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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds valuable context by stating the output is official Japanese text, includes a headline and narrative, requires no auth, and comes from open Japanese government data. This supplements the annotations without contradicting them.

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 composed of three focused sentences that front-load the purpose and return value, then give usage and data-source notes. It is appropriately sized, though the parameter examples in the description slightly duplicate schema content.

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?

For a simple one-parameter, read-only tool with an output schema, the description covers the essential operational details: input format, return shape, language, authoritative source, and auth requirement. The output schema handles return-structure specifics, so nothing critical 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?

The single parameter is already 100% covered by the schema, which includes pattern, default, common codes, and a reference to jma-bosai.reference.areas. The description repeats the same examples (130000, 270000) without adding new semantic meaning beyond what the schema already provides.

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 uses a specific verb ('Get'), names the resource ('official meteorological overview text from JMA'), and specifies the input ('specified area') and return shape ('headline and a full narrative weather summary in Japanese'). It clearly distinguishes itself from sibling forecast/warning tools by emphasizing the narrative, officially issued JMA text.

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 a usage context ('Useful for understanding the weather situation context beyond just codes and temperatures') but does not explicitly name alternatives or state when not to use this tool. Guidance about choosing between this and jma-bosai.weather.forecast or jma-bosai.weather.warnings is only implied, not explicit.

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