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

Annotations already mark the tool read-only and non-destructive; the description adds useful behavioral constraints: the default 30-day window, the 92-day maximum, and the available grouping dimensions. It does not discuss pagination or rate limits, but for a read-only analytics call with an output schema this is adequate.

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 sentence packs the resource, window constraint, and grouping options with no filler. It is front-loaded with the core purpose and keeps the constraint detail compact.

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 an output schema present, return values do not need description. The definition covers the essential call semantics: one code, date window, and grouping. It could mention that only id is required, but the schema already marks it required, so nothing critical is missing.

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 50%, and the description compensates by explaining the window semantics (default 30 days, max 92) and listing the group enum values. It also clarifies that the id refers to a single code. It does not add detail about ISO date formatting, but the schema already provides that.

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 names the resource ('scan analytics for one code') and the scope ('over a window', 'grouped by...'), which clearly distinguishes it from siblings like get_qr_code or list_qr_codes. Although it lacks an explicit verb, the title 'Get scan statistics' supplies it, so an agent can tell what this tool does.

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 the tool is for retrieving per-code analytics over a date range, but it never states when to prefer it over alternatives or when not to use it. There is no explicit exclusion or pointer to sibling tools, so an agent must infer usage from the phrase 'one code'.

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