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

With no annotations, the description carries the full burden. It does disclose that results include expiration dates and that data is subject to official announcements, which adds useful context. However, it does not cover return format, freshness, or limitations beyond that disclaimer.

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 a single, front-loaded sentence. The leading bracketed tags '［台彩 發票 油價對獎］' add some noise and are not clearly explained, but the rest is efficient and to the point.

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 simple, parameterless retrieval tool with no output schema or annotations, the description adequately says what content is returned. It could be more complete by specifying the response structure or data freshness, but no critical information is missing for an agent to call it correctly.

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 has zero parameters and schema description coverage is 100%, so the baseline is 4. The description adds no parameter information, which is appropriate since there are no parameters.

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 states a clear resource: current fuel discounts and credit card rebates for Taiwanese gas station brands, with expiration dates. It distinguishes itself from 'get_fuel_prices' by focusing on promotions and rebates rather than prices, but does not explicitly name the sibling or contrast with it.

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 explicit when-to-use or when-not-to-use guidance is provided. The description only describes the content ('以官方公告為準') and does not indicate when an agent should call this tool versus alternatives like life__get_fuel_prices or shop__list_chain_promos.

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