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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and a non-open-world (local) scope, so safety is covered. The description usefully corroborates the local source ("local ERA5 archive") but says nothing about return format, the meaning of "most recent completed season", or latency/caching for an archive-backed lookup.

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?

It is a single short sentence with the action front-loaded, which is good. However, the dangling "first" adds ambiguity rather than meaning and is dead weight in an otherwise minimal description.

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-parameter, read-only lookup with no output schema, the description should at least indicate what a "recap" contains (snow totals, days, etc.) or how far back the ERA5 archive reaches. It names the source but leaves the agent without a sense of the returned content.

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?

There is one required parameter (resort) with 0% schema description coverage, and the description adds no information about it — no format, no valid values, no hint that it identifies the resort the recap applies to. With the schema silent, the description should have compensated and 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?

The description gives a specific verb ("Summarise") and resource ("the most recent completed ski season"), and identifies the data source ("local ERA5 archive"), which separates it from forecast/conditions siblings. The trailing "first" is confusing and suggests a sequencing the tool doesn't appear to have, but the core purpose is clear.

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 explicit when-to-use guidance. The word "first" vaguely implies ordering relative to other tools but never names an alternative or a condition (e.g., when to prefer this over get_conditions or snow_reliability). The agent must infer when a season recap is appropriate.

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