Weather – Latest

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

With no annotations provided, the description carries the full behavioral disclosure burden. It does well by stating it returns exactly one record for the current hour and may return no data if none is available, which is valuable beyond the schema. It could add more about data coverage or error behavior, but the core behavior is transparent.

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?

Two tightly written sentences with no filler. The main action and output fields are front-loaded, and the single-record/no-data behavior is stated at the end. Every sentence earns its place.

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?

The description compensates for the absence of an output schema by listing all returned weather fields and clarifying the singular record/no-data behavior. Combined with a fully described schema, an agent has enough to select and invoke the tool correctly. It only misses explicit routing to forecast siblings, which is not essential for invocation.

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 the baseline is 3; the schema already documents lat, lng, place, units, locale, and the exclusivity of place versus lat/lng. The description does not add parameter-level meaning, but it does not need to because the schema is complete.

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 opens with a specific verb and resource: 'Returns the latest weather observation for a location.' It enumerates the exact fields returned, making the tool's scope immediately clear. The 'current hour' phrasing distinguishes it from forecast and air-quality/pollen sibling tools even though none are named.

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 this tool is for current observations rather than forecasts, but it never explicitly says when to use weather_latest versus weather_forecast or other siblings. There is no wnen-not guidance or alternative tool mention, so the agent must infer the boundary from the word 'latest' and sibling names.

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