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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds real domain semantics beyond that: funding is a fraction per hour with a worked conversion example and a sign convention (positive means longs pay shorts), plus the fact that a reading timestamp is returned. It doesn't discuss data freshness or failure behavior for unknown markets, which keeps it short of a 5.

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-loads the returned data, then units and sign convention, then routing to alternatives. Every clause carries information; no filler or restatement of the title.

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 an output schema and read-only annotations, the description supplies the remaining needed context: what is returned, units and sign convention for funding, and when to prefer siblings. Nothing an agent needs to 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?

Schema coverage is 100% and the schema description already enumerates accepted market formats (BTC-PERP, xyz:NVDA-PERP, HYPE/USDC, BTC, @107). The description only reinforces the single-market scope ('one Hyperliquid perp'), adding little syntax or validation detail beyond the schema, 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 set of resources (latest mark price, oracle price, hourly funding rate, reading time) for a scoped unit (one Hyperliquid perp). An agent can distinguish it from get_price and get_funding_rates without opening any 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 trigger ('when you need the oracle price or funding next to the mark, for example for basis or premium') and names three alternatives with the condition that selects each: get_price for price only, get_funding_rates for history, get_markets_snapshot for many markets.

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