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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the safety profile is covered. The description adds behavioral value by stating the output is counts per dataset kind and that it serves as a precursor to search_data. It does not go into detail about what happens when sigungu is omitted, but that is a minor gap given the annotations.

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 concise English sentences, each earning its place: the first defines purpose and output, the second gives usage context and a pointer to the next step. The Korean translation is redundant but not harmful and is a common practice for regional tools. No filler or unnecessary detail.

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?

The description clearly covers the return type (counts per dataset kind) and directs to search_data. However, the optional sigungu parameter is not explained behaviorally: the description implies a single city/district, but does not state what happens when sigungu is omitted (e.g., province-level rollup). This is a meaningful gap for correct invocation, but not severe given the tool's simplicity and the schema's note that sigungu is optional.

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%; both parameters (sido and sigungu) have clear descriptions in the schema. The description only adds the phrase 'one Korean city or district' which aligns with the schema but does not provide extra syntax or format details. Baseline 3 is appropriate as the schema already carries the parameter 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 description states a specific verb-resource pair: 'See at a glance what kinds of data we hold for one Korean city or district, and how many records of each.' It also clearly differentiates from search_data by stating it returns counts per dataset kind rather than detailed records, making the tool's role unmistakable.

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 description explicitly provides usage context: 'Good as a first look before planning a trip or a site survey.' It also names the alternative tool and directs the agent to it: 'so you can then drill in with search_data.' This gives clear when-to-use and follow-up guidance.

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