closed-world and non-destructive, so safety is covered. The description adds genuinely new behavioral context: results carry the applicable period and an official source, and the year (2026) signals freshness — important since there is no output schema to convey this.

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?

Purpose and freshness rationale come first, then the topic inventory, then the sibling routing rule — a sensible front-loaded order. The topic list is long but earns its place by acting as the human-readable key to the enum; the only slight redundancy is repeating the question-fallback rule already in the schema.

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, the description compensates by describing the return content (amount + period + source), and it clarifies that both parameters are optional alternatives. Nothing critical is missing, though it does not say what happens if topic and question conflict or if a question matches no topic.

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 baseline is 3, but the description goes further by pairing each enum value with a plain-language label (e.g. health_deductible → eigen risico, ind_fees → residence permits and naturalisation), which the raw enum does not provide. It also restates the topic-vs-question precedence, though that is already in the schema.

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 names a specific resource (current Dutch yearly figures), states the payload shape (amount, applicable period, official source), and enumerates all six topics with human-readable labels. It also separates itself from the tax-figures tool, so an agent can place it among its siblings without opening the 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 gives two concrete calling modes ('Ask by topic, or with a short question') and explicitly routes income-tax questions to dutch_tax_figures on the tax server. There is no explicit statement of what this tool should not be used for beyond tax, so it stops short of a full when/when-not map.

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