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

Annotations already declare readOnlyHint and idempotentHint. The description adds valuable context beyond annotations: it requires an API key, does not consume credits, and specifies what the last check includes (VIES outcome, authoritative flag, elapsed time, anomalies). No contradiction with 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?

The description is two sentences and front-loaded. The first sentence directly states purpose and output details; the second covers requirements and cost. No unnecessary words, perfectly concise.

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 read-only tool with two well-documented parameters and no output schema, the description fully explains what the response contains (VIES outcome, authoritative status, time since last check, anomalies) and prerequisites (API key, no credits). Combined with annotations, this is complete.

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%, with descriptions for both parameters (`partita_iva` and `codice_fiscale`). The description adds minimal context beyond the schema, mainly that the tool operates on a supplier within the account (implicitly linking parameters to the account). It does not clarify the anyOf relationship, but the schema already covers that. Baseline 3 is appropriate.

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 clearly states the tool tells whether a supplier is monitored ('sorvegliato') by the account and details the last verification (VIES outcome, authoritative response, time since last check, anomalies). It uses a specific verb ('Dice') and names the resource (supplier status), distinguishing it from siblings like guardian_watch_supplier or guardian_list_suppliers.

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?

The description gives clear context: it is for checking surveillance status and last verification details. It also notes the prerequisite of an API key and that the operation does not consume credits. It does not explicitly name alternatives or exclusion criteria, but the context is sufficient for an agent to decide when to use it.

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