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

Annotations already declare readOnlyHint=true, destructiveHint=false, openWorldHint=true and idempotentHint=false, and the description usefully explains the non-idempotency ('each call is charged, so repeats are not free') plus the data source (Hyperliquid's public API). That cost/rate context is genuine added value, but the description cannot itself explain why a read is non-idempotent beyond billing, and it adds little else over the annotation set for a pure read tool.

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 resource and payload, then limits, then usage, then cost — a sensible ordering with little filler. It is a single dense paragraph where the pricing and example clauses ('Example: coin=BTC') could be tightened, but no sentence is truly wasteful.

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?

Covers everything an agent needs with no output schema: what a bar contains, interval granularity, the 1-500 bar cap with default, ordering, source, cost/free tier, and confirmation of no side effects. Nothing material for a correct call 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%, so the baseline is 3; the description nevertheless adds the bar ordering ('newest last') and the 500-bar/50-default ceiling in the prose, both of which the schema does not state. Its interval list ('1m, 5m, 15m, 30m, 1h, 4h, 1d, 1w and more') is vaguer than the schema's exhaustive enumeration, which keeps it from a 5.

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?

Gives a specific resource (historical OHLCV candles for a Hyperliquid perpetual) and spells out the payload fields (open, high, low, close, volume in coins, trade count). It does not differentiate itself from sibling tools such as hyperliquid_indicators or hyperliquid_prices, so an agent must infer which one to use for computed indicators vs. raw bars.

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?

Names concrete use cases — charts, backtests, volatility and trend checks, context for a trading agent — which is a clear positive context. It stops short of explicit when-not guidance or naming an alternative tool (e.g. hyperliquid_indicators for derived metrics), so usage is contextual rather than fully directed.

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