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

Goes well beyond the read-only annotations by disclosing error handling ('unknown coin answers 400 with the supported list and a stale source answers 503'), billing details ('Costs 0.004 USDC per call'), and payment rails. This is exactly the kind of operational context an agent needs before invoking a paid external API.

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 core purpose in the first clause and keeps every sentence informative. However, the long mid-sentence enumeration of return fields is dense and partly redundant given the output schema, which slightly hurts conciseness.

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 purpose, usage cadence, error semantics, billing, and supported assets; annotations handle safety and idempotency; and an output schema exists for return values. For a complex paid data-retrieval tool, the description provides everything an agent needs to call it correctly.

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?

The single 'coin' parameter is fully documented in the schema (100% coverage), and the description only reiterates the examples already present there. No additional syntax, format, or constraint information is added beyond what the schema provides, so the baseline 3 is appropriate.

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 ('Signal for one Hyperliquid perp') and enumerates the exact data returned, making the tool's purpose immediately clear. It distinguishes itself from broader siblings like get_signal_board by scoping everything to a single coin and adding forecast, heatmap, and whale details.

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 clear context ('for trading bots') and a concrete polling cadence ('Poll every 1-5 minutes'), which tells the agent when this tool is appropriate. It does not explicitly name alternative tools or state when not to use it, but the per-coin aggregation scope implies the intended use case.

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