Audience performance

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds context about what data is returned and the limitation regarding PMax, which complements the annotations without contradicting them. No side effects or destructive actions are implied.

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 compact and well-organized: purpose statement, output details, usage note, and parameter notes. Each sentence adds value without redundancy, and the structure makes it easy to scan for key facts.

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?

Given that an output schema exists (though not shown) and the description enumerates the output fields and audience types, the description provides enough context for an agent to understand what the tool returns and when to use it. It also covers the date range defaults and the campaign filter, making it sufficiently complete for a straightforward read-only reporting 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 0%, so the description must compensate. It does clarify that campaign_id is an optional filter and states the date format (YYYY-MM-DD) and default behavior (empty = last 30 days). However, customer_id is left undocumented, and there is no explanation of how the parameters interplay (e.g., whether both campaign and customer can be specified together). This partial compensation earns a middle score.

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 clearly states the tool retrieves audience segment performance metrics, enumerates the metric fields (impressions, clicks, cost, conversions, CTR, CPC) and audience types (remarketing, in-market, affinity, demographics). It also distinguishes itself from PMax-related reporting, helping an agent choose this tool for explicit audience targeting scenarios.

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?

The description gives an explicit when-not scenario: PMax audience targeting is automatic and may not appear in this report, which implies the tool is intended for Search/Display campaigns with explicit targeting. However, it does not explicitly name an alternative tool (e.g., get_pmax_performance) for PMax cases, so the guidance is slightly less explicit than ideal.

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