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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint=false. The description adds valuable behavioral details: no distance filter by default (returns all stations sorted by proximity) and no API key required (open DWD data via Bright Sky, MIT licence). These go beyond the annotations and help the agent understand side effects and prerequisites.

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 concise paragraph of four sentences. It front-loads the core purpose, lists return fields, provides a use case, and mentions default behavior and licensing. Every sentence adds value with no redundancy or 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?

Given the tool has an output schema, the description does not need to explain return structure. It covers the tool's purpose, return fields, use case, default behavior, and licensing. It omits pagination/limit details, but these are likely in the output schema, and the description is sufficient for an agent to decide when to call it.

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%, and each parameter is documented with meaning (latitude/longitude ranges, max_dist optional with default behavior). The description repeats the max_dist default but does not add new semantic information beyond what the schema already provides, so the baseline 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 the tool finds DWD weather stations near a given latitude/longitude in Germany, listing the specific fields returned (station ID, WMO ID, name, coordinates, elevation, observation type, date range, distance). It distinguishes itself from weather data tools by explicitly mentioning it is for discovering stations before querying observations or synop data, making its purpose unambiguous.

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 provides clear context on when to use it ('before querying observations or synop data') and notes the default behavior of returning all stations sorted by proximity. However, it does not explicitly mention alternative tools (e.g., meteostat.stations.nearby) or when not to use this tool, leaving some selection ambiguity.

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