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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so safety is covered structurally. The description adds value beyond that by fixing unit conventions (in for snowfall, F for temperature) and naming return metadata (canonicalUrl, observedAt), though it says nothing about data freshness, aggregation across upstream sources, or behavior when a field is unavailable.

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, front-loaded with the full resource list before the disambiguation clause; nothing is padded or redundant. The first sentence is a dense comma-run of five data categories, which is efficient but slightly harder to scan than a short structured list would be.

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 single-required-parameter read tool with full schema coverage and annotations covering the safety profile, the description supplies what an agent still needs: scope, unit conventions, and two returned fields. Remaining gaps are minor — no indication of staleness thresholds or partial-data behavior — and there is no output schema to explain.

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%, so both the resort identifier and the lang enum are already documented in the schema, including the en/zh values and default. The description mentions neither parameter and adds no meaning about accepted resort forms or language fallback behavior, so the baseline 3 applies.

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 specific verb (Get) and enumerates the exact resources returned: base depth, recent snowfall observations, live lift/trail status, JMA AMeDAS station snow depth, and a compact avalanche/chain-control summary. It scopes to 'one ski resort' and names the sibling it is not (get_forecast), so an agent can distinguish it without opening a 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?

It gives one explicit routing rule: use get_forecast instead for upcoming snowfall predictions, which resolves the most likely confusion. It does not address the overlap with siblings like get_avalanche_danger and get_road_conditions, even though this tool returns an abbreviated avalanche and chain-control summary that those dedicated tools presumably cover in depth.

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