Performance Max asset combinations

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is covered and the description only needs to add context. It does add useful framing about what is returned ('each combination with the assets used and their field types'), but discloses nothing about pagination, ranking cutoffs, or any scope limits on 'top-performing'.

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?

Front-loaded with the core purpose and kept to four tight sentences. The trailing Google Ads API documentation link adds little selection value, but otherwise 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?

With an output schema present and annotations carrying the safety profile, the description only needs to orient the agent, which it does. The remaining gap is routing guidance against the other PMax read tools, which no structured field supplies.

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 coverage is 100% and both parameters are fully documented, so the baseline is 3. The description adds no parameter-level meaning such as date-range scoping for the performance data, which a 'top-performing' tool would plausibly need.

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 verb and resource ('Get top-performing asset combinations for Performance Max campaigns') and clarifies the granularity is combinations, not raw assets. This naturally separates it from siblings like get_pmax_assets and get_pmax_performance, but it never names those alternatives, so the differentiation is inferential rather than explicit.

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 explains what the data is good for ('helps identify which creative elements work well together') but gives no when-to-use guidance and no comparison to the closely related get_pmax_assets, get_pmax_performance, or get_asset_group_signals siblings. An agent must guess which of the four to call.

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