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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety is covered. The description adds nothing further — no note on what the detail payload covers, whether localized by Lang/Country, or that data comes from the live storefront. With annotations carrying the profile, the description still contributes no behavioral context.

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 four-word phrase, front-loaded with zero waste. It is efficient, though arguably so terse it borders on under-specification rather than true conciseness.

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?

An output schema exists, so return values need no explanation in the description. However, for a lookup tool keyed on a required AppID, the description says nothing about accepting a package name or the localization effect of Country/Lang, leaving the definition minimally viable.

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% (Lang, AppID, Country all documented with formats and defaults), so the schema does the heavy lifting and a baseline 3 is appropriate. The description adds no extra meaning about how Lang/Country affect the returned details.

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?

'Google Play app details' names the resource (a Google Play app) and implies a detail-fetch, but uses no verb and does not distinguish itself from siblings like googleplay_search, googleplay_reviews, or googleplay_permissions. An agent can guess it retrieves one app's metadata, but it must infer 'fetch by package name' rather than being told.

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?

No when-to-use guidance, no mention of alternatives such as googleplay_search (discovery) versus this single-app lookup, and no prerequisites stated. Usage is only implied by the tool name and the required AppID param.

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