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

Goes well beyond the annotations: names the data source (Hyperliquid's public API), discloses pricing ($0.01/call via x402 USDC or card key, first 25 free, failed calls free), and explicitly warns that repeats are not free, which explains the non-idempotent cost model behind idempotentHint=false. It also confirms the call changes nothing, reinforcing readOnlyHint/destructiveHint.

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 the default behavior, then cost/auth, which matches how an agent decides and calls. Slightly over-stuffed in one paragraph, and 'Reads or computes only and changes nothing' partly restates the readOnly/destructive annotations, but no sentence is wasted overall.

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 carries the burden of describing return values and does so field by field. Combined with the single optional parameter and the disclosed default, an agent has everything needed to call it correctly and interpret the result.

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 single parameter is well documented there, so the baseline is 3. The description adds real meaning: it confirms the symbol format with examples (BTC, ETH, SOL, HYPE), specifies the default set is ranked by 24-hour volume (a detail the schema only calls 'most traded'), and gives a concrete call example.

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 ('Live Hyperliquid perpetual futures data for a coin') and enumerates the exact fields returned: mark/oracle/mid price, hourly funding rate and APR, premium, open interest in coins and USD, 24h volume and price change, max leverage. That field list makes it clearly separable from siblings like hyperliquid_prices, hyperliquid_candles, hyperliquid_orderbook and hyperliquid_funding_history 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 explicit use cases ('funding-rate checks, basis trades, derivatives dashboards and market context') and states the no-argument fallback behavior. It does not, however, name any sibling alternative or say when a different tool (e.g. hyperliquid_funding_history for historical funding, hyperliquid_orderbook for depth) would be the better pick.

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