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

Annotations cover read-only safety, but the description adds genuinely useful behavioral context: the data is live public HL API with a timestamp, responses return in seconds, results are constrained to $1M+ daily volume, and output is market data only. Most importantly it discloses that each call is paid (0.28 USDC on Base via x402) and pins the endpoint — a critical precondition an agent must know before invoking.

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 first sentence is an excellent, front-loaded summary. But the remainder is dominated by promotional and identity material — GHOST77 token address, ERC-8004 agent number, Virtuals ACP link, payout wallet, fee set-aside — that does not help an agent select or invoke the tool. Roughly two-thirds of the text does not earn its place in a tool definition.

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, the description carries the return-value burden, and it does reasonably well: it enumerates the sections returned (gainers, losers, volume leaders, funding extremes, breadth, BTC move) plus a timestamp. It does not describe response shape or field names, but for a read-only snapshot that is an acceptable gap.

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 100%, so both parameters (window enum, limit 3-25 with default 10) are already fully documented, establishing a baseline of 3. The description restates the window and limit range and gives a worked example payload, which helps but adds no semantics the schema lacks (e.g., what counts as a 'row' or whether limit applies per list independently).

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?

Opens with a concrete scope statement: 'top 24h gainers and losers, volume leaders and funding extremes across perps with $1M+ daily volume, plus breadth and the BTC move.' An agent can tell this is a Hyperliquid market-overview aggregator, distinct from siblings like hl_funding_snapshot or hl_smart_money. It stops short of naming those siblings as alternatives, so it lands at 4 rather than 5.

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 phrase 'at a glance' implies a survey/overview use case, and the $1M+ volume qualifier signals it is for liquid perps only. However, there is no explicit when-to-use vs when-not guidance and no routing to sibling tools such as hl_funding_snapshot for deeper funding detail. Usage is inferable but not stated.

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