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

Annotations already cover the read-only/idempotent safety profile, and the description adds genuinely new context: per-call pricing ($0.002/call) and a precise definition of the population being measured (top 30-day-PnL accounts over the last N hours). It does not mention rate limits, caching, or pagination, which keeps it from a 5.

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 dense sentences with no filler. The return-shape listing leads the description rather than the purpose, which is slightly backwards for selection, but given the absence of an output schema the field enumeration earns its space.

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, describing flows[] and positioning[] fields is necessary and mostly done, and pricing is covered. But the description leaves the key 'n' parameter unexplained and its 'N hours' wording conflicts with the param name, so an agent cannot fully determine how to size the request.

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%: 'hours' documents 'Default 4', but 'n' (1-25) is undocumented in both schema and description. Worse, the description's phrase 'in the last N hours' uses 'N' for the time window while the schema's 'n' is a separate parameter, creating ambiguity about what 'n' actually controls.

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+resource ('see where top-PnL Hyperliquid traders are adding or cutting exposure across coins') and the opening 'Across coins' implicitly distinguishes it from the per-coin sibling hl_smart_coin. It never names that sibling outright, so the differentiation is left slightly implicit.

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 closing sentence gives a use case ('to see where top-PnL traders are adding or cutting exposure'), which is implied guidance. However, there is no explicit when-to-use/when-not statement and no reference to hl_smart_coin or hl_liquidations as alternatives for narrower or related queries.

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