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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds some useful context by explaining the preferred-currency behavior and the changePct percentage convention matching get_card, but it does not describe return format or ordering in detail.

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?

The description is three sentences with the core behavior front-loaded, followed by pricing and percentage conventions. It is compact and contains no filler, though the first sentence somewhat restates the title and schema options.

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 market query with optional parameters and no output schema, the description covers the main behavior, time windows, change metrics, currency behavior, and percentage format. It is sufficient for an agent to call the tool correctly, though an explicit output shape would make it fully complete.

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 only 50%, and the description compensates by adding meaning beyond the schema: it clarifies that changePct is a percentage with an example and that prices use the user's preferred currency unless a source is given. Limit and window semantics remain mostly schema-only, but those are fairly self-explanatory enums.

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 clearly states that the tool returns the biggest price gainers and losers across the Gundam Card Game market, with explicit time windows and change metrics. This is specific enough to identify what the tool does and to distinguish it from collection-focused siblings such as my_collection or get_card.

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 guidance on when to use this tool versus alternatives like best_buys, price_list, or get_card, and no exclusions are given. The only usage cues are implicit in the market-wide scope, so an agent is left to infer the intended choice.

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