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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower. The description adds genuinely useful non-annotation context: the exact cost (0.005 USDC per call) and the x402 payment rails (Solana, Base, Polygon, Arbitrum, Arc), plus the fixed liquidity-floor filter and the 5-item cap.

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 tight sentences, front-loaded with the when-to-use trigger and the returned payload; the cost and payment rails come last. Nothing is redundant and the size matches a zero-parameter, single-shot tool.

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?

An output schema exists, so the description need not detail the return shape, yet it still summarizes the payload usefully. Payment requirements are disclosed, which is essential for a paid endpoint. The one real gap is routing guidance against the other funding tools, which the description leaves unresolved.

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?

The tool takes no parameters, so the baseline is 4. The description's mention of an internal liquidity floor is context rather than a parameter, and there is no parameter surface that needs explaining.

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 and a precise scope: the 5 largest absolute annualised funding rates on Hyperliquid perps above a liquidity floor, with named fields (8h rate, open interest, 24h price move). However, it fails to differentiate itself from obvious siblings like get_funding_extremes, get_funding_radar and get_funding_rate, which sound like near-identical capabilities.

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?

"Use when an agent needs the most extreme funding rates right now" plus "One call, not a full screen" gives implied usage context. But with get_funding_extremes and get_funding_radar in the sibling list, the description never says when to pick this over them — a significant omission for a crowded funding-rate family.

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