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

Annotations already cover the safety profile (readOnlyHint, openWorldHint), but the description adds genuinely non-obvious behavior: missing modules come back as empty lists rather than placeholders, and region defaults to my. It stops short of noting freshness/caching or per-region availability limits, which would be the remaining useful context.

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 front-loaded sentences, each with a distinct job: what it returns, when to pick it, and the region/empty-list behavior. The only waste is re-listing the eleven region codes already present in the schema.

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?

An output schema exists, so return shape need not be described, and the prose still names every module the caller will receive. With one optional parameter and read-only annotations, nothing an agent needs to invoke it correctly is missing.

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 description largely repeats the schema (region enumeration and my default) rather than adding syntax or edge cases. 'region selects the storefront' frames intent slightly, but there is no enum constraint in the schema and the description does not say how invalid regions are handled. Baseline 3 is appropriate.

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 (Get) and resource (one Shopee storefront's normalized home feed) and enumerates the exact modules returned: banners, category squares, campaign modules, flash-sale cards, search prefills, live sessions. This is distinguishable from every sibling at a glance.

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 selection rule: use it for the whole above-the-fold snapshot, and prefer shopee_banners, shopee_home_categories, or shopee_flash_sale when only a single module is needed. Both the when-to-use and the named alternatives are spelled out.

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