Draft a responsive search ad

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

Given the annotations (readOnlyHint: false, destructiveHint: false) which are ambiguous, the description adds critical transparency by stating it returns a preview and does NOT create the ad, and that confirm_and_apply is needed to execute. This clearly communicates the tool's non-destructive, non-read-only 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 concise overall, but there is minor redundancy: the opening line 'returns a PREVIEW, does NOT create the ad' is reiterated later with 'Call confirm_and_apply to execute.' The structure uses clear bullet points for the headline/description format, making it scannable, but a small trim would improve efficiency.

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 drafting tool, the description covers the essential context: what it does, its relationship to confirm_and_apply, and the critical input constraints. It does not describe the preview's content or error scenarios, but given the tool's straightforward nature and the presence of sibling tools, this is reasonably complete.

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?

The schema has zero description coverage for parameters, so the description must compensate. It thoroughly explains headlines and descriptions (including constraints and pinned object format), but leaves ad_group_id, final_url, path1, path2, and customer_id without any explanation. While some may be self-explanatory, the description only partially covers the parameter semantics.

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's purpose: to draft a responsive search ad and return a preview without creating it. It explicitly distinguishes itself from the confirm_and_apply tool, leaving no ambiguity about its role.

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 provides concrete usage guidance: it mentions the need to call confirm_and_apply for execution, specifies the required number and character limits for headlines and descriptions, and explains the pinned format. It also clarifies that this tool does not create the ad, acting as an explicit when-not-to-use indicator.

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