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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context by naming the returned counters and the 7-day measurement window, which the annotations do not convey; it stops short of stating scope (workspace-wide vs. per-campaign) or how 'active' is defined.

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 front-loaded sentence with no filler, no restatement of the title, and no redundancy. Every clause carries information the agent cannot get from the schema or annotations.

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 no parameters, the description is the only source of return-value information, and it only partially delivers: it lists the counters but not their types, whether they are nested per-campaign or a flat workspace total, or the time basis for 'total' and 'active'. Adequate for a simple counter call, but not fully 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?

The tool takes zero parameters, so there is nothing for the description to disambiguate at the input level; the baseline for a parameterless tool applies. The description instead spends its words on output semantics, which is the right allocation here.

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 (web-push subscription counters) and the specific metrics returned (total, active, new/unsubscribed in the last 7 days), making it distinguishable from analytics-style siblings. It is slightly weakened by the ambiguous slash construction 'new / unsubscribed in the last 7 days', which leaves it unclear whether the 7-day window applies to both metrics or only one.

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?

There is no explicit guidance on when to use this versus get_push_analytics, get_pwa_retention, or list_push_mailings, all of which live in the same push-domain cluster. An agent must infer from the word 'overview' that this is the lightweight summary call, with no stated exclusions or alternatives.

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