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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description usefully adds that it is free, that hours are UTC, and that the spread is a live snapshot rather than historical. It says nothing about latency, rate limits, or how much data comes back, which is the remaining gap.

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?

A single front-loaded sentence opening with 'Free.' and then listing the payload contents; nothing is wasted. The enumeration is dense but each item is a real output, not filler.

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 correctly carries the burden of describing the return content — hourly volume extremes, per-hour volatility, weekend/weekday split, and live spread — which is exactly what an agent needs to decide relevance. Minor omissions are return shape and pagination.

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% with only two parameters, both documented in the schema including the 3–30 range and default of 14 for days. The description adds no syntax or format detail beyond confirming the UTC-hour interpretation, so the schema does the heavy lifting.

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 (a Hyperliquid market) and enumerates the distinct outputs — hourly trade intensity, volatility by hour, weekend vs weekday volume, current spread — which lets an agent distinguish it from siblings like weekend_gap and crypto_positioning. It does not explicitly name a sibling, so it falls short of a 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 description never states when to pick this tool over alternatives. 'Free' hints at a cost dimension but gives no condition, prerequisite, or exclusion, and the adjacent weekend_gap / crypto_positioning tools are not referenced.

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