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

Annotations already declare readOnly, openWorld and non-destructive, so safety is covered. The description adds real behavioral context beyond them: hourly model at 1 km resolution, horizon up to 61 hours, the 6-hour block + daily output shape, the CC BY 4.0 attribution footer, and the disclaimer that this is not an official severe-weather warning.

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 core purpose, then variables, then model/limits, then caveat and attribution. The example questions earn their place as usage anchors, though the response-format and license sentences could be tightened.

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 no output schema, the description compensates by enumerating returned fields and the attribution footer, and the annotations cover the safety profile. Missing only explicit sibling routing and pagination/response-size notes, which are minor here.

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 coverage is 100%, so both parameters are fully documented in the schema (ort formats, stunden 1-61, default 48). The description only echoes the 61-hour horizon and does not add syntax or fallback behavior beyond what the schema already states; 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?

States a specific resource and scope: forecast for an Austrian municipality, listing the exact variables returned (temperature min/max, precipitation, snow share, gusts, wind, snow line) plus daily values. However, it never names or distinguishes itself from close siblings like niederschlag_jetzt or lage_am_ort, so the agent must infer the boundary.

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 example questions ("Regnet es heute Abend in Steyr?", "Wie warm wird es morgen in St. Pölten?") give concrete use contexts, and "Keine amtliche Unwetterwarnung" sets a when-not boundary. But no alternative tool is named for cases the agent might actually want (e.g. current precipitation or flood levels).

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