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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds real value beyond that by disclosing how to interpret the empty-result case as a capability gate. It does not discuss auth requirements or result shape, but that is a minor gap given the annotation coverage.

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?

Two tight sentences with no filler; the core purpose is front-loaded and the empty-list caveat follows naturally.

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 one-parameter read-only list tool with an output schema, the description covers purpose and result interpretation well. The only omission is any semantic hint about advertiser_id, which is partly mitigated by the output schema carrying the return contract.

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?

The single parameter advertiser_id has 0% schema description coverage and is never mentioned in the description. The phrase 'linked to the ad account' only loosely implies the parameter's meaning, so the description fails to compensate for the schema gap.

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 (Lists) and a specific resource (TikTok Shop stores linked to the ad account), then clarifies what those stores exist for (GMV Max campaigns run against them). No sibling tool covers TikTok Shop stores, so confusion risk is low and the scope is unambiguous.

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?

Provides useful decision context by explaining that an empty list means GMV Max is unavailable for the account, effectively telling the agent this is a prerequisite/availability check. It does not name an explicit alternative or an exclusion case, so it stops short of a full when/when-not statement.

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