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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds genuinely new context: it is free, and it names the upstream sources (DUO, Landelijk Register Kinderopvang), which tells the agent about data provenance and authority. No auth or rate-limit detail, but little is needed for a free read-only lookup.

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?

Front-loaded with "Free. Use when..." so the eligibility and trigger come first. The subsequent clause is a long enumeration of returned fields, which is dense but each item (distance, denomination, pass rates, places) earns its place given there is no output 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 and a single required parameter, the description carries the burden of describing returns and does so exhaustively: school levels, per-school metrics, exam pass rates per track, plus childcare types and registered places. An agent knows exactly what it will get back.

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 description coverage is 100% and the schema itself documents the postcode format with examples (3511LX or 3511). The description adds no syntax or filtering semantics beyond that, so the baseline of 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?

States a specific resource (primary/secondary schools, daycare, after-school care) tied to a specific input (Dutch postcode/address), and the school/childcare focus clearly separates it from siblings like nl_crime, nl_energy_label, or nl_house_prices.

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?

"Use when the user asks about schools near a Dutch address or postcode, or is moving with children" gives explicit trigger conditions. It does not name any alternative tool or state when not to use it, so it falls short of a 5.

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