Singapore rain now

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

With no annotations, the description carries the disclosure burden and does well: it reveals the geolocation-by-nearest-stations method, the forecast blending, and the island-wide wet-station count. It omits auth/rate-limit facts, but the methodological transparency is a real value-add.

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?

A single front-loaded sentence answers the core question first and then layers sources; no filler, nothing redundant.

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?

No output schema and no annotations, yet the description conveys what the call yields (local rain status, forecast, island-wide count) and how it locates the caller. That covers the essentials for calling it correctly, with only return-format specifics left unstated.

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 all five parameters are already documented in the schema, including the lat/lon, lang, and region semantics. The description adds no parameter guidance beyond that, so the baseline 3 applies.

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?

Answering 'Is it raining near the caller?' plus naming the exact data sources (NEA 5-minute rain-gauge network, nearest three stations, 2-hour area forecast) gives a precise verb+resource. This clearly separates it from get_forecast, get_haze, and weather_now.

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 current-condition usage but never states when to pick this over get_forecast or weather_now, nor any exclusions. Sibling routing is left to inference.

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