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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), so the description's value-add is the behavioral constraint: it fetches every resort in the region and is capped at 40 resorts, which signals potential latency and truncation. It doesn't say what happens when the cap is exceeded (error vs. partial results), leaving one gap.

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 filler, with the resource and scope front-loaded and the 40-resort limitation placed last as a caveat. Every clause carries information the agent needs.

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?

No output schema exists, but the description conveys the return shape (open-lift totals plus each resort's count), so the agent knows what to expect. The only missing detail is the failure mode when a region exceeds 40 resorts, a minor but real gap for a tool whose stated limit is the key constraint.

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 coverage is 100% and the schema already documents 'Region tag, case-insensitive', so the baseline is 3. The description adds real value by giving concrete example tags ("Utah", "Dolomiti") and pointing to ski_list_regions as the authoritative source, which the schema does not.

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 aggregation verb and resource ('open-lift totals for a whole region') plus the per-resort breakdown, so the agent knows this is a regional rollup rather than a single-resort lookup like ski_get_resort_status. It also names ski_list_regions as the origin of the region tag, separating the two tools cleanly.

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 tells the agent exactly where to get a valid region value (a tag from ski_list_regions) and discloses the 40-resort cap that governs when this call is appropriate. It stops short of naming an alternative for large regions or when-not-to-use guidance, so not a 5.

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