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

Goes well beyond the readOnly/idempotent annotations: discloses the data source (관보 원문 대조), the coverage start date, the exact fields returned (효력일·공고일·공고번호·범위·관보 출처), and the deliberate '부분 지정' behavior when 읍면동·지구 단위 공고 applies rather than guessing. That is exactly the kind of result-shaping behavior an agent needs before calling.

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?

Front-loaded with the resource and scope, and each following sentence adds distinct value (caveat about 부분 지정, redirect to tax-law sources). It is dense and slightly long as a single block, but nothing is redundant.

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-shape burden and does so by enumerating the fields and their meaning. Combined with annotations covering safety, an agent has everything needed to call it and interpret the answer 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 100%, so the baseline is 3; the description still adds value by explaining what as_of actually governs (the designation state as of that date, defaulting to today) and by tying partial-scope designations to that evaluation. The region granularity '시군구별' also clarifies expected input shape beyond the schema examples.

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 and resource — returns the designation/release history of 조정대상지역·투기과열지구·투기지역 by 시군구 — plus scope boundaries (since 2017-08-03, based on 관보 원문, explicitly '세법 아님'). The 'not tax law' framing separates it cleanly from the tax-law siblings like get_article/search_tax.

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?

Clearly says when to use it (historical designation status as of a given date) and when not to (중과·거주요건·계약 예외 등 세법 효과는 세법 조문으로 확인), which routes the agent elsewhere. It stops short of naming the specific sibling tool to use instead, so the redirect requires inference.

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