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

Annotations already declare readOnlyHint and openWorldHint, and the description adds real cost information ([호출당 60포인트]) plus a key output caveat that amounts and toll details are not provided. That is meaningful behavioral context beyond structured fields, though it omits latency or data-freshness characteristics.

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-loads the core purpose and keeps the cost and exclusion notes brief. The English/Korean duplication slightly inflates length, but each line still carries distinct operational information.

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?

No output schema exists, and the description compensates by explaining the returned unpaid_target flag and unpaid count, plus what is not returned. Per-call cost is disclosed; only edge-case behavior for invalid plate formats is left unstated.

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?

With 100% schema coverage on the single car_no parameter, the schema already carries the plate-number semantics and examples. The description only restates 'by plate number', so baseline 3 is appropriate.

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?

States a specific verb+resource: checking unpaid Hi-pass expressway tolls for a Korean vehicle by plate number. The resource is distinct from vehicle siblings like vehicle_recall or vehicle_tax_calc, although the description never names those alternatives to sharpen the boundary.

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?

Gives clear scope and an explicit exclusion: it will not return unpaid amounts or toll usage history, and if unpaid_target=false no charge applies. Missing is any direct routing statement comparing it against the other vehicle_* siblings.

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