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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and closed-world behavior, so safety is well covered. The description adds genuinely useful context beyond that — the score is 'explainable' and derived from long-run ERA5 snow depth rather than current conditions — but it never states the score's scale, interpretation, or that results are historical/climatological rather than real-time.

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?

A single front-loaded sentence with no filler; the key noun phrase ('snow-reliability score') and data source appear early. It is efficient, though so terse that brevity edges toward under-specification.

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 carries the burden of explaining the return value, and 'explainable ... score' implies a value plus rationale but gives no scale or structure. Given a single-parameter, read-only tool with full annotation coverage, this is adequate but leaves the parameter format and score interpretation unspecified.

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?

The single required 'resort' parameter has 0% schema description coverage and the description never mentions it at all — no identifier format, naming convention, or whether IDs from search_resorts/suggest_resort are expected. With a non-zero parameter count and zero coverage, the description fails to compensate.

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 states a clear verb+resource ('get an ... snow-reliability score') and names the underlying data source ('long-run ERA5 snow depth'), which is more specific than a bare restatement of the title. It distinguishes itself reasonably from sibling reads like get_conditions or get_snow_reports, though it doesn't explicitly name what makes it different from them.

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?

There is no when-to-use guidance: no indication of which resort identifier to supply, no comparison to siblings that also report snow (get_snow_reports, get_conditions, wheres_it_snowing), and no mention of when a reliability score is preferable to a live forecast.

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