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

Annotations already establish readOnly, non-destructive, and closed-world behavior, but the description adds substantive context beyond them: the median is service-computed (computed:true), only identical spec/unit/basis are compared, and counts are broken out by price status. It does not discuss auth, rate limits, or pagination, keeping it from 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?

The core purpose and key constraints are front-loaded, and every part of the bilingual text contributes either purpose, comparison rules, or an example. The Japanese and English versions duplicate content, which slightly reduces conciseness.

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?

Given six parameters, an output schema, and annotations covering safety, the description supplies the essential behavioral context: what is aggregated, what may be compared, and how normalization works. It omits explicit country/limit guidance, but the schema covers those details adequately.

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 the structured schema already documents all six parameters. The description still adds value by giving a concrete example and explaining that namacon normalizes ready-mix concrete spec notation across bureaus, which goes beyond the schema's terse enum descriptions.

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?

Names the specific operation (compare latest values across regions), the grouping dimensions (item and spec), and the aggregated outputs (min, median, max, counts by price status). It does not explicitly name or distinguish itself from sibling tools such as get_jccdb_observations, so it falls short of a full 5.

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 comparison purpose implies when to use the tool, and the concrete example (query, spec, layer, normalize) shows a typical invocation. However, the description gives no explicit when-to-use guidance, prerequisites, or alternatives to consider instead.

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