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

Annotations already declare readOnlyHint, idempotentHint, and non-destructive, so the safety profile is covered. The description adds the default date range and the POST-with-group_by implementation detail, which is useful context, but doesn't disclose pagination behavior or return shape beyond what the output schema covers.

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?

Three short sentences, front-loaded with the core purpose, followed by the mechanism and the scope-specific requirement. No filler text.

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?

Given the read-only annotations and the presence of an output schema, the description covers what an agent needs: grouped-by-country output, default range, and scope-specific parameter requirements. It could mention pagination defaults or how scope affects which IDs are required, but is largely complete.

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 schema already documents all seven parameters including enum values and REQUIRED conditions. The description only confirms the idqrcode requirement for scope=qrcode, adding little beyond the schema's baseline.

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 (Fetch) and resource (scan counts grouped by country), and names the three scopes. It is clearly distinguishable from siblings like get_scans_by_device or get_scans_by_region by the grouping dimension.

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 explains the scoping requirement ('For scope=qrcode only idqrcode is required') and indicates the default range, giving clear context for use. It doesn't explicitly name alternatives like get_scans_by_date or get_total_scans, so no full when-not guidance.

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