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

With no annotations, the description carries the full burden, and it does disclose meaningful behavior: the estimate is derived mechanically from historical dividends, and the output is framed as a range rather than a point prediction. It also sets expectations that the result is not investment advice. It does not state permissions or return format, but for a read-only estimation tool this is solid disclosure.

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?

A single front-loaded sentence carries the core purpose, methodology and two metrics, followed by a short disclaimer. No padding, though the disclaimer sentence is marginal.

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?

With no output schema and no annotations, the description does describe what gets returned (dividend range plus estimated yield under two methodologies), which is the main thing an agent needs. Minor gaps remain on permissions and precise return structure, but it is largely complete for a single-optional-param read tool.

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% (the single 'code' param documents '不填回傳全部'), so the schema already does the work. The description adds nothing about the code parameter, making the baseline 3 correct.

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?

States a specific verb and resource: mechanically extrapolating a high-dividend ETF's 2027 dividend range and estimated yield from historical payouts. It goes beyond the name by naming the two yield methodologies (trailing 12-month sum vs latest-period annualized), which lets an agent distinguish it from the sibling get_etf_dividends, though it never routes explicitly against that sibling.

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?

There is no when-to-use guidance and no comparison to the alternative get_etf_dividends, which is the most likely source of confusion. The closing '不是投資建議' is a disclaimer, not usage guidance, so the agent must infer the use case entirely.

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