ETF业绩数据：获取ETF基金近1年、3年、今年、成立以来的业绩指标，包括：收益率、年化收益率、年化波动、夏普比率、最大回撤、年化超额、信息比率

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. While it mentions what data is retrieved, it doesn't describe behavioral traits such as whether this requires authentication, rate limits, error conditions, or the format/timing of the response. For a data retrieval tool with zero annotation coverage, this leaves significant gaps in understanding how the tool behaves operationally.

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 a single, dense sentence that efficiently lists the time periods and metrics. However, it's front-loaded with redundant information (repeats the title) and could be structured more clearly, such as by separating the action from the data details. While concise, it lacks optimal readability for quick scanning.

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 the tool's moderate complexity (retrieving multiple performance metrics), no annotations, and an output schema present (which likely covers return values), the description is minimally adequate. It specifies what data is fetched but omits operational context like prerequisites, limitations, or error handling. The output schema reduces the need to explain return values, but behavioral gaps remain.

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%, with the single parameter 'query' documented as 'ETF基金代码或ETF基金名称' (ETF fund code or ETF fund name). The description adds no additional parameter semantics beyond what the schema provides—it doesn't clarify format requirements, examples, or handling of ambiguous inputs. Baseline 3 is appropriate since the schema adequately covers the parameter.

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?

Tautological: description restates name/title.

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 provides no guidance on when to use this tool versus alternatives. With sibling tools like 'fundPerformance' (for general funds) and 'etfBasicInfo' (for basic ETF data), there's no indication of how this tool differs or when it should be preferred. The description merely restates what the tool does without contextual usage instructions.

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