volatility

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

Annotations already declare read-only/idempotent/non-destructive, so the description's biggest value-add is the pricing and failure semantics: x402 (USDC on Base) or free with WICKEDAPI_API_KEY, and that an HTTP 402 carries a decoded price in payment_required which is a quote, not a failure. That is non-obvious behavior an agent cannot infer from structured fields and prevents a misdiagnosed error.

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?

Content is dense and every block earns its place (definition, example, usage/exclusion, payment behavior). Minor deduction: the example path is placed before the use-case guidance, so the routing information an agent most needs is not the first thing it reads.

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?

For a one-optional-param read tool with annotations covering the safety profile and no output schema, this covers purpose, currency scope, the ATR boundary, and payment/error behavior. It stops short of describing the shape of the returned values (units, whether realized vol is a window series or a scalar), which would fully close the gap left by the absent output schema.

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% and the single `currency` parameter is already documented in-schema as "BTC (default) or ETH". The description's example (`?currency=BTC`) and the repeated BTC-or-ETH scope add only marginal value beyond the schema, so the 3 baseline applies.

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+resource: Deribit DVOL implied-vol index (30d forward) plus latest realized volatility, limited to BTC or ETH. The trailing clause explicitly names the sibling `atr` as the tool for ATR-style sizing, so an agent can distinguish this from the nearest alternative without opening the schema.

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 an explicit when-to-use ("Use when you want Deribit implied volatility (DVOL) next to realized volatility for BTC or ETH") and an explicit when-not ("Not for other assets or ATR-style sizing (use atr)"). The alternative and the selecting condition are both named.

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