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

Annotations already declare readOnlyHint=false, destructiveHint=false, and openWorldHint=true. The description adds only 'preserving media and Page,' a useful guarantee, but it fails to explain what 'prepare' actually does—whether changes are staged before confirmation, whether it mutates anything immediately, or what side effects occur. This is a significant gap for a mutating tool with minimal annotation depth.

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 a single, front-loaded sentence that states the core purpose and a key constraint without any redundant wording. Every word earns its place, and it is easily scannable.

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 5-parameter tool operating in a multi-step prepare/confirm/deny workflow, this description is too thin. It does not clarify which fields are required beyond the schema, what the tool returns (even with an output schema, parameter guidance is missing), or any prerequisites like ad existence or permissions. The description leaves critical decisions to inference.

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. It mentions body/title/description edits, mapping loosely to the body, title, and description parameters, but never explains their format, optionality, or relationships. ad_id and ad_account_id are left entirely to the schema, and no additional semantics are provided for any parameter.

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 a specific verb (Prepare), resource (body/title/description edits), and a precise scope (on the same Ad ID, preserving media and Page). This distinguishes it from sibling tools like ads_replace_creative_prepare and ads_replace_page_prepare, which target different components.

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 constraint 'preserving media and Page' implies this tool is for copy-only edits, but it does not explicitly say when to use it versus alternatives such as ads_replace_creative_prepare or ads_replace_page_prepare. No mention of the confirm/deny workflow or any disqualifying conditions, so guidance is implied rather than explicit.

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