Performance By Country

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

No annotations are provided, so the description carries the full disclosure burden, and it adds nothing: no mention of default date windowing, row-limit behavior, rate limits, or authentication needs. The schema does encode defaults (28-day window, row_limit 100), but the description offers no behavioral context beyond the title.

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?

A single short sentence with no filler and the grouping dimension front-loaded. It is efficient, though its brevity borders on under-specification rather than tight writing.

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 described, and the schema covers parameters well. Still, for a tool in a family of four 'performance_by_*' siblings with no annotations, the description should at minimum say what metrics are reported and how it differs from the other breakdowns.

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%, including enum values, defaults, and the date-window default, so the schema fully documents all six parameters. The description adds no additional parameter meaning, which is the expected baseline when the schema does the heavy lifting.

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 phrase 'Performance broken down by country' names the resource and the grouping dimension, which loosely distinguishes it from siblings like performance_by_date. However, 'performance' is never defined (clicks, impressions, CTR, position?), so the purpose is only implied rather than stated with a concrete verb/resource pair.

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 performance_by_date, performance_by_device, or performance_by_search_appearance, nor any mention of prerequisites such as which site properties are valid. The agent must infer usage purely from the tool name.

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