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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so safety is covered. The description adds genuinely new behavioral context absent from structured fields: the fixed liquidity and price floors that define the result set. It does not discuss result ordering or pagination, but the output schema exists to cover returns.

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, front-loaded with the use condition, with the qualifier threshold embedded inline. Dense but every clause carries selection-relevant information; 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?

For a filtered-list tool with an output schema and full safety annotations, the description supplies the essential use case, the liquidity criteria, and the sibling routing. The one gap is the undocumented 'limit' parameter, which neither the schema nor the description explains.

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?

Only 50% of the schema carries descriptions: the 'game' enum is documented, but 'limit' (default 15, max 50) has no description anywhere. The description's thresholds ($5, 25 sales) are fixed filters rather than parameters, so they add scope context but not parameter meaning. A baseline 3 fits when the schema does half the work.

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 ('recent gainers' / cards rising in price) with precise scope conditions: at least 25 recorded sales/year and a raw price of at least $5, across all games and sports. It explicitly contrasts itself with the sibling trending_cards, so an agent can distinguish the two without opening schemas.

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?

Gives explicit when ('flipping or selling decisions'), an alternative plus its selection criterion ('Better than trending_cards'), and an explicit exclusion ('Do not use for a single named card'). This is the full when/when-not/alternative triad.

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