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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds genuine behavioral context beyond them: the forecast horizon, the period-by-period breakdown, the delay-risk rating, and the specific hazard flags (low clouds, storms, snow, strong gusts) that trigger alerts.

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?

Front-loaded with the resource and the horizon, followed by the field list and then the exclusion. A single dense but purposeful sentence plus a short scoping caveat; the detail is justified by the breadth of the output.

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?

An output schema exists, so return formatting is not the description's burden, and the description still previews the fields and hazard flags. What is missing is routing to adjacent siblings and any note on units or code format, but for a one-parameter read tool this is close to complete.

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?

Only one parameter and schema description coverage is 100%, so the schema already documents the accepted IATA/ICAO airport code. The description's only addition is the 'any airport worldwide' scope statement, which is marginal beyond the schema; 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?

Names a specific verb+resource (airport weather forecast), scopes it precisely ('next 24 to 30 hours at any airport worldwide'), enumerates the returned fields (wind, gusts, visibility, cloud ceiling, flight category, delay-risk rating) and the flagged hazards. It is clearly distinguishable from siblings like get_airport_status and get_weather_forecast without opening either schema.

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?

Provides an explicit exclusion ('Not for flight planning') which is real routing guidance, so the agent knows one class of intent this does not serve. However, it names no alternative sibling (get_weather_forecast, get_airport_status, check_trip_delay_risk) for the adjacent use cases it implies.

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