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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and a closed-world scope, so the safety profile is fully covered and the description can't add much there. What it does add — the returned shape (slug plus display name) — is genuinely useful because no output schema exists. It says nothing about ordering, count, pagination, or whether regions with no resorts appear, which keeps it at an adequate-but-thin 3.

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?

One sentence, front-loaded with the verb and resource, with the return fields appended as useful detail. Nothing is wasted and nothing is buried.

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 parameterless read-only catalog tool, the description covers the essential facts: what is listed and what each entry contains. Minor gaps (ordering, whether the list is exhaustive or filtered by tracked coverage, size) remain, but an agent can call this correctly with what is given.

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 tool takes zero parameters, which is the stated baseline of 4; there is no parameter semantics for the description to clarify or for the schema to omit.

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?

States a specific verb and resource ('List tracked ski regions') and even names the returned fields, so the agent knows this is a catalog enumeration tool rather than a data-fetch sibling. It stops short of a 5 because it never contrasts itself with the many data-retrieval siblings (get_region_snow, get_state_snow, search_resorts), leaving the agent to infer that this is the discovery/ID-resolution step.

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 prerequisite, and no reference to any alternative. An agent is not told that this is the natural first call to resolve a region slug before calling get_region_snow, nor when it should prefer search_resorts instead.

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