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

Annotations already cover the read-only, non-destructive, closed-world profile, and the description still adds real behavioral detail beyond them: overdue results are returned oldest-first with a days_overdue field, totals are scoped to the filtered student, and amounts are in BRL. No contradictions 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?

Four tight sentences, each carrying distinct information (return fields, status semantics, student filter, currency), with the core purpose front-loaded. Nothing is redundant or 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?

With no output schema, the description correctly compensates by naming the returned fields and the currency, and it covers all four optional parameters. It does not mention defaults for the date range or any result limits/pagination, which keeps it from fully complete for a list tool.

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, but the description earns extra credit by explaining the semantic consequence of the filters — status 'overdue' adds days_overdue and sorts oldest-first, and passing student narrows the totals to that student. It adds meaning over the raw schema rather than restating it.

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 concrete verb and resource plus the returned fields (amount, student, due/paid date, status), so the agent knows exactly what this returns. It does not, however, distinguish itself from close siblings such as list_student_payments, list_charges or list_subscription_payments, leaving overlap for the agent to resolve.

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 maps each status value to a use case ('overdue' for unpaid past due date, 'open' for anything unpaid, 'paid' for received) and explains when to pass student. It stops short of naming an alternative tool or stating when not to use this one.

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