Performance Max asset combinations

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

Annotations already indicate read-only and non-destructive behavior, which covers safety. The description adds that it lists assets and their field types, but does not mention any potential side effects, data freshness, or limitations. Since the annotations carry the primary safety signal, the description provides minimal extra transparency beyond clarifying its reporting nature.

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 somewhat redundant, repeating the campaign_id filter and restating the purpose, but it remains relatively compact and focused. It avoids unnecessary jargon and clearly conveys the tool's function without excessive length.

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 is provided, so the return format is defined. The description explains the purpose and gives a hint about the optional filter. It does not mention prerequisites or edge cases, but given the tool's straightforward read-only nature, it is reasonably complete for an agent to understand and call correctly.

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?

Only campaign_id is mentioned in the description as an optional filter, with no explanation for customer_id. The schema itself has no descriptions (coverage 0%). This leaves the meaning and purpose of customer_id ambiguous, though the description does clarify campaign_id's role.

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 it 'Get[s] top-performing asset combinations for Performance Max campaigns' and elaborates that it shows which headline, description, and image combinations Google selects most often. This distinguishes it from sibling tools like get_asset_performance or get_pmax_performance by focusing specifically on combinations.

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 does not provide any guidance on when to use this tool versus alternatives such as get_asset_performance or get_pmax_performance. It lacks information on use cases, scenarios, or why one might prefer this over other reporting tools.

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