Summarise app ratings

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

Annotations already declare this a safe read (readOnlyHint=true, destructiveHint=false), so the safety bar is met. The description adds two non-obvious behaviors the annotations do not cover: the 6-month maximum window and the API-client credential prerequisite. Rate limits and result volume remain 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 tight sentences, no filler, with the returned data shape and the window constraint front-loaded. Every clause carries information an agent needs.

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 compensates by naming the returned metrics (average, star histogram). Combined with the credential prerequisite and window cap, an agent has enough to call it correctly, though nothing explains pagination or aggregation granularity.

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%, so begin/end, site, platform, countries and appId are all documented in the schema; baseline is 3. The description's 'max 6 months' loosely constrains the begin/end pair but adds no format or default detail beyond what the schema already provides.

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 specific verb and resource ('Fetch ratings for an app') and enumerates the shape of the result (average, star histogram), which separates it from review-oriented siblings like agc_reviews_list. It does not name an alternative sibling explicitly, so it stops short of the top band.

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 the operative constraints (time window capped at 6 months, requires the API-client credential), which tells the agent when the tool is callable. It never says when to prefer this over agc_reviews_list, agc_review_insights, or agc_report_trend, so routing is left to inference.

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