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

Annotations already declare readOnlyHint, idempotentHint and non-destructive behavior, so safety is covered. The description usefully adds the paired-test methodology and that results distinguish real change from normal variance. It does not say what happens when fewer than two measurements exist or how large the pair lists are.

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?

One front-loaded sentence that names the comparison, the methodology, and the two result categories with no filler. It is dense but each clause carries information.

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?

An output schema exists, so return values need not be explained, and the description gives a good conceptual model of the comparison. It still omits prerequisites such as needing at least two measurements and how this differs from the neighboring visibility tools, leaving gaps for a zero-required-parameter tool.

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 site and the three cursor parameters are fully documented in the schema. The description adds no parameter meaning beyond what is already structured, which is the correct baseline.

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?

States a specific verb-plus-resource: it compares the two latest comparable measurements and reports gained/lost pairs plus whether the change is statistically real. An agent can tell it apart from get_ai_visibility or get_weekly_summary, though no sibling is named explicitly.

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?

Usage is only implied by 'between the two latest comparable measurements'; there is no explicit when-to-use, when-not-to-use, or pointer to an alternative such as get_ai_visibility for absolute levels. The agent must infer the comparison scenario itself.

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