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

Annotations already declare readOnlyHint=true and openWorldHint=false, and the description goes well beyond them: it discloses that bot traffic (link previews, mail scanners) is excluded but surfaced in totals.botScans, that `days` is capped by the plan's analytics history (range.maxDays), and that Free plans return only totals and top QR codes with insights.included=false and an upgradeUrl.

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 returned metrics are front-loaded in the first clause, followed by bot-handling and plan behavior. It is dense and somewhat run-on, but every clause carries operational information rather than filler.

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 and sparse parameter documentation, the description does the heavy lifting by describing the returned fields, the bot-exclusion rule, and degraded Free-plan output. The remaining gap is parameter interaction (qrId vs companyId) and whether `days` is relative to now.

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 only 25% (only includeBots is documented), so the description carries real weight — it supplies the default (30) and the plan-driven cap for `days`, and conveys that qrId/companyId narrow the scope to one QR or one company. It stops short of clarifying precedence or mutual exclusivity between qrId and companyId.

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 a specific verb+resource (scan analytics) and enumerates the exact outputs — totals, unique scans, daily series, top QR codes, geographic/OS/device/referrer breakdowns — so an agent can distinguish this aggregate view from raw-record siblings like scans_list or qrs_list without opening a schema.

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?

Scope selection (workspace, one company, one QR) is implied through the described outputs and parameters, and the plan-tier caveat is spelled out. However, it never states when to prefer this over scans_list for raw records, nor how qrId and companyId interact when both are supplied.

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