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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description's 'Assess' action aligns with this. The description adds scope details (3 axes, 10 prefectures) but does not disclose return format, error behavior, or limitations. Since the annotations carry the safety profile, the description adds some value but not rich behavioral context, earning a 3.

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 description is brief and front-loaded: it states the verb and scope in the first clause, followed by the axes and scale. The Japanese duplicate is redundant for English-reading agents but does not harm. No wasted sentences, and the structure is efficient.

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 6 parameters, one required, a nested object, no output schema, and no parameter explanations, the description is insufficient. It does not clarify what 'area' refers to (prefecture vs. arbitrary region), which prefectures are covered, or what the output looks like. An agent would need to infer too much to call this tool correctly.

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 67%, and the description adds no parameter-specific information. It does not explain what 'area' means, how latlng or childAge are used, or how the optional parameters affect the assessment. The description leaves parameter semantics entirely to the schema, which is only partially documented. Since coverage is below 80%, the baseline is raised, but the description does not compensate.

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 clearly states the tool's purpose: 'Assess family-friendliness' with specific axes (education, safety, healthcare) and a scope (10 prefectures). It is not a tautology and gives a distinct functional identity. However, it does not explicitly differentiate from sibling tools like compare_prefectures or drill_down_local_analysis, which could also involve area assessment.

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 provides no guidance on when to use this tool versus alternatives. It states what it does but does not mention any conditions, exclusions, or situations where another sibling tool would be more appropriate. An agent gets no context for selection beyond the tool's name.

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