weather_forecast

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

Annotations already mark this as read-only and open-world, so the bar is lower. The description adds behavioral context by disclosing the forecast time horizons (today, near-term, 7-day) and the data source (JMA), which goes beyond the annotation information.

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 a single, tightly packed sentence that front-loads the purpose and includes content scope and source. Every element earns its place with no wasted words.

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 tool with read-only annotations and no output schema, the description is sufficiently complete. It covers what the tool returns and the source, though it does not describe return formatting or possible area input syntax—those are delegated to the schema.

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 input schema already fully describes the 'area' parameter as a JMA office code or Japanese/English region name (100% coverage). The description only repeats 'region' without adding extra meaning, meeting the baseline for high schema coverage.

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 provides a Japanese weather forecast for a region, including today's conditions, near-term outlook, and a 7-day forecast. It implicitly distinguishes itself from sibling tools like weather_warnings and weather_areas by focusing on forecast content, though it lacks a direct verb like 'returns' or 'provides'.

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 implies usage for obtaining weather forecasts but does not explicitly state when to use this tool over alternatives such as weather_warnings or weather_areas. No exclusions or alternative tool references are provided.

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