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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds genuinely useful behavioral detail beyond them: kr645 returns rank and prize per winner from the official record, while powerball/megamillions return only the match and omit prize amounts due to state/multiplier variance.

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 tightly packed sentences, front-loaded with the core action and then the per-game output semantics. No filler or restated boilerplate.

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 carries the return-value burden and does explain the key differences per game (rank+prize vs match only). It stops short of describing the actual response structure/field names, but covers the decision-relevant 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 high (75%) and the numbers/extra_number constraints are already documented there. The description still adds meaning the schema lacks: the draw parameter defaults to the latest draw when omitted, which the schema only gestures at with 'Optional, as in get_draw.'

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 specific action ('Compare your numbers with a draw') with the resource (a draw) and notes the default scope ('the latest unless you give one'). It is clearly distinguishable from siblings get_draw and pick_numbers, and even differentiates the per-game behavior in the same breath.

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?

Usage is implied rather than stated: an agent can infer you check tickets after obtaining numbers, and the reference to get_draw hints at the relationship. There is no explicit when-to-use/when-not or routing guidance relative to get_draw or pick_numbers.

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