list_weather_stations

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

No annotations are provided, so the description carries the burden. It mentions data source ('stations are loaded from the Icelandic Meteorological Office (api.vedur.is)'), which adds transparency. However, it does not disclose behavioral details such as whether results are cached, update frequency, rate limits, or that it is a read-only operation. The mention of 'Defaults to all' for limit is implied but not clearly stated as a default behavior. Overall adequate but lacks deeper behavioral context.

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?

Two sentences, zero wasted words. The first sentence tells exactly what the tool does and what it returns. The second sentence gives usage guidance. Every part earns its place. Well front-loaded.

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?

There is no output schema, so the description should explain the return structure. It lists return fields (IDs, names, types, coordinates) which is helpful. However, it does not explicitly state that the tool returns a list, mention any default ordering, or explain pagination behavior implied by the limit parameter. For a simple two-parameter tool, this is mostly complete but could add a note about sorting or the fact that 'all' is returned when limit is omitted.

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%—both parameters (limit and region) already have detailed descriptions including defaults and case-insensitivity. The description restates some of this (e.g., 'Defaults to all' for limit, 'Case-insensitive substring match' for region) but does not add new information beyond the schema. With full coverage, baseline 3 is appropriate; no extra value added.

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 lists weather stations in Iceland with specific fields (IDs, names, types, coordinates). It explicitly mentions two use cases: looking up station IDs for sibling tools (get_weather_now, get_weather_forecast) and helping users discover stations near a region. This distinguishes it from siblings and gives specific verb+resource 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 explicitly states when to use the tool: to look up station IDs for other tools or to discover stations near a region. It does not explicitly state when not to use it, but the context from sibling names (all weather-related tools) implies this is purely a lookup tool. The region filter hint ('e.g., 'north', 'capital', 'westfjords') provides additional guidance.

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