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

Annotations already carry the safety profile (readOnlyHint, idempotentHint, non-destructive), so the bar is lower. The description adds context beyond them: the paid ([유료]) nature of the call, the distance-sorted behavior, and the coordinate-search scope limited to 3 POI types. It does not describe the return shape, but there is no contradiction with annotations — behavioral coverage is solid.

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 dense sentences with front-loaded purpose, then the input-source note, then a bolded decision rule ('**점수**만 필요하면... 이 도구는 실제 시설 목록·거리를 셀 때'). Every sentence earns its place; no filler or restatement of schema contents.

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?

For a 4-parameter, read-only, fully schema-documented lookup, the description covers the essentials: what it returns (facility list by distance), when to use vs. realty_location_scores, and cost. The only gaps are the exact response structure (no output schema exists) and a minor internal wobble where '마트' appears in the description though coordinate search only supports 3 types — the schema's poi_type description promptly resolves the latter.

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 100% and every parameter is already well documented in the schema: lat points to realty_complex_report.latitude, lng is self-explanatory, poi_type lists the allowed tokens ('subway,school'), the default, and the regional-stats fallback, and radius_m carries default/min/max. With the schema doing the heavy lifting, the description adds little extra parameter meaning, so the baseline 3 applies.

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: '좌표 주변의 지하철·학교·병원·마트 등 입지 요소를 거리순으로 조회한다' — a coordinate-based facility lookup ordered by distance. It also names what it is not via the sibling realty_location_scores (scores verdict) and realty_poi_stats (regional stats), so an agent can discriminate without opening either 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?

Decision guidance is explicit: '단지의 학군·교통 **점수**만 필요하면 무료 realty_location_scores로 충분하다 — 이 도구는 실제 시설 목록·거리를 셀 때 쓴다'. The poi_type schema description also routes non-supportable types (마트·약국) to realty_poi_stats, and the description names the input source ('단지 좌표는 realty_complex_report가 준다'). This is exemplary when-to-use vs. alternative guidance.

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