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

Annotations declare a destructive open-world write, and the description adds real context beyond that: the confirmation-receipt requirement, idempotency-key requirement, automatic draft continuation that stops short of executing, and that Review Sandbox simulates writes and skips continuation. It does not spell out rollback/irreversibility of a completed ad write, which is the main remaining gap for a destructiveHint=true tool.

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?

Four front-loaded sentences that each carry content: purpose, scope, continuation caveat, sandbox caveat. Some of it duplicates the applyContinuation schema description, but nothing is padded 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?

With an output schema present and full parameter documentation, the description fills the remaining gaps an agent needs: the confirm-then-apply gate, idempotent retry framing, the automatic continuation behavior, and the sandbox exception. Nothing material about invoking this destructive write is missing.

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 already documents planId, idempotencyKey, confirmationReceipt, and the applyContinuation internals in detail. The description adds only the high-level statement that a receipt and idempotency key are required, which is a restatement rather than new semantic detail. Baseline 3 applies.

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 ('Executes only a confirmed AD_AD_CREATE plan') and the resource created ('Sponsored Products product ads or Sponsored Display product ads'). The 'only a confirmed ... plan' qualifier plus the creation framing distinguishes it from apply_product_ad_changes and the prepare_* siblings without needing to open any schema.

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 gates use on a confirmed plan with a one-time confirmation receipt and an idempotency key, which functions as a when-to-use prerequisite. It also describes the follow-on scenario ('A linked structure draft may automatically prepare the next preview without confirming or executing it') and how Review Sandbox differs, so the agent knows both the entry condition and the post-call behavior.

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