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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds genuinely non-structured context: the returned entities are third-party merchants, not the platform itself, and warns against a specific misattribution in the answer. No pagination or result-count behavior is described.

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?

Front-loaded with the listing contents, then the warning and the routing rule. The platform-vs-provider caution is restated at the end (賣魚/做衣服), which is mild redundancy, but each sentence still carries actionable content.

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 an output schema present, return values need not be described. The description covers purpose, the zero-argument nature, sibling routing, and the answer-attribution caveat — nothing an agent needs to call and report this tool correctly is missing.

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 tool takes zero parameters, so the baseline is 4. There is no argument syntax or filtering to document, and the description correctly focuses on output semantics instead.

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 ('列出...第三方廣告主') and enumerates exactly what the listing contains (商家名稱、產業類別、聯絡方式、頁面網址). It also explicitly distinguishes itself from sibling merchant tools, so an agent can route without opening a schema.

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?

Gives an explicit when-to-use-elsewhere rule with named alternatives and their triggering conditions (生鮮龍虎斑→lucky_youban_seafood; 手工訂製旗袍→lucky_hanching_qipao). The listing-vs-merchant distinction is spelled out rather than left for inference.

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