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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It accurately describes the period-over-period comparison and the metrics included, but it does not explicitly confirm this is a read-only reporting operation or explain how the comparison period is derived when custom dates are used.

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 concise sentences with no filler. The first states the metrics and comparison behavior; the second provides a clear usage cue. Every word earns its place.

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?

For a tool with no output schema, the description does list the returned metrics, which helps. However, it leaves some ambiguity about how the previous comparison period is computed when start_date overrides days, and it does not describe the result shape or edge cases like empty periods.

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 are already fully documented. The description adds conceptual context about periods and comparison but no technical detail beyond what the schema provides, matching the baseline for high schema coverage.

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 clearly states what the tool does: it reports site performance over a period compared with the previous period, covering clicks, impressions, CTR, average position, and their changes. It is identifiable as a site-level overview distinct from page/query-focused siblings, though it lacks an imperative verb and does not explicitly name sibling alternatives.

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 phrase 'Start here for "how is my site doing"' gives an explicit entry-point use case, so an agent knows when to reach for this tool. It does not state when not to use it or point to alternatives for deeper questions, but the intended context is clear.

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