nws_observation_latest

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds valuable behavioral context by specifying the SI unit system (temperature in °C, wind in km/h, pressure in Pa, visibility in m), which is not in the annotations or schema. This helps the agent interpret the response correctly.

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 sentences, no fluff. The first sentence states the core function with an example; the second lists the return units. Every word earns its place, and the most important information is front-loaded.

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-only tool with one parameter and no output schema, the description is nearly complete. It covers what the tool does, what the parameter means, and what units the response uses. It doesn't describe the full response structure, but with no output schema and a simple observation payload, this is a minor gap.

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 schema already documents the station_id parameter. The description adds a concrete example ('KDCA' for Reagan National Airport) and clarifies the format, which is helpful. It also references nws_stations_near for finding valid IDs, adding routing value beyond the schema.

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 states a specific verb ('Get'), a specific resource ('latest observation from an NWS observation station'), and gives concrete examples ('KDCA', 'KLAX'). It clearly distinguishes this from sibling tools like nws_forecast or nws_stations_near by focusing on the latest observation at a station.

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 when to use it: when you need the latest observation from a specific station. It also points to nws_stations_near in the parameter description for finding station IDs, which is a helpful routing hint. It doesn't explicitly state when not to use it (e.g., for forecasts), but the context is clear enough.

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