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

The description discloses the return format (JSON array) and the exact fields returned, which provides some transparency beyond the schema. However, it does not explicitly state that the tool is read-only, nor describe behavior when filters are omitted or when no matches are found.

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 clear 'Args' and 'Returns' sections. The only minor redundancy is the repeated 'ETF' in the title and parenthetical.

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 description covers all parameters and return fields, which is useful for a query tool. However, it does not explain the default query behavior when all parameters are optional, nor how multiple filters interact, leaving some ambiguity for a user trying to construct a valid request.

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 already describes all five parameters with identical descriptions. The description's Args section simply repeats the schema content, adding no new semantic information. Since coverage is 100%, a baseline of 3 is appropriate.

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 identifies the tool as providing ETF basic information (ETF 基础信息) and lists filtering parameters, but lacks an explicit verb like 'query' or 'get', and does not distinguish it from sibling tools like 'stocks' or 'etf_daily'.

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 provided on when to use this tool instead of alternatives such as etf_daily or tracking_indices. The description only lists parameters without any context about use cases or exclusions.

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