获取50ETF期权波动率指数(QVIX)

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It does disclose the output's meaning and historical range, which is valuable. However, it does not state whether this is a read-only operation (though fetching an index is inherently read-only), how QVIX is calculated, or whether the returned data is time series, latest value, or both. With no annotations, more behavioral detail would be expected for a higher score.

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 exceptionally concise: one sentence that packs the resource, alias, meaning, interpretation scale, and historical range. Every phrase adds information and there is no filler. The critical interpretation guidance is front-loaded.

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 simple single-parameter data retrieval tool, this is mostly complete. The output schema exists, so return format details are covered there. However, the description does not specify whether the returned data is historical series or just the latest value, nor does it mention data frequency/availability. Given the tool's simplicity and the output schema presence, the gaps are moderate—not severe but also not fully covered.

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 baseline is 3. The description adds context beyond the schema by explaining the index's meaning, but it does not add any new detail about the limit parameter's semantics beyond what the schema already provides (recent days, 0 returns all). The interpretation guidance is genuinely useful for value judgment, but it is not parameter-specific. Given full schema coverage and the small parameter set, a 4 is warranted for the extra interpretive value.

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 explicitly names the resource (50ETF期权波动率指数/QVIX), gives the relatable alias 中国版恐慌指数, and states the exact metric it reflects (market panic/greed). It also provides the practical interpretation scale (higher=more panic, historical range 15~35), which makes the tool's purpose immediately clear to an agent.

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 to use it—when QVIX/50ETF option volatility is needed—and the interpretation guidance is useful. However, it does not explicitly exclude alternatives or mention that sibling tools like fear_greed_index or market_broad_snapshot might serve broader market sentiment needs. The context is clear but there is no explicit when-to-use versus when-not-to-use statement.

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