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

Annotations already declare readOnlyHint=false, openWorldHint=true, and destructiveHint=false, so the safety profile is partly covered. The description adds only 'in-place' (mutates the existing ad) and 'library-creative' source, but omits the critical trait that this is a staging step whose effect requires a separate confirmation, which no annotation reveals.

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?

It is a single front-loaded sentence with no wasted words, which is structurally clean. However, for a 9-parameter mutation tool it is under-specified rather than genuinely concise, leaving all detail to unannotated, undescribed fields.

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 values need not be explained, but for a 9-param write tool with 0% schema coverage and no annotation detail, the description omits the two-phase workflow, the meaning of the input fields, and any side-effect context. It is not complete enough 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 0% across 9 parameters, and the description clarifies none of them. The tool has heavily ambiguous overlapping parameters (ad_id vs account_id vs ad_account_id; creative_name vs creative_names vs new_creative_name vs replacement_creative_name), and the description provides zero disambiguation, so it fails to compensate for the coverage gap.

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 names a specific verb+resource: 'Prepare ... creative swap on an existing ad,' with 'in-place' and 'library-creative' scoping the target and source. It is clearly a preparation step, but it does not distinguish itself from the sibling confirm/deny tools that the name pattern implies, so a 5 is not warranted.

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?

There is no when-to-use guidance, no prerequisite (e.g., you must later call ads_replace_creative_confirm to apply the swap), and no mention of the prepare/confirm/deny siblings. An agent gets no routing information from the description.

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