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

Beyond the read-only annotations, the description discloses important behavior: an empty list is valid, stale inputs return 503 and are never billed, and each call costs 0.02 USDC via x402 on named chains. It also explains how events are labelled and that tiers are based on each coin's own history with printed sample size.

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?

The definition is dense but well front-loaded: the first sentence states when to use it, followed by return semantics, edge cases, billing, and failure behavior. Every sentence adds operational value, and there is no filler.

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 an output schema present and annotations covering safety traits, the description supplies the remaining critical context: what is returned, how anomaly tiers and event labels work, empty-result semantics, stale-data behavior, and payment requirements. Nothing essential for correct invocation 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?

There are zero input parameters, so the baseline is 4. The description does not need to explain parameter semantics, and the empty schema is consistent with a parameterless alert-fetching tool.

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?

The description names a specific resource and verb: it identifies unusually moved Hyperliquid perps and explains the exact signal basis, including price move windows, open-interest change, and coin-relative tails. It does not explicitly differentiate itself from nearby sibling tools such as get_anomaly_flag, get_top_movers, or get_oi_spike_scan, which keeps it from a 5.

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?

The opening "Use when an agent needs to know which Hyperliquid perps moved unusually" gives clear usage context. It does not state when not to use it or name alternative sibling tools, so it lacks the explicit routing guidance required for a 5.

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