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

With no annotations provided, the description carries the burden of explaining behavior. It does disclose the returned metrics and their trading relevance, but it does not mention read-only guarantees, data freshness, latency, rate limits, or any side effects. This is adequate but has clear gaps.

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 purpose is front-loaded and the usage-oriented sentence contributes real value. The phrase 'a trading agent actually uses' adds slight flavor but does not materially hurt. There is no redundant boilerplate.

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?

This is a relatively simple read tool and the description compensates somewhat for the missing output schema by listing the derived metrics. However, all three parameters are optional in the schema and the coin/symbol/depth relationship is left ambiguous, which is a real gap for an agent choosing arguments.

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%, so the baseline is 3. The description reinforces the notion of 'requested levels' for depth and 'one perpetual' for the instrument, but it does not clarify the relationship between coin and symbol, or specify depth formats, defaults, or valid values.

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 clearly identifies the resource as a Hyperliquid L2 order book for one perpetual and enumerates the derived microstructure fields returned. This distinguishes it from sibling hyperliquid tools like candles, funding, mids, and perps, though it lacks an explicit verb such as 'get' or 'fetch'.

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 final sentence provides a concrete decision context: use this tool to spot thin or lopsided books before sending an order. It gives clear context but does not name alternative tools or explicitly state when not to use it, so it stops short of a 5.

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