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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, openWorldHint=true), but the description adds the non-obvious behavioral fact that ordering is editorial weight rather than traffic — a ranking semantic an agent could not infer from structured fields. It stops short of stating the time window implied by '오늘' or how many items are returned.

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 sentences, zero filler: the routing trigger comes first, the exclusion second. The example phrasings earn their space because they map directly to how an agent would match a user utterance.

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 an output schema present, return values need no explanation, and the safety profile is annotation-covered. The only real gap is the freshness/time window behind '오늘' (same-day only? rolling 24h?), which an agent calling a headline tool would reasonably want.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. No misleading parameter hints are present.

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 resource (편집부가 가장 비중 있게 배치한 머리기사) and immediately disambiguates it from a superficially similar sibling (list_popular_news). An agent can distinguish this from list_most_read_news or list_popular_news without opening any schema.

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 concrete trigger phrasings ('오늘 주요 뉴스', '지금 헤드라인', '메인 뉴스 뭐야') plus an explicit exclusion rule routing '많이 본' queries to list_popular_news. Both the when and the when-not are named.

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