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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, so the safety profile is covered. The description adds real behavioral value by spelling out exactly what is returned (aggregate stats, example sales, and a link to the full list), which is the main thing an agent needs to decide whether to call it.

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 that names the resource first, then the metrics payload, then the return link. Dense but every clause maps to a distinct output the caller would care about; no filler.

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 return-value burden and does so explicitly by listing the aggregated statistics and the link to the full sales list. Parameter behavior is largely left to the well-covered schema, which is acceptable at 75% coverage.

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 75% and the schema already documents query phrasing, the 90-day default window, the country enum with guidance, and condition. The description adds only the 'one country' framing and no detail on the days window or condition, so it sits at the baseline for a well-documented schema.

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 names a specific resource (confirmed Vinted sold prices for an item in one country) and enumerates the computed outputs (sales count, median, p25-p75, days-to-sell, weekly sell-through, examples, link). The 'in one country' scoping implicitly separates it from vinted_compare_countries, though the sibling is never named.

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?

Usage is only implied: 'in one country' plus the schema note 'Pick the user's market; if unknown, FR has the most sales' hints at market selection, but the description never states when to choose this over vinted_compare_countries or what prerequisites exist. An agent must infer the routing decision.

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