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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description usefully adds data provenance (dhlottery.co.kr, data.ny.gov), which is genuine extra context, but it says nothing about behavior on an invalid draw number/date or what the response contains.

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?

Three compact sentences, front-loaded with what is returned, then the argument format, then sources. No filler; every clause carries usable 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?

With no output schema, the description states what is returned and how the single required enum plus optional draw argument behave. That covers everything an agent needs to invoke this simple read tool correctly.

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 only 50% (the game enum has no schema description), and the description compensates by mapping each enum value to its required argument form and its source. It adds real semantics beyond the schema, though it largely restates the draw field's own description.

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 verb+resource ('the winning numbers of the latest draw, or of one past draw') with clear scope. It is implicitly distinguishable from check_ticket and pick_numbers, but the description never names or contrasts with those siblings, so the differentiation is left to inference.

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?

Gives clear conditional usage for the optional draw argument ('kr645: give the draw number (회차). powerball, megamillions: give the draw date YYYY-MM-DD') and explicitly says 'Leave it out for the latest.' That is strong how-to-use guidance, but there is no when-to-use-this-vs-siblings advice.

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