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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), so the bar is lower. The description adds genuinely non-obvious behavioral facts: a $0.002 cost and payment instructions for the live x402 endpoint, plus explicit execution-risk warnings – none of which are inferable from structured fields.

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 sentences, front-loaded with the primary resource before the feature enumeration. Dense but nearly every clause maps to real output; it trends toward a feature dump rather than crisp prose but wastes little.

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 helpfully enumerates return contents (rates, venue intervals, annualized comparisons, provenance, risk warnings) and the payment flow. It is complete on the response side; the gap is undocumented parameters, which slightly undermines call correctness.

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 description coverage is 0%, so the description must carry parameter meaning, but it never explains sort, limit, or minOiUsd. Phrases like 'open interest filters' and 'annualized comparisons/spread signals' only faintly gesture at minOiUsd and the sort values without stating formats or defaults.

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?

Names a specific resource (perpetual-futures funding rates) with a concrete scope (Hyperliquid, Binance, Bybit) and enumerates the distinct outputs it produces. No sibling tool covers funding rates, so the resource is unambiguous.

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 description tells the agent what it will get (rates, annualized comparisons, spread/arbitrage signals) and implies the cross-venue comparison use case, but never states when to prefer it or what conditions precede a call. No exclusions or alternatives are offered, leaving usage to inference.

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