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

No annotations provided, so description carries full disclosure burden. Only adds 'formatted output' beyond the tool name. Fails to explain time-series aggregation behavior implied by granularity/daysBack parameters, whether data is cached/real-time, or output structure.

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?

Single sentence, 11 words with no waste. Front-loaded with verb and object. Efficient structure, though arguably too brief given the tool's 11-parameter complexity and lack of annotations.

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?

Inadequate for tool complexity: 11 parameters with time-filtering, device/country segmentation, and statistical measures. No output schema or annotations to compensate. Description should explain the overview vs. breakdown distinction and typical analytics workflows.

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 has 100% description coverage, establishing baseline meaning for all 11 parameters. Description mentions 'Core Web Vitals' which maps to metric parameter options, but does not add syntax details or explain relationships between date parameters beyond schema definitions.

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?

Specific verb ('Gets'), resource ('domain performance overview'), and scope ('Core Web Vitals metrics') are clearly stated. However, it lacks explicit differentiation from sibling tools like get_page_performance_breakdown.

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?

No guidance provided on when to use this domain-level overview versus page-level breakdowns (get_page_performance_breakdown) or element-level analysis (get_cwv_element_breakdown). No prerequisites or alternatives mentioned.

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