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

No annotations are present, so the description must convey behavioral traits. It does mention the PRO requirement and indicates that symbols are matched exactly ('代码原样匹配'). It also specifies date formats and returns a JSON array with listed fields. However, it does not disclose whether at least one parameter is required, how parameters interact, or any pagination/rate limits, leaving gaps in the behavioral picture.

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 well-structured, with a clear title, a brief note on subscription requirements, and separate Args and Returns sections. It avoids unnecessary detail and is easy to scan. The Args section repeats schema descriptions but does so succinctly, so the structure earns high marks.

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?

The tool has an output schema and 5 optional parameters. The description covers parameter formats and return fields, but does not explain whether a symbol is effectively required, how date ranges are interpreted, or what the numeric fields (mkv, amount, etc.) represent. It also offers no comparison with sibling tools, so the context is adequate but not complete for a fully informed choice.

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?

The input schema has 100% description coverage; every parameter includes a Chinese description that exactly mirrors the Args section in the tool description. The description adds no extra meaning beyond repeating the schema information, so the theoretical baseline of 3 applies. It includes one example (000001.SZ) which slightly aids understanding, but overall no new semantic value is added.

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 clearly states 'ETF 持仓明细' (ETF holdings details), specifying the resource and the type of data returned. The purpose is unambiguous and the parameter list supports it. However, it does not explicitly distinguish from sibling tools like tracking_indices or etf_daily, so it is not a perfect 5.

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 only usage guidance provided is the PRO subscription requirement and the 403 error for lower tiers. There is no information on when to prefer this tool over sibling alternatives, no exclusions, and no context on typical use cases. The agent is left to infer when 'portfolio' is appropriate.

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