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

Annotations already declare readOnlyHint and openWorldHint, and the description adds useful context beyond them: the returned items are 'hint items with images and target urls', and the upstream keyword variant is gated (a real operational constraint that explains why this narrower tool exists). It doesn't discuss pagination or result-size limits, but nothing is contradicted.

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?

Three sentences, no waste, and the core purpose is front-loaded before the sibling routing and the parameter note. The gating explanation is compressed into a single clause rather than a paragraph.

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 single-optional-parameter read tool with an output schema, the description covers everything an agent needs: what it returns, when to use it, which siblings to prefer otherwise, and what region does. No missing decision-relevant information.

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 coverage is 100% and the parameter is already documented with its enum list and default. The description's region sentence ('region selects the storefront ... defaults to my') restates essentially the same information, adding only the mild framing of 'storefront' selection. Baseline 3 is appropriate when the schema carries the weight.

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 and resource: 'List the keyword-free promotional prefills on Shopee's search landing page for one storefront', and even names the return shape ('hint items with images and target urls'). An agent can immediately distinguish this from shopee_suggest and shopee_search_hints, which it explicitly positions as keyword-driven.

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?

Gives an explicit use case ('merchandising prompts shown before a search') plus explicit routing rules: 'the upstream keyword variant is gated, so use shopee_suggest or shopee_search_hints for keyword-driven suggestions.' Both the when and the when-not are covered with named alternatives.

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