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

Annotations already convey readOnly/no-destructive, so the bar is lower. The description adds genuinely useful behavior beyond the annotations: the auth requirement ('Needs the user's Cotlet API key with access to this app') and the unit convention ('Earnings are in US cents'). It does not, however, note any rate limits or result caps.

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 first two sentences are near-verbatim duplicates, both listing 'earnings, units sold, carts, unique buyers, views and conversions.' The metrics list is front-loaded, but the redundancy wastes space and hurts structure.

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?

With no output schema, the description carries the burden of describing returns, and it does so by enumerating all metrics. It is complete for calling the tool correctly, missing only a note on the ordering/granularity of the period semantics.

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%, so the baseline is 3, but the description earns above baseline by explaining the intent of buyer_type and product_ids (compare cohorts, scope to part of the store) and clarifying the earnings unit, which the schema does not state.

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?

Names a specific verb (get) and resource (store stats / Seller Dashboard totals) and enumerates the exact metrics returned, so an agent knows precisely what it does. It does not, however, explicitly distinguish itself from the sibling get_product_stats, leaving that boundary to inference.

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?

It gives usage hints for two parameters ('Set buyer_type to compare first-time and repeat buyers, or product_ids to look at part of the store'), which is a form of context. But there is no explicit when-to-use-this-vs-alternatives guidance (e.g., get_product_stats or list_sales) nor any stated prerequisites for the period.

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