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

Annotations already declare readOnly, idempotent, openWorld=false and non-destructive, so the safety bar is low. The description adds genuinely new behavior context: the tool points to external registers rather than listing firms, and it will never return notaries. That is exactly the kind of coverage limitation an agent needs before calling.

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?

A single dense paragraph front-loaded with the country scoping and closing with the coverage caveat. Almost every clause earns its place, though the parenthetical register lists make it read more like reference notes than a front-loaded summary.

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 one-parameter, no-output-schema lookup tool, the description conveys both what will be returned (where to check, per trade) and what will not (no firm listings, no notaries). Combined with the annotations, an agent has enough to invoke it correctly; only explicit sibling routing is missing.

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?

With one parameter and 100% schema description coverage, the schema already documents 'trade' and its five values. The description restates those values and maps each to its register (Registro Imprese/REA, OAM, geometri, Albo Unico), which is modest added meaning, but nothing about format or validation is supplied beyond 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 concrete resource (the regulator/register for each Italian property trade) and scopes itself to Italy with the 'ITALY.' prefix, which separates it from the check_professional_* sibling family. The action is expressed indirectly ('where the reader checks') rather than as a crisp verb, but an agent can still tell what the tool returns.

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 is implied: use this when you need the Italian regulator/register for one of five trades. The closing note that 'Payotte lists no Italian firm yet and never lists notaries' functions as a partial when-not signal, but there is no explicit routing to alternatives such as trouver_professionnel_fr or verify_license_us.

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