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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=false, so safety is covered. The description contributes beyond that by characterizing the return values as live, current-state counters matching the homepage ('실시간 숫자'), which explains why repeated calls may differ and is consistent with idempotentHint=false. It does not discuss auth, freshness lag, or caching, hence not a 5.

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 short sentences: the first front-loads the metric list, the second adds the single most important property (live, homepage-equivalent figures). Every clause carries distinct information and there is no filler or repetition of the title.

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?

With no parameters and no output schema, the description must carry the return-value burden itself, and it does so by naming each metric the caller will get. For a simple read-only aggregate endpoint this is complete; an agent knows exactly what comes back and that the numbers are current.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; baseline 4 applies. The description does not need to compensate for any schema gaps, and it uses the space instead to enumerate return metrics.

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 names the resource ('카볼트랩이 지금까지 읽은 배터리') and enumerates the exact metrics returned: cumulative inspected vehicles, cumulative mileage, reset-trace determination count, latest inspection date. That is a specific verb-plus-resource statement an agent can act on. It does not, however, contrast itself with siblings like carvoltlab_report_items, so it falls short of full sibling differentiation.

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?

Usage is implied rather than stated: the agent can infer this is the tool for aggregate/cumulative figures, and '홈페이지 실적과 같은 실시간 숫자' hints at the authoritative live source. There is no explicit when-to-use, when-not-to-use, or named alternative among carvoltlab_report_items, carvoltlab_battery_checklist, or carvoltlab_faq. Nothing is misleading, but routing is left to inference.

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