singapore_get_uv_index

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld, so the safety profile is covered. The description adds genuinely non-obvious behavior: Singapore-local date semantics, timezone-sensitive grouping of limits, and a preserved upstream pagination token that must be carried forward with local offsets consumed first. That is real added context, but the pagination sentence is cryptically worded and the return shape is left to the output schema.

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?

It is short and front-loads the resource identity, so it is not padded. But the final sentence ('Consume local offsets before continuing the preserved upstream pagination token') is dense and ambiguous rather than informative, and 'Local limits apply to timestamp groups' is opaque phrasing that costs the reader more than it gives.

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 seven parameters, zero required fields, an enum region, and no schema descriptions, the description needs to carry more weight than it does. The output schema and annotations cover returns and safety, but an agent still cannot tell what area/station_id/region mean or how filtering composes, so the definition is not complete enough to invoke confidently.

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 only 14% – just the date field is documented in the schema. The description only additionally clarifies the date default ('latest if omitted') and vaguely references the pagination_token. Six other parameters (area, region, station_id, limit, offset, and how area relates to region) get no explanation anywhere, which is a substantial compensation gap.

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 identifies the resource ('NEA UV index') and the source agency, which distinguishes it from siblings like singapore_get_air_temperature or singapore_get_rainfall that cover other measurements. However, it never states an explicit verb or scope (single station vs. national, point-in-time vs. series), so the purpose is only implied by the tool name rather than elaborated.

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?

It says what happens when date is omitted ('latest if omitted'), which is a small usage hint. But there is no guidance on when to choose this tool over the other weather siblings (PSI, PM2.5, forecasts), no required-vs-optional framing, and no exclusions. Usage must be inferred from the name alone.

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