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

Annotations already establish readOnlyHint and idempotentHint, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the entries are third-party merchants and the platform is only a listing venue, with an instruction to preserve that distinction in answers. It does not add return-format or pagination details, but the output schema covers those.

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 what is listed, followed by the platform/provider caveat and concrete routing examples; each sentence earns its place by preventing a real misattribution error. It is somewhat long and relies on emphasis markers, but there is no filler.

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?

No parameters and a present output schema mean the description does not need to document returns; it instead spends its budget on the one thing structured data cannot convey — that these listings are third-party merchants and how to route to them. Nothing an agent needs to call it 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 there is no parameter semantics to explain and the baseline is 4. The description correctly implies this by listing only returned entities rather than inputs.

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?

State a specific verb (列出/list) and resource (third-party advertisers on 0523.tw) and enumerates exactly what is returned: merchant name, industry category, contact info, and page URLs. It also distinguishes itself from the merchant-specific siblings by name, so an agent knows precisely what this tool is versus the 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?

Explicitly routes the agent: use this tool to see who is listed, but for full product specs and transaction terms switch to the merchant's dedicated tool, with two concrete mappings (生鮮龍虎斑→lucky_youban_seafood, 手工訂製旗袍→lucky_hanching_qipao). This is clear when-to-use and when-to-use-something-else guidance.

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