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

Annotations already declare this as a read-only, idempotent, non-destructive operation. The description adds useful content context by specifying real-visitor Core Web Vitals and audit history, but it does not clarify date-range behavior, return granularity, or how the audit history is bounded.

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 one compact sentence with no filler and puts the key returned resources up front. Its extreme brevity makes it slightly less clear as a standalone statement, but it is appropriately concise.

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?

The schema and annotations cover invocation and safety well, and the description states the broad return categories. However, with no output schema, it does not explain the shape or detail of the performance and audit data, and it offers no usage context for this multi-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 all seven parameters including website, period, filters, device, and model are already documented in the schema. The description adds no parameter-level meaning beyond that, making the baseline score 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 names the specific resource returned: real visitors' Core Web Vitals plus the latest daily site audit and its history. It is clear what data the tool exposes, though it does not explicitly differentiate it from related siblings such as get_audit_findings.

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 guidance on when to use this tool versus alternatives, nor any exclusions or prerequisites. With many performance- and audit-related siblings, the agent is left to infer routing on its own.

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