get_weather_forecast

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

Despite no annotations, the description fully discloses key behaviors: data source (scraped from vedur.is), regional coverage, and fallback to national text forecast with a 'degraded' marker on failure. No destructive or side effects are omitted.

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?

The description is a single, well-structured paragraph. The first sentence states the primary purpose, and every subsequent sentence adds essential detail (variables, scope, fallback) without redundancy.

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 tool with no output schema, the description lists returned variables and mentions the fallback behavior. It is mostly complete but lacks explicit details on output structure or station ID usage, though the schema covers the latter.

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% with each parameter already documented (lang, hours, stations). The tool description adds minimal extra meaning beyond reiterating the fallback language, so baseline score of 3 is appropriate.

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 clearly states it retrieves multi-day hourly forecasts for Iceland, specifies the variables (temperature, wind, etc.), and distinguishes it from siblings by highlighting the granularity and regional scope.

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 use for detailed hourly forecasts but does not explicitly state when to use this tool instead of siblings like get_weather_now or get_weather_text. No exclusion criteria or alternative guidance is provided.

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