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

With no annotations, the description carries the full behavioral burden and does disclose non-obvious traits: per-coin omission of unreachable/non-listing venues, Hyperliquid always present, and an OI-screened set with excluded_thin_venues/oi_weighted flags so thin-book outliers are surfaced rather than silently dropped. It also states the per-call charge, but says nothing about freshness/latency, failure behavior, or what a $0.005 charge failing to settle looks like.

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 core purpose is front-loaded, but the body is one sprawling sentence built around an enormous parenthetical that reads as a raw field dump. Nearly every clause carries real information (there is no output schema), yet the lack of structure makes it hard to scan.

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 compensates by enumerating the returned fields (rates, OI in USD, arb verdict, funding_spread_bps, signals, timestamps, prices, volume) and the screening logic behind the verdict. What is missing is comparatively small: no hint of the paid-call failure mode and no routing to the cheaper preview sibling.

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 100% and the single `limit` parameter (default 20, max 100) is fully documented in the schema. The description adds no meaning about limit, and in fact never mentions it; baseline 3 applies when the schema does all the work.

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 names a specific resource (perpetual-futures funding rates) and a concrete scope (6 named venues, ranked by volume), so an agent knows exactly what data comes back. It never explicitly distinguishes itself from the sibling crypto_funding_preview, leaving that inference to the 'Live' wording and the stated cost.

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?

There is no when-to-use or when-not-to-use guidance; the only decision signal is the appended price line ($0.005 per call). The presence of crypto_funding_preview among siblings makes the missing routing rule ('use preview for a free snapshot') a real gap.

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