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

Beyond the readOnly/openWorld annotations, the description discloses non-obvious behavior: stations, nicknames and landmarks return a center plus radiusM and no region_code, and ambiguous names yield multiple candidates that the agent should disambiguate or ask about. It stops short of covering failure modes (unknown names, empty results) and how candidate lists are ordered.

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 core purpose, then stacked with usage examples in descending priority; every sentence carries operational information. The dense multilingual example clusters slightly hurt scanability, but there is no filler.

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 burden of return-shape disclosure and does partially: it names region_code, center coordinates, venue count and radiusM as outputs. A mutation-free read tool with full schema coverage needs little more, though a brief note on result ordering or empty-result handling would close the last gap.

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%, so the schema already defines all five parameters, making baseline 3 appropriate. The description does add genuine meaning beyond it — landmarks and station names go into `dong`, a whole city or province goes into `sido`, romanized names are accepted — but it never touches `region_code` lookup or `include_empty` semantics.

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 first clause names a specific transformation and its outputs: place name → region_code, center lat/lng, venue count. It also enumerates the accepted input classes (admin areas, subway stations, nicknames, landmarks), so an agent knows exactly what this tool resolves and how it differs from search_places or nearby_places.

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?

Explicit routing guidance is given: use this to get coordinates for nearby_places, but for a normal search pass region_name to search_places instead. It further specifies which parameter each input class belongs in and warns against inventing codes or coordinates, leaving no inference required.

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