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

With no annotations, the description carries the disclosure burden and does add real behavior: the default period scope (latest + still-claimable previous) and the digit-length rule that restricts short numbers to sixth prize. It does not disclose what a result looks like (match/no-match, which prize tier) or whether the operation is purely a read, leaving meaningful gaps for a checker tool.

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 compact clauses, front-loaded with the core action, and the default-period caveat follows immediately. The bilingual duplication doubles the length but adds no wasted reasoning; it is efficient for its content.

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?

No output schema exists, yet the description says nothing about what is returned beyond the implicit notion of a prize check, and the period string format is unspecified. Given the low complexity of a two-parameter lookup, this is close to adequate but the missing return-shape and period-format details are real omissions.

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 0%, so the description must compensate for both parameters. It adds genuine meaning for 'number' (3–7 digits limits matching to sixth prize) and for 'period' (omitted means latest plus previous claimable period), but gives no format or syntax for the period value (e.g., 11306 vs 2025-06) and leaves the 8-digit full-number case implicit.

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 states a specific verb and resource: checking a Taiwan invoice (統一發票對獎) against winning numbers. It is distinguishable from sibling invoice_get_winning_numbers by the fact that it checks a user-supplied number rather than retrieving the numbers, though it never names that sibling explicitly.

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?

It gives useful conditional guidance: when no period is specified it checks the latest period plus the previous one that is still claimable, and it warns that 3–7 digit numbers only match sixth prizes. There is no explicit when-not guidance or pointer to invoice_get_winning_numbers for retrieving the prize tables, so routing is implied rather than stated.

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