keyword_performance

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

Annotations already declare readOnlyHint=true, so safety is covered. The description adds meaningful behavior beyond that: results are sorted by cost with biggest spenders first, and the QS components are included because the single quality-score number alone is ambiguous. This is genuinely useful context.

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?

Three sentences, each earning its place: output contents, sort order, and diagnostic use case. The most decision-relevant information is front-loaded, and there is no filler.

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 output schema exists and annotations cover the read-only safety profile, so return-value and permission details are not required. However, with 8 parameters and zero schema descriptions, the tool description leaves parameter semantics to default titles, which is adequate for simple fields but incomplete for date and filtering behavior.

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 0%, so the description carries the burden of explaining the 8 parameters, but it names none of them. Parameter titles like zero_conversions_only and min_impressions are somewhat self-explanatory, but the description does not compensate for the missing schemas or clarify how parameters interact.

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 resource (per-keyword performance) and a diagnostic purpose (find keywords spending without converting), listing quality score, its three components, and effective bid. The scope is clear and distinct from broad siblings like performance, though it does not explicitly name an alternative tool.

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?

Gives an explicit use case: 'Use this to find keywords spending without converting' and explains how to act on the output by inspecting AdRel/LPExp/ExpCTR to diagnose low quality score. It does not mention when to prefer related siblings such as search_terms or performance.

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