ad_update_preview

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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, and the description mostly restates the 'preview' idea. It adds no details about what previewing means here, such as whether it validates the payload, returns a diff, or has any side effects.

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 extremely short, front-loaded, and free of waste. Its brevity is structurally clean, although the missing detail is penalized in other dimensions.

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?

For a tool with four required parameters, a nested payload, and real sibling alternatives, the description does almost nothing to explain the preview workflow. The output schema and annotations reduce some burden, but an agent still lacks essential context on the tool's role.

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 100%, so the schema itself documents profile, adAccountId, id, and the nested payload fields. The description adds no parameter meaning beyond that baseline, which is acceptable only because the schema is complete.

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 states a specific verb and resource: previewing an ad update. It is clear what the tool acts on, but it does not distinguish this preview from nearby siblings such as ad_pause_preview, ad_resume_preview, or ad_group_update_preview.

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?

It gives no guidance on when to use this preview instead of ad_get, an apply operation, or other ad-related preview tools. The word 'preview' implies a pre-apply check, but no alternatives or conditions are named.

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