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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds behavioral context beyond that, such as the number of years behind each fortnight so a thin sample is indicated, which informs the agent about data reliability. It also lists the specific data types returned, enriching the operational understanding without contradicting annotations.

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 moderately detailed but each sentence adds value: the first explains the core concept, the second details the data fields and quality, and the third covers the band filter. It is front-loaded with the primary purpose and avoids fluff. Slightly longer than necessary but not verbose enough to hinder readability.

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 read-only data retrieval tool with two parameters and no output schema, the description covers the essential aspects: what data is returned, how to filter by elevation band, and the data's historical depth. It does not describe the response format, but without an output schema that is expected. The description is sufficient for an agent to decide when to call this tool and what arguments to provide.

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 0%, so the description must compensate. It explicitly explains the 'band' parameter with its possible values (base/mid/summit) and that it is optional. The 'resort' parameter is not elaborated, but it is required and likely self-explanatory given the tool's domain. The description also clarifies the output content, which indirectly helps understand the parameters' purpose.

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's function: splitting ten winters into twelve fortnights per elevation band, with specific data fields (fresh snow, snow days, temperatures) and a filtering option for band. This is a specific verb-resource pair that distinguishes it from siblings like daily_snow or conditions, which focus on different time granularities. The mention of 'the granularity a trip is actually booked at' adds purpose context.

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 usage for trip planning by noting the granularity at which trips are booked, but it does not explicitly state when to use this tool versus alternatives like daily_snow or snow_forecast. It also does not provide exclusions or conditions under which another tool would be preferable. The band filtering is described, but no guidance on selecting this tool over others is given.

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