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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering safety. The description adds behavioral context by stating the data is official JMA open government data, requires no authentication, and covers a 3-day period with specific fields. No contradictions with annotations.

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?

Four sentences, front-loaded with the core purpose, then return fields, then input guidanceanding data source. Every sentence adds value with no fluff.

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 a single optional parameter, a clear output schema presence, and annotations covering safety, the description is complete: it explains what data is returned, how to pass the code correctly, and that no auth is needed. Nothing essential 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 description coverage is 100%, so the schema fully documents the area_code parameter, including pattern, default, and examples. The description repeats the examples and adds the term 'prefecture/region', but this is a minor clarification over 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 clearly states the tool gets an official 3-day JMA weather forecast for a specified area code, and lists the specific data fields returned (weather, wind, waves, precipitation probability, temperature). It distinguishes itself from weather warnings and overview tools by naming the exact resource and scope.

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 instructs the agent to pass a 6-digit JMA area code and explicitly points to jma-bosai.reference.areas for valid codes. It does not explicitly contrast with sibling forecast/warning tools, but the input guidance is clear and actionable.

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