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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds useful behavioral detail about returned fields and payload size, though it does not explain default date-range behavior or whether the result is a multi-row time series or a single summary object.

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 description is compact and front-loaded: what it does, what it returns, when it is useful, and how its payload compares. Every sentence contributes value and there is no redundant wording.

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 no output schema, the description reasonably explains the return signals and intended applications. A small ambiguity remains around whether 'per-day summary' is a time series or a snapshot, but the stated current values and year-high/low markers, combined with optional date bounds in the schema, are enough for an agent 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?

Schema description coverage is 100%, so ticker, start_date, and end_date are already fully documented. The description adds no parameter-specific meaning beyond the schema; it only describes the output and use cases, so the baseline 3 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?

The description opens with a specific verb and resource: 'Get per-day implied volatility and historical volatility summary for a ticker.' It names the returned fields (iv_current, hv_current, year-high/year-low markers) and contrasts with full chain data, which helps distinguish it from nearby options-history siblings.

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 gives clear use cases such as IV rank/percentile signals, vol regime detection, and time-series feature engineering. It also hints at an alternative by noting the payload is 'much smaller than full chain data,' but it does not explicitly name sibling tools or state when not to use this tool.

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