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

Adds real behavioral context beyond the readOnly/openWorld annotations: it discloses what is returned (readings, funding APR, OI, volume), and a billing carve-out ("Not charged when OI history is shorter than a window or Solana spot is down") that no annotation could convey. The injection warning about names/symbols is a valuable safety disclosure. Missing only rate limits and per-call cost mechanics.

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?

Three front-loaded sentences with no filler: capability first, then output shape, then the cost exception and injection caveat. Dense but each clause carries information an agent needs; the metric list is slightly redundant with the schema.

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?

Given an output schema exists and schema coverage is 100%, the description covers the remaining gaps an agent needs: screening semantics, output contents, billing exceptions, and untrusted-content handling. Nothing material is missing for correct invocation.

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 description coverage is 100%, so the enum values, defaults, limits, and the basis ticker list are already documented in the schema. The description restates the metric families and windows but adds little syntax or format detail beyond what's structured. Baseline 3 is correct.

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 verb and resource ("Scan Hyperliquid perps for markets") plus the exact screening shape: 1-3 AND-ed conditions across funding APR, OI change, and basis. The composite-screener framing distinguishes it from single-metric siblings like cashboard_funding_extremes and cashboard_oi_movers.

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 description implies when this tool applies (multi-condition screening) and encodes scope restrictions (basis is Solana-asset-only, OI windows are 15m/1h/4h), but it never names an alternative or says when to prefer cashboard_funding_extremes / cashboard_oi_movers instead. Selection guidance is inferable rather than stated.

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