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

Annotations already declare readOnlyHint=true, idempotentHint=true and openWorldHint=false, so safety is covered. Beyond that, the description discloses non-obvious behavior: results are compared against the preceding equivalent period, and breakdown dimensions are included alongside the headline counts. It omits scope (single page vs all pages) and result size/format, which matters since no output schema exists.

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?

Two sentences, front-loaded with the returned metrics and then the usage prompt. The metric enumeration is dense but earns its place; nothing is padded or repeated.

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, the description usefully enumerates the return contents, and the annotations carry the safety profile. The remaining gap is scope: nothing says whether stats are for the current page, a specified page, or the whole site, which an agent needs in order to invoke it correctly.

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 single parameter is fully documented in the schema (enum 7/30/90, default 30), so the baseline is 3. The description reinforces the window and adds that the comparison baseline is the preceding period of equal length, which is a genuine semantic addition but a small one.

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 states concretely what the tool returns — visits, page views, link clicks, plus top links, countries, referrers and devices — over explicit windows. It is not just a restatement of 'Page stats'. It does not, however, say whether the scope is one page or the whole account, nor distinguish it from siblings like get_history or grade_page.

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?

'Use it to suggest what to move up or change' implies a usage context (optimization decisions) but gives no when-not conditions and never names an alternative such as get_history or grade_page. The agent must infer the boundary from sibling names alone.

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