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

Annotations already declare readOnlyHint=true, idempotentHint=true, and non-destructive, so the safety profile is covered. The description adds little beyond reiterating that regions overlap data; it does not explain the minAxes filtering behavior, output format, or why 'check here first' matters. With the low bar set by rich annotations, this still under-delivers.

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?

The description is short and front-loads the core idea, which is good. However, the bilingual duplication doubles the length without adding information, and the second sentence after the slash is just a Korean translation rather than new guidance.

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 simple one-param, read-only list tool with no output schema, the description is minimally adequate: it tells the agent this is a starting point for region availability. It still lacks clarity on what the returned list contains and how minAxes changes it, leaving some gaps.

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% and the single parameter minAxes is fully documented in the schema, including its default and meaning. The description adds no extra meaning about how minAxes affects the result set, so 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 resource (Korean districts / 시군구) with a qualifier (where several kinds of data overlap), which is more precise than a bare 'list regions'. It does not, however, mention the sibling region_overview or distinguish scope from that tool, so sibling differentiation is missing.

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?

The phrase 'Check here first' implies a recommended entry point, which hints at when to use it, but no explicit when/when-not or named alternatives are given. An agent gets a soft suggestion rather than a clear routing rule.

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