Draft callouts

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

With annotations already declaring readOnly=false and destructive=false, the description adds meaningful context: this is a staged write that produces a plan_id and mutates nothing until confirm_and_apply runs. That two-phase behavior is not derivable from the annotations alone and is exactly what an agent needs to avoid assuming an immediate mutation.

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-loads the preview semantics in the first sentence, then explains the plan_id/confirm mechanism. Slightly padded by the trailing Google Ads API documentation link, which adds little for an agent already invoking this tool.

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 exists, so return-value details need not be described, and the description still covers the crucial plan_id/preview contract. The preview-then-confirm workflow plus the 25-character callout constraint already in the schema makes this sufficient for correct invocation.

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 campaign_id, callouts, and customer_id are fully documented in the schema. The description adds no additional parameter meaning beyond what the schema provides, which is the expected baseline when the schema does the heavy lifting.

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 ('Draft campaign callout assets') and immediately clarifies it returns a preview rather than applying changes. It does not name which sibling to use instead (e.g., draft_sitelinks, draft_structured_snippets), but the resource noun makes it distinguishable from the other draft_* asset 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?

Explicitly routes the agent to the follow-up tool: 'nothing changes until confirm_and_apply applies it', which tells the agent both when this is used and what the next step is. No explicit exclusions or when-not-to-use conditions, but the staged workflow is clear.

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