get_etf_regular_investment_ranking

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly explains the data scope (top 10), the response structure, and possible error reasons, which is strong for a read-only ranking tool. It does not explicitly state 'read-only', but the nature of a get operation is clear and it adds meaningful context beyond the schema.

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 well-structured with clear sections for Args, Returns, and Raises, and it front-loads the purpose. It is somewhat verbose with the full return field list, but since there is no output schema, this information is necessary and earns its place.

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 no-parameter query tool with no annotations and no output schema, the description is remarkably complete: it explains the purpose, usage example, return fields, and error conditions. An agent has everything it needs to invoke the tool correctly and interpret the result.

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?

This tool has zero parameters, and the description explicitly confirms '無參數' along with an invocation example. The baseline for zero parameters is 4, and the description fully compensates by removing any ambiguity about arguments.

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 a specific verb ('取得' / get) and resource ('ETF定期定額排名資訊'), and explains that it returns a ranking of regular ETF investment by investor count. It distinguishes itself from sibling tools by naming the exact data type and top-10 scope, so an agent can identify its unique purpose.

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 a general use case ('可作為ETF投資參考指標') and a usage example, but it does not explicitly state when to use this tool versus alternatives or when not to use it. The usage context is implied rather than explicitly contrasted with sibling tools.

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