update_payment_account

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

The single annotation is idempotentHint=true, so the description must carry most of the behavioral burden for a mutation. The partial-update promise (only changed fields are sent) usefully implies untouched fields are preserved, but validation of iban/sia/cuc, permissions, reversibility, and error behavior are all undisclosed. Nothing contradicts the idempotent annotation.

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 sentences, front-loaded with the action and target, then the patch instruction, then a compact field list. Every clause carries information an agent needs and there is no 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 mutation tool whose nested object is schema-opaque, the field enumeration is the essential missing piece and it is present. Remaining gaps are minor but real: no return information (no output schema exists) and no statement about validation failures or whether company_id scoping changes behavior.

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 only 33% and the required "data" property is an unconstrained free-form object, so the schema alone tells an agent nothing. The description compensates by enumerating exactly which keys go inside data (name, type, iban, sia, cuc, virtual) and by giving the type enum values standard/bank, which the schema lacks. It stops short of describing value formats or the id parameter.

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?

"Modifica un conto di saldo (banca, cassa, carta) su cui registrare incassi e pagamenti" gives a specific verb plus the resource, and the parenthetical names the concrete account kinds. It contrasts with create/delete/list siblings only through the verb, with no explicit routing statement, which keeps it at 4 rather than 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?

"passa solo i campi da cambiare" is a real calling guideline that tells the agent to send a sparse patch, not a full object. However, it never says when to choose this tool over create_payment_account or delete_payment_account, nor what prerequisites exist (e.g. account must already exist), so usage is only implied.

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