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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so the safety profile is covered. The description adds only the implicit signal that this is stable 'reference data'; it says nothing about result size, pagination, or whether region/province filters are exact-match or fuzzy.

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 compact sentences with zero filler; the resource scope is front-loaded and the filter applicability follows immediately. Every clause 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?

For a simple, fully-specified read-only lookup tool with 100% schema coverage and clear annotations, the description covers what the agent needs. No output schema exists, but the return value (a list of administrative names) is self-evident; only minor gaps like filter matching behavior remain.

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%, so the baseline is 3. The description's filtering note ('provinces by region, municipalities by province or region') merely restates what the schema parameter descriptions already say, adding no syntax, format, or matching-behavior detail.

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 the exact resource set (Italian administrative reference data) and enumerates the three variants (regions, provinces, municipalities), matching the enum in the schema. It clearly differentiates from the geocoding and parcel siblings. It lacks an explicit verb like 'list'/'return', which the title supplies, so it falls just short of a 5.

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 states which filters apply to which type ('Provinces can be filtered by region; municipalities by province or region'), which is usage guidance for parameters. However, it gives no when-to-use vs. alternatives guidance — e.g. that this is static lookup data rather than geocoding — and no exclusions.

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