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

Beyond the readOnly/idempotent annotations, it discloses caching behaviour (answers served from own caches, each source named with its as_of), failure semantics (a stale source answers 503 and is never billed), and the billing model (0.01 USDC per call, x402, listed chains). These are exactly the operational traits an agent cannot infer from annotations.

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?

It is front-loaded with the resource and its ranking, then the per-coin columns, then operational terms, with no filler sentences. The inline flag formulas (crowded_long, squeeze_risk, liq_spike) are lengthy and arguably overlap with the output schema, which slightly dilutes 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?

With an output schema present, the description does not need to explain return values, and it covers the remaining agent-facing gaps: staleness handling, cost, payment rails, and cache provenance. Nothing needed to invoke this tool correctly 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 description coverage is 100%, so the schema already documents both parameters, and the description's restatement ('30 coins by default, up to 60, or the coins you list') adds no syntax or format detail. Baseline 3 applies because the schema does the heavy lifting.

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 verb and resource — a perp signal board table ranked by open interest in USD — and enumerates the exact columns returned. It is clearly distinguishable from siblings like get_perp, get_coin_signal and get_positioning, which serve narrower, single-metric purposes.

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?

It states an explicit operating context ('Poll every 1-5 minutes') and explains why this call replaces many narrower reads ('one call is the whole market structure'), which implicitly routes the agent away from per-coin siblings. It never names a specific alternative tool or a when-not condition, so it falls short of a 5.

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