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

With no annotations, the description carries the behavioral transparency burden. It discloses output fields and the trade_date exclusivity rule, which is useful. However, it does not explain what happens when symbol is omitted, whether date ranges are limited, or what the adj_factor values represent, leaving meaningful behavioral ambiguity.

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, with a clear Args/Returns structure and no filler prose. The opening 'ETF 复权因子（ETF）' is slightly redundant, but overall every line is purposeful and appropriately sized.

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?

An output schema exists, so the description does not need to fully explain return values, and it does cover parameter formats and the exclusivity constraint. However, with all parameters optional, it leaves open questions about required inputs, default date ranges, and query limits, which are important for a financial data endpoint.

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%, and the description's Args section largely repeats the schema's parameter descriptions. It adds no new semantics beyond what the schema already states, so the baseline of 3 applies. The 'with start/end mutually exclusive' detail is already present in the schema too.

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 identifies the specific resource (ETF adjustment factor) and lists the output fields, making its purpose clear. It does not use an explicit verb like 'retrieve', but the Args/Returns structure implies a data-fetching tool. The mention of 'ETF/板块/外汇/港股等' helps distinguish it from general stock adjustment factor tools, though it does not explicitly name sibling alternatives.

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?

No guidance is given for when to choose this tool over alternatives such as adj_factor or etf_daily. The only usage-related note is that trade_date is mutually exclusive with start_date/end_date, which is a parameter constraint, not tool-selection guidance. This leaves the agent to infer applicability from the name and sibling list.

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