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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the bar is lower, and the description adds genuinely new operational context: per-call cost of ¥0.3, billing only on success, and automatic refund on failure or empty results. That is exactly the kind of behavioral detail annotations cannot express. It stops short of describing pagination behavior or how an agent detects the end of the listing.

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?

Four short sentences, front-loaded with purpose, then return shape, then use case, then cost model. Every sentence carries information an agent would otherwise have to guess, and nothing is repeated from the schema or annotations.

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 read-only listing tool with no output schema, the description does the necessary work by naming the returned fields and disclosing the billing model. The remaining gap is pagination semantics: with page defaulting to 0 and no output schema, an agent has no stated way to know when the listing is exhausted.

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%, so shop_id, page, and _token are already documented in the schema, and the description adds no syntax, format, or defaulting detail beyond it. Baseline 3 applies when the schema carries the parameter burden.

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 specific verb and resource ("搜索抖音店铺商品") and scopes it to a single shop ("该店铺在售商品列表"), then enumerates the returned fields (商品ID、标题、价格与销量). This lets an agent distinguish it from keyword-level siblings such as douyin_product_keyword_search, though that differentiation is implied by "该店铺" rather than stated explicitly.

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 supplies use-case framing ("做竞品店铺盘点、在售结构分析时用"), which implies when the tool fits. It does not name alternatives (e.g. douyin_product_keyword_search for cross-shop keyword lookup, douyin_product_detail for single-item drill-down) or state when not to use it, so routing still requires inference.

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