campaign_create_preview

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description contributes one genuinely new behavioral fact — that a receipt is issued with a ten-minute lifetime — but leaves critical mechanics unexplained: whether the receipt must be redeemed, what it contains, and what happens after expiry.

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?

A single front-loaded sentence with zero filler, and the action is stated first. It is terse to the point of leaving the workflow implicit, but nothing in it is wasted or buried.

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 deeply nested create-payload tool with conditionals, unstated invariants (adAccountId must match), and a multi-step preview/apply flow, one sentence is not sufficient. The output schema covers the return value, but the description never explains the receipt's purpose or the follow-up call, which is the highest-value missing context.

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%, and the input schema carries rich per-field guidance (APPSTORE-only supply source, APPSTORE_APP promoted type, bid strategy conditionals). The description adds no parameter meaning of its own, so the baseline 3 applies for a schema that 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 ('Preview creation') and resource ('one campaign'), which clearly separates it from campaign_update_preview or campaign_delete_preview. It does not, however, explicitly name a sibling or state the scope constraints (dry-run only, nothing persisted).

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?

No explicit when-to-use, when-not-to-use, or alternative is given. The 'ten-minute receipt' hint faintly implies a preview-then-apply workflow (operations_apply / operations_verify), but the agent must infer that entirely, and nothing warns that this call does not actually create the campaign.

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