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

Annotations already declare a read-only, idempotent, closed-world read. The description adds genuine semantics beyond them: that unpaid sales are excluded from totals, and that per-marketplace data availability differs (ML via KPI, Amazon absent), which an agent could not infer from the annotations.

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?

A single dense but front-loaded sentence that puts the main categories first and the marketplace caveats last; every clause carries information. It is slightly compressed but has no filler.

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 usefully states what comes back (per-marketplace breakdown, cancellation rate, totals) and covers the parameter contract via the schema. Only the alternative-tool routing is missing for full completeness.

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 each of the three date parameters is described in the schema, so the description needn't restate them. It adds no extra meaning about the days/start/end interplay, leaving it at the baseline.

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 specific verbs and resources: pending/unpaid Shopee sales, cancelled sales, broken out by marketplace, with cancellation rate and totals. This clearly distinguishes it from generic siblings such as painel_get_status_breakdown or painel_get_sales_summary.

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 clear scope plus exclusion rules — unpaid items sit outside totals, Mercado Livre enters only via the daily não-efetivadas KPI, Amazon has no status data and is excluded. It stops short of naming which sibling to use instead when the agent wants a broader status view.

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