Singapore 2-Hour Weather Forecast

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

Annotations already declare the tool as read-only, non-destructive, idempotent, and open-world. The description adds that it is real-time and from NEA, but does not disclose any behavioral traits beyond what annotations already provide. No contradictions.

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 sentence followed by a license note, which is concise and front-loaded with the key purpose. It could be slightly more structured, but it is efficient and clear.

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 tool with one optional parameter, an output schema, and comprehensive annotations, the description covers the source, coverage, and license. It is fairly complete, though it could mention what the output contains or the update frequency.

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 has 100% coverage for the single parameter 'date', with its own description. The tool description adds no additional meaning to the parameter; it does not explain the effect of providing a date versus omitting it. Baseline 3 is appropriate.

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 that the tool provides a real-time 2-hour weather forecast for 51 Singapore zones, sourced from NEA. It indicates the type of forecast (showers/cloudy) and licensing, which makes the purpose clear. However, it does not explicitly differentiate from sibling tools like gov.sg.air_quality or gov.sg.rainfall, so it's not a perfect 5.

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?

No guidance is provided on when to use this tool versus alternatives. It does not mention prerequisites, limitations, or scenarios where this tool is preferred. The description is purely functional without context.

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