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

Annotations already establish readOnlyHint=true and openWorldHint=false, so safety is covered; the description's added value is the metric definition (typical asking price, then vs now) and the one-week window, which are genuinely beyond the annotations. It does not disclose ordering direction, whether results are capped by default, or what happens when a product has insufficient history.

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 with no boilerplate or redundancy, and the scope (weekly, all products) arrives before the metric clarification. Slightly dense with the parenthetical, but nothing is wasted.

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 simple read-only ranking tool with annotations covering safety and no output schema, the description conveys enough about what comes back (movers in both directions with before/after prices). The notable gap is the undocumented limit parameter and the unstated result ordering, which an agent would need to call it precisely.

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 optional parameter (limit, default 10, max 25) with 0% schema description coverage, and the description never mentions it. Because coverage is low, the description should have explained that limit controls how many moves are returned and that the maximum is 25, but it adds no meaning at all here.

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 resource and scope: 'biggest price moves over the last week across all tracked products', with the metric parenthetically defined as typical asking price then-vs-now and the direction covered ('falling and rising'). An agent can tell this is a ranked weekly-movers list and not a point lookup like get_price or a query like search_prices, though it never names those siblings explicitly.

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 implied by the phrasing: reach for this when you want the largest week-over-week moves rather than a specific product's price. There is no explicit when-to-use/when-not guidance and no pointer to alternatives such as deals or used_vs_new, which an agent must infer from sibling names alone.

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