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

With no annotations, the description carries the burden and does reasonably well: it discloses the pay-per-call model ($0.005 per call, x402, USDC on Base), the output content, and the neutrality/disclaimer. It omits behavior like data freshness, latency, or failure modes, but the cost and scope disclosures are substantive beyond the name.

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?

Front-loaded with the purpose and tight at three sentences, each carrying information (what it returns, what it is not, cost). The parameter list and market example add slight redundancy but nothing 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?

With no output schema, the description compensates by enumerating the return values (liquidation price, vol distance, slippage, funding, liquidity, flags) and the pricing of the call. Only minor operational details (data freshness, precision of the vol metric) are absent, so it is largely complete for a stateless calculation tool.

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 75% and the schema already documents coin examples, the side enum, integer leverage and the size_usd range. The description only restates the parameter names (and repeats the long|short enum), adding little semantic meaning beyond the structured fields, so the baseline 3 applies.

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 ('Pre-trade risk check for a Hyperliquid perp') and even scopes the supported markets (crypto and HIP-3 stock/index perps like xyz:NVDA). No sibling tool covers this, and the description makes the function distinguishable without opening the schema.

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?

'Pre-trade risk check' clearly implies the use context (run it before sizing/opening a position), and it clarifies it is a neutral calculation rather than advice. It does not explicitly name alternatives or exclusions (e.g., relative to arena_open_position), so it stops short of full when/when-not routing.

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