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

Annotations already declare destructiveHint=true, idempotentHint=false, openWorldHint=true and readOnlyHint=false. The description adds substantial context beyond them: empty fields are resent unchanged, the whole creative is validated on every update, SPARK ad text/display name cannot be changed, and confirm=false previews the operation.

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?

Despite covering several edge cases, the description is front-loaded with the core purpose and then layers constraints efficiently. Every sentence carries operational value, and there is no redundant restatement of the tool name.

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?

Given the available annotations, the existing output schema, and the tool's complexity, the description is complete enough for correct invocation. It covers mutation behavior, preview mode, platform-specific limitations, and sibling-tool disambiguation without needing to explain return values.

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 0%, so the description must compensate, and it does for most parameters: it explains empty-field behavior, names the editable creative fields, gives CTA examples, and explains confirm=false. It does not, however, explain the roles of the required advertiser_id, adgroup_id, and ad_id parameters beyond implied identity context.

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: it updates a TikTok ad's creative in place, naming the editable fields (ad text, landing page, call-to-action, display name). It clearly distinguishes itself from status-change siblings by noting that until now only status could be changed.

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 explicitly routes the agent: use this to fix typos or swap landing pages without deleting/recreating the ad, while posting status updates belongs elsewhere. It also states when-not conditions, including SPARK ad limitations and that Upgraded Smart+ campaign ads cannot be edited via API.

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