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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive, so the safety profile is covered. The description adds genuine context beyond that: the data is 'live', the response is ordered best-first, each level carries price/size/order-count, and '(api:read)' signals the required scope.

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 dense sentences with the purpose and return shape front-loaded; almost every clause carries information. It is slightly packed with parenthetical format detail, but nothing is wasted.

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?

For a single-parameter read tool with no output schema, the description covers purpose, return structure, ordering, and the full range of valid symbol inputs. An agent has everything needed to call it correctly.

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 carries the full burden and does so thoroughly: it explains the three accepted symbol forms (perp like BTC/HYPE, HIP-3 like xyz:TSLA, spot pair-id like @107), gives examples, and ties valid values to scan_markets. This meaningfully exceeds the raw regex pattern in the schema.

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 and resource ('The live Hyperliquid order book for one market') and immediately defines scope plus return contents (bids and asks, each level {px, sz, n}, best first). This is clearly distinguishable from siblings like get_prices, get_bars, and get_live_snapshot.

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?

Usage is implied rather than stated: an agent can infer this is the tool for depth/liquidity inspection, and the description usefully points at scan_markets as the source of valid symbols. But it never states when to prefer this over get_prices, get_bars, or get_live_snapshot, nor any exclusions.

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