Build a statement of account

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

With no annotations, the description must carry the transparency burden. It usefully discloses output contents, minor-unit formatting, and the free quota/rebuild rule, but it does not reveal side effects, whether builds persist, what output medium is produced, or any auth/permission requirements.

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 dense sentences with no filler: the first front-loads the operation and output components, the second conveys quota behavior. Every clause adds useful information.

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 no output schema, the description does explain what the statement contains and that amounts are in minor units. It falls short by not specifying the output format/medium or how this relates to statement_pdf/statement_text, and it leaves the free/rebuild quota mechanics unexplained.

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 description coverage is 100%, so the input schema already documents client, from, to, and currency. The description adds no parameter-level detail beyond the schema, so the baseline 3 applies.

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 uses a specific verb-resource pair, 'Build one client's statement for a period', and enumerates the statement contents (opening, invoices, payments, credit notes, closing). It clearly explains what the tool does, but it does not explicitly distinguish this from sibling tools such as statement_pdf or statement_text, whose names suggest overlapping statement-generation functions.

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 phrase 'one client's statement for a period' implies a single-client, period-based use case, and the quota note ('Free: 5 a month; a rebuild is free') gives some context on when building may be constrained. However, the description never says when to prefer this over alternatives like statements_report, statement_pdf, or statement_text, nor does it state when not to use it.

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