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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered. The description adds real behavioral context beyond that: the Partner Center daily sync and its one-to-two-day lag, plus the comparison-against-prior-period semantics, which materially affect how results should be interpreted.

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 metric list is front-loaded in a single dense sentence, followed by one short sentence on data provenance. It is efficient and free of filler, though the opening sentence is long enough that range/default details arrive late.

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 correctly carries the burden of describing the payload: downloads, installs, revenue, ratings, period-over-period change, and top markets. The only gap is that it doesn't state whether the default range applies when omitted, though that is covered in the schema.

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 both parameters are fully documented in the schema, including the enum values and default. The description restates the range options and default without adding syntax or behavior beyond what the schema provides, so the baseline of 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?

States a precise verb (downloads/installs/revenue/ratings for one app) and the exact resource scope, so an agent can immediately distinguish it from siblings like get_app_settings or list_reviews. The metric list and time-window framing leave no ambiguity about what is returned.

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?

Usage is implied by the metric list, but there is no explicit when-to-use guidance, no named alternative, and no exclusion cases (e.g., use list_apps first to obtain the id). The data-lag note hints at freshness limits but is not framed as guidance.

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