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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds context about the promotion types and the 'current' temporal scope, which is useful. However, it does not disclose any additional behavioral aspects like pagination, rate limits, or the meaning of the /offers page reference.

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?

The description is short and front-loads the core purpose in the first sentence. The second sentence ('Also points at the /offers page.') is vague and adds little value, but overall the description is efficient and free of fluff.

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?

The tool is simple (2 params, both described, no output schema). The description covers the main function and grouping, but it does not clarify the return format, whether results are paginated, or the meaning of the /offers page reference. Given the lack of an output schema, a bit more detail on the expected result would be beneficial.

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% for both parameters, so the baseline is 3. The description adds minimal value beyond the schema: it repeats the grouping capability but provides no extra meaning for locale or group_by. It does not compensate for any gaps because there are none.

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 ('lists') with a clear resource ('current storefront promotions') and specifies the types (percentage/fixed discounts and free gifts) and an optional grouping by brand or category. It distinguishes from siblings like get_cart_promotions and get_product_promotions by scoping to storefront-level offers, so an agent can tell it apart without opening schemas.

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?

The description gives no explicit guidance on when to use this tool versus the many sibling tools (e.g., get_cart_promotions, get_product_promotions). The scope is implied by 'storefront promotions', but there is no mention of exclusions or alternatives, leaving the agent to infer the selection criteria.

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