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

With no annotations, the description covers more than the baseline: it discloses the 30-day window, the sort key, the returned fields (current price plus 30-day low), and, importantly, per-call billing of $0.05 USDC, which is essential context for an agent deciding whether to invoke the tool. It does not mention rate limits, but for a read-only ranking tool this is fairly complete.

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 front-loads the purpose, then gives one concrete example and the billing line. Every element is useful, and the example row output is especially helpful, though the sentence is dense.

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?

There is no output schema and no annotations, yet the description still states what is returned (card model, current price, 30-day low, change percentage) and the cost. For a single-parameter read tool, an agent has enough information to invoke it correctly.

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 0%, and the only parameter, `top`, has no description in the schema. The example `market_movers(top=3)` makes clear that `top` controls how many entries are returned, which resolves most of the ambiguity; the default of 5 is already in the 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 gives a specific verb and resource: rankings of GPU price changes over the last 30 days, sorted by interval change percentage, with both drops and rises. It is clearly distinct from gpu_price and gpu_history, although it does not explicitly state the difference.

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?

The example implies the tool is used to get the top-N movers, but the description never says when to choose it over gpu_price (a current price) or gpu_history (a single model's trend). It provides no explicit exclusions or routing guidance.

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