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

Annotations already cover the safety profile (readOnly, non-destructive, openWorld), so credit goes to what the description adds beyond them: a non-obvious ranking bias toward claimed-owner products and the dedup-on-pagination contract. It stops short of describing return shape or randomness guarantees, so not a 5.

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-loads the trigger condition in a bracketed 【何时用】 block, then ranking, then continuation in three tight sentences. Almost no waste, though the search comparison slightly overlaps the trigger clause.

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 zero-required-parameter, read-only feed tool with no output schema, the description supplies the discovery intent, tie-breaking rule, and pagination contract. Return fields are not described, but there is no output schema to lean on, which is the only material gap.

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% and both parameters are self-documented, including exclude's dedup purpose which the description merely restates. limit's default of 10 is only in the schema, not the description. Baseline 3 applies when the schema does the heavy lifting.

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+resource ('randomly draws published products') and adds a ranking rule (products with a claimed owner surface first). An agent can distinguish it from the many list_/search_ product siblings without opening the 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?

Explicitly names trigger utterances ('随便看看', '让我发现些有意思的'), names the alternative it beats ('比 search 更适合「我也不知道我想要什么」场景'), and gives the continuation condition (pass seen ids into exclude). When/when-not/alternative are all present.

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