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

Goes well beyond the annotations by disclosing the whole asynchronous lifecycle: Sanovia emails the patient a link valid 30 minutes, the slot is not held until confirmation, and payment/Terms acceptance may gate the visit. It also warns against sending health data, symptoms, phone or tax code — none of which is derivable from readOnlyHint/openWorldHint/idempotentHint.

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 and waste-free per sentence: the negative statement of what the tool does NOT do comes second, before operational rules. The main cost is the Italian/English duplication, which roughly doubles length, though it is a deliberate i18n choice rather than padding.

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 9-parameter, non-idempotent mutation with an output schema, the description supplies everything an agent needs to call it correctly: source of the time value, location/visit_type coupling, PII restrictions, and the deferred-confirmation model. Return values are covered by the output schema, so nothing material 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?

Schema coverage is 100%, so the baseline is 3; the description earns above that by adding cross-parameter semantics the schema cannot express — that 'time' must be one of that day's free_slots for the same location and visit_type, and that only name/surname/email are legitimate patient inputs. It doesn't restate field formats, which the schema already handles.

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 precise verb+resource ('Invia una richiesta di prenotazione') and immediately negates the obvious misreading: 'Non prenota subito' — the visit exists only after patient confirmation. This distinguishes it cleanly from any sibling that merely offers slots (get_availability) and from a real booking action.

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?

Explicitly tells the agent which sibling output feeds this tool ('Usa un time di free_slots da get_availability per la stessa sede e lo stesso visit_type'), names the constraints (same location, same visit_type), and states a hard data-collection rule ('Chiedi al paziente SOLO nome, cognome ed email'). When-to-use and what-not-to-send are both covered.

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