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

With no annotations provided, the description carries the burden well: it discloses the sign convention (positive means longs pay shorts), the implicit ordering when symbols are omitted, and the different return semantics for HIP-3 coins. It does not discuss rate limiting, data freshness, or error behavior, which keeps it short of a 5 for a zero-annotation tool.

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?

Four short sentences, each carrying distinct information, with the core definition front-loaded before the symbol/no-symbol cases and the sibling pointer last. No filler or restated field names.

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 two-parameter read tool with no output schema and no annotations, the description covers what is returned (hourly and annualized rates, Binance/Bybit comparison, spread), how the default call behaves, and the special coin class. Nothing an agent needs to call this correctly is missing.

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 the baseline is 3, and the description earns above that by explaining what `symbols` actually changes — omitting it triggers a sorted core-coin listing, and HIP-3 prefixes are mandatory rather than optional. It adds no detail about `limit` beyond the schema, but the schema already handles that fully.

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 verb+resource (next funding rate per Hyperliquid perp) with precise scope: per-hour and annualized, benchmarked against Binance and Bybit with the gap included. That is enough to distinguish it from get_hyperliquid_market, get_hyperliquid_history, and rank_hyperliquid_markets without opening any schema.

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 branching conditions: symbol-less calls return core coins sorted by Hyperliquid rate size, while HIP-3 coins (xyz:, ...) require symbols and return the current hourly rate instead of the next predicted one. It also names the alternative for historical data (get_hyperliquid_history with includeFunding=true), which is exactly the routing an agent needs.

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