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

Beyond the annotations (which only declare read-only and closed-world), the description discloses the actual computation rule (5% reduction per year starting at car-age year 3, capped at 50%), what the result contains (자동차세·지방교육세·합계), and crucially an unusual per-call cost of 60 points. Cost and calculation logic are meaningful behavioral traits an agent cannot get from structured fields.

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 purpose, then reduction logic, exclusions, and cost in tight sentences. The Korean text is not a duplicate of the English but carries additional detail (the reduction schedule and exclusions), so it earns its space.

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?

There is no output schema, yet the description names the three returned figures, so the agent knows what comes back. For a 3-parameter, read-only calculator with full schema coverage, nothing needed to invoke or interpret it is missing.

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% with ranges and defaults already documented, so the baseline is 3. The description adds real semantic meaning for car_age_years by explaining how vehicle age drives the 5% annual reduction, which the schema does not convey. It says nothing extra about the year parameter, keeping it from a 5.

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 names a specific verb (calculate) and a well-scoped resource (annual Korean automobile tax for a non-commercial passenger car), and lists the two driving inputs. This clearly separates it from siblings such as vehicle_emission, vehicle_recall, and vehicle_model_info, without needing to open the schema.

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 lists when NOT to use it: '연납 공제·감면·영업용 차량은 계산하지 않습니다' (no annual prepayment deduction, no reductions/exemptions, no commercial vehicles). It also implies the eligible use case (non-commercial passenger cars), but it never names an alternative tool for the excluded cases, so it stops short of a full 5.

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