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

Annotations already mark readOnlyHint=true, and the description reinforces that with 'Read-only — never uploads or pushes assets,' adding a concrete behavioral guarantee beyond the annotation. It also discloses the kinds of results returned (count, score, grade, levers), which is useful given there is no output schema.

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 description is short and front-loaded with the core purpose and result payload. Slight redundancy exists with 'Read-only' appearing twice, but the second mention adds the meaningful 'never uploads or pushes assets' clarification.

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?

For a simple read-only tool with three fully documented parameters, the description covers the key context: scope, safety, and result categories. The absence of an output schema is partially mitigated by listing count, score, grade, and levers, though exact return formatting is not specified.

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 the parameters are already well documented. The description does not add parameter-level detail, but none is needed for the baseline since the schema fully covers query, country, and bundleId.

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 clearly states what the tool does: it scores screenshots in the app's live store gallery and reports count, score, grade, and improvement levers. This is specific and differentiates it from siblings like keyword_gaps or audit_app, which cover different concerns.

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?

The description implies use when screenshot coverage analysis is needed and explicitly warns that it never uploads or pushes assets. However, it does not name alternatives or explain when to prefer this tool over the audit or preview siblings, leaving usage guidance mostly implicit.

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