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

Annotations already declare readOnly/openWorld/non-destructive, and the description goes well beyond them: it mandates that `lat`/`lon` come from `search_place` rather than estimation, states one call per location, explains how multi-day queries map onto `limit`, and adds an anti-fabrication rule plus a legal attribution requirement (GeoNutzV/DWD).

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 one-line purpose before the bolded routing blocks, and every section earns its place. It is dense and mixes German and English, so it is longer than strictly necessary, but nothing is filler.

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 and five parameters, the description still covers what matters: the top-level `attribution` object's shape, the source of forecast values, and the constraint that unlisted days have no value. An agent has everything needed to call and interpret the result.

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 defaults are already documented; the description still adds value by specifying the provenance of `lat`/`lon` and by characterizing `limit` semantically as forecast slots rather than just 'maximum entries'. It adds meaning, though it does not extend the schema substantially.

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 verb+resource (weather forecast for coordinates) and explicitly differentiates from siblings: current conditions go to `get_current_weather`, tides to `get_tide`. An agent can route correctly without opening any 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?

Contains explicit **When to use** and **When NOT to use** sections with concrete example queries in two languages, plus a typical call chain (`search_place` → this tool → optional POI tools). Alternatives are named by tool name, not implied.

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