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

Annotations already declare readOnlyHint=true/destructiveHint=false, so the safety profile is covered. The description adds genuinely non-obvious behavior: it is the 'cheapest-tier' variant, it draws on the same Hyperliquid data as its parent, and it is 'Paid in USDC on Base' — a payment/auth requirement the agent would otherwise not know. It stops short of stating rate limits, latency, or error behavior.

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?

Three short sentences, front-loaded with the identity of the tool, then the routing condition, then the data/payment context. No filler or repetition.

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?

An output schema exists, so return values need no explanation; the description still covers the differentiator (bp fields vs absolute prices), the data source, and the cost/payment model. Nothing an agent needs to select or invoke it correctly is missing.

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?

Single parameter with 100% schema description coverage ('Hyperliquid perpetual ticker, e.g. ETH or BTC'), so the schema fully documents it and the baseline of 3 applies. The description adds no format, casing, or validation detail beyond 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 resource (oracle-gap basis-point values) and its relationship to a named sibling: 'thin wrapper around market.oracle_gap'. It also enumerates the exact returned fields (mid_oracle_gap_bp/mark_oracle_gap_bp, elevated flag), so an agent can distinguish it from market.oracle_gap without opening either 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?

Gives an explicit selection condition ('use this when you only need mid_oracle_gap_bp/mark_oracle_gap_bp and the elevated flag') and an explicit exclusion ('not the absolute mid/mark/oracle prices'), which routes the agent to the parent tool market.oracle_gap for the full-price case.

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