单品推广日报、分时及创意图日报（只读）

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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description reinforces the read-only nature. Valuable non-obvious behavior is added: platform-suppressed null metrics are not zero, creative hours are unsupported, and expectedMallId is mandatory for shop verification. This goes beyond what annotations alone provide.

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 one dense sentence, front-loaded with the core action and resource, followed by return contents and finally critical constraints. Every clause carries meaningful information with no wasted words.

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, the description still names the major return categories: dailyReport, 24-hour metrics, creative images, and daily metrics. It also covers key constraints and null semantics. It could mention error behavior or exact response fields, but for a read-only detail tool this is largely sufficient.

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 60%, so the description must partly compensate. It does add meaning to expectedMallId as a shop-verification parameter and ties adId to the target promotion, but it does not explain the date format or the shop/cdpUrl relationship beyond what the schema already provides.

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 the action: '按adId读取单个稳定成本推广的昨日/指定日数据' and enumerates what data is returned (dailyReport, 24-hour raw metrics, creative images, daily metrics). It does not explicitly name sibling alternatives, but the scope is specific enough to distinguish it from list-level or operations-level tools.

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?

It gives clear usage context: read one stable-cost promotion's data by adId, expectedMallId must verify shop, and only verified scenesMode=1 is supported. It also excludes creative-hour metrics, which helps the agent avoid expecting unsupported data. It does not point to an alternative tool for other cases, so it falls short of a 5.

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