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

With no annotations, the description carries the full burden and does so well: it discloses the data source and monthly SKT-based aggregation, the non-real-time nature, the behavior when region is omitted, automatic mapping between 행정동 and 법정동 names, and the no_data/available_regions fallback path. It even tells the agent to surface page_url as a source link, which is behavior beyond any structured field.

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?

Purpose and scope are front-loaded in the opening sentence, followed by source/caveats, default behavior, naming behavior, error handling, and link guidance in a logical order. Every sentence carries operational value; 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?

For a single optional parameter with no output schema, the description covers everything an agent needs: what is returned, the shape of the default call, the no_data contract with available_regions, and the page_url field. Missing structured return documentation is compensated for by describing response fields in prose.

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 a baseline of 3 already applies, but the description adds real meaning: legal-dong names (용담이동) are auto-mapped to the platform's administrative-dong notation (용담2동), and omitting the parameter returns the full list. This is semantic behavior the schema does not convey.

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 sentence states a specific verb+resource+granularity: monthly visitor statistics by 읍면동, with domestic/foreign split and month-over-month/year-over-year comparisons. It is clearly distinguishable from sibling stats tools (get_site_stats, get_ad_stats, get_price_stats) because the tourism/visitor domain and the geographic unit are named explicitly.

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?

It gives strong usage context: the data is not real-time, so the agent should describe monthly patterns rather than 'crowded right now', and an omitted region returns the whole township list for the latest month. It does not explicitly name sibling tools to use instead for real-time crowding (e.g. find_quiet_spots), so routing guidance is implied rather than complete.

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