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

Annotations already declare readOnly, idempotent, closed-world, non-destructive. The description adds useful behavioral context beyond them: it is free (€0), deterministic, requires no login, and the content is verbatim from Gazzetta Ufficiale. It does not describe pagination or exact return shape, but adds real value over the annotations.

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-loads the resource and then the routing target, with the ATECO warning placed where it prevents a costly mistake. It is longer than a minimal description but the legal-rationale sentence earns its place; nothing reads as filler.

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 read-only catalog listing with full schema coverage and annotations covering the safety profile, the description covers purpose, routing, and the key misconception. It does not spell out the return format or pagination, but given no output schema and rich param docs, the omission is minor.

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 all three parameters (`q`, `limit`, `allegato`) are already fully documented, including the enum meanings. The description only restates 'con ricerca testuale' for `q`, adding no syntax or format detail beyond the schema. Baseline 3 applies when the schema does the heavy lifting.

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 verb+resource: an official catalog of NIS2 subject types from Annexes I–IV of D.Lgs. 138/2024, with text search. It explicitly distinguishes itself from siblings by naming its downstream consumer (`nis2_ambito`) and by ruling out the ATECO→tipologia path that `lookup_ateco`/`search_ateco` might suggest.

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?

Gives an explicit purpose: find the `tipologia_id` to pass to `nis2_ambito`. It also states a strong when-NOT-to-use: there is no ATECO→tipologia mapping and this tool does not use one, with the legal rationale. The alternative path is unambiguously excluded.

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