Performance Max asset performance

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

The annotations indicate readOnlyHint=true and destructiveHint=false, which align with the description's 'Returns' wording. The description adds a functional limitation (no performance labels) not covered by annotations, increasing transparency beyond the structured metadata.

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 concise and well-structured: a clear opening statement, a list of returned fields, a note on limitations with an alternative, and a parameter explanation. No redundancy or irrelevant detail.

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 description provides sufficient context for a read-only tool: it names the resource, the fields returned, and a relevant limitation. However, the missing explanation for customer_id and no mention of the output structure (though an output schema exists) leaves minor gaps, but overall it is adequate.

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%, and the tool description only explains campaign_id ('optional filter to a single PMax campaign'). The customer_id parameter is left entirely undocumented, leaving users to infer its meaning without additional guidance.

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 per-asset details for Performance Max campaigns, specifying the exact fields returned (field_type, primary_status, content). This is specific and unambiguous, distinguishing it from other asset-performance tools.

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 explicitly notes that per-asset performance labels are not available and directs the user to an alternative tool (get_detailed_asset_performance) when that capability is needed. It also explains the optional campaign_id filter, providing clear usage context.

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