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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so the safety profile is covered. The description adds behavior the annotations cannot express: values stay in each store's own currency with no conversion, and ad spend is deliberately excluded — both critical to interpreting results correctly. Return structure and pagination are still unstated.

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 sentences, zero filler: the first front-loads the returned metrics and the currency rule, the second handles the one exclusion with the alternative named. Every clause carries information an agent would otherwise have to guess.

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 what comes back, and it does so thoroughly — metric list plus per-store currency semantics. Read-only annotations cover the safety dimension. It could still say more about date-range defaults and multi-account behavior for a tool with four parameters, but the essentials are present.

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 75%, so the schema already documents the from/to date bounds, accountIds narrowing, userStatement and idempotencyKey. The description adds no parameter-level meaning — it never mentions the date range, per-account narrowing, or any defaults — so it neither compensates for the coverage gap nor improves on the schema. Baseline 3 applies.

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 names a specific resource (revenue for connected stores) and enumerates exactly which figures are returned: gross, refunded and net sales, order count, gross profit, break-even ROAS, customer value. It also explicitly contrasts with the sibling reporting_overview, so an agent can distinguish the two without opening either schema.

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 a clear negative routing rule — ad spend is not included here, use reporting_overview — which is exactly the kind of sibling disambiguation an agent needs. It stops short of stating when this tool is the right pick (e.g., per-store performance review vs. cross-tool comparison), so there is no positive when-to-use guidance.

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