list_credit_card_bills

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

Beyond the annotations (readOnlyHint, openWorldHint), the description adds a meaningful behavioral nuance: the returned bills do not represent all current debt. This helps the agent interpret the limited scope of results. It doesn't cover other behaviors like pagination, but annotations already signal read-only and open-world characteristics, so the added context is valuable.

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 a single, concise sentence with no filler. It front-loads the main concept ('bills from an authorized card') and then attaches a clarifying caveat. Every word contributes to the meaning, exemplifying efficient structure.

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 tool with only one parameter, annotations covering read-only and open-world, and an output schema, the description is adequate but not rich. It conveys the core function and a key caveat, but lacks details on what constitutes a 'bill' (e.g., period, status) or how to obtain comprehensive debt information. The caveat is helpful, but the description could be more complete about the exact return content and edge cases.

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?

The only parameter is account_id (uuid), and schema description coverage is 0%, so the description should compensate. The description does not explicitly describe the parameter, but the phrase 'cartão autorizado' implies the account must be an authorized credit card, giving some semantic hint. Since the parameter's name is self-explanatory and it's a single UUID, the description adds marginal but not strong value.

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 the resource (credit card bills) and a scope (authorized card), which combined with the verb 'list' in the tool name makes the purpose reasonably clear. However, it lacks an explicit verb like 'retrieve' or 'return', and the phrasing is more of a noun phrase. It does distinguish from the singular sibling get_credit_card_bill by implying a collection, so purpose is understandable but not perfectly explicit.

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 includes a cautionary note that these bills do not represent all current debt, which implies the tool should not be used to get a total debt figure. However, it does not explicitly mention alternatives (e.g., get_total_balance) or provide clear when-to-use/when-not-to-use conditions. The guidance is implicit rather than explicit.

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