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

Annotations already declare this as a safe, read-only, idempotent operation. The description adds meaningful behavioral context beyond that: data is only available from the day history was switched on, it is kept beyond Google's 16-month retention, and alerts cover the last 30 days. It does not mention pagination or response format, but for a read-only aggregate history tool the added scope and retention details are substantive.

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 description is front-loaded with the resource and its contents, then moves to usage guidance and alternatives. The long enumerated list is dense but each item earns its place by specifying exactly what data is returned, and the final sentence cleanly closes with the alternative tools.

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 there is no output schema, the description fully carries the burden of explaining what the tool returns: a detailed list of metrics and alerts, plus temporal coverage constraints. Combined with the annotations and complete schema coverage, an agent has everything needed to call the tool 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?

Schema description coverage is 100%, so the parameters (days, site, group) are already fully documented in the input schema. The description does not add syntax, format, or default details beyond the schema, so the baseline of 3 is appropriate.

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 a specific resource (day-by-day stored SEO data) and enumerates its content (clicks, impressions, position, sessions, key events, revenue, vitals, index status, alerts). It also explicitly distinguishes itself from the gsc_ and ga4_ tools, which provide detail by page or query, so an agent can route correctly without opening sibling schemas.

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?

It gives direct usage guidance: 'Use it for trends and for "what changed and when"; use the gsc_ and ga4_ tools for detail by page or query.' This names both the intended use and the alternative tools, leaving no ambiguity about when to select this tool over siblings.

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