get_weather_forecast

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the agent knows this is a safe read operation with open-world assumptions. The description adds useful context about the geographic scope ('Japanese city') but doesn't provide additional behavioral details like rate limits, error conditions, or response format.

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, efficient sentence that communicates the essential information without any wasted words. It's appropriately sized for a simple tool with one parameter and good annotations.

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 read operation with good annotations (readOnlyHint, openWorldHint) and 100% schema coverage, the description provides adequate context. However, without an output schema, it doesn't describe what the forecast response contains, which would be helpful for agent planning.

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% with the cityId parameter fully documented in the schema. The description adds minimal value beyond what's already in the schema - it mentions 'using city ID' but doesn't provide additional syntax, format, or usage details. Baseline 3 is appropriate when schema does the heavy lifting.

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 specific action ('Get weather forecast'), the resource ('for a Japanese city'), and the method ('using city ID'). It distinguishes from sibling tools by specifying the city ID parameter approach rather than city name or available IDs.

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 clear context about when to use this tool ('using city ID'), which implicitly suggests alternatives like the sibling tool 'get_weather_by_city_name'. However, it doesn't explicitly state when NOT to use this tool or provide explicit comparison guidance.

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