Add an ad group

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

Annotations only supply readOnlyHint=false, so the description still carries most of the burden. It does not say whether this is purely additive, whether it needs a connected ad account, or what side effects occur on the parent campaign.

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 short sentence, but the 'or more ads' clause introduces ambiguity rather than value, so brevity comes at the cost of precision.

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 mutation tool with an empty parameter schema, no output schema, and only a readOnlyHint, the agent is left without any indication of how the ad group is specified or what is returned. The description does not fill that gap.

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?

The schema declares zero parameters, so there is no parameter semantics to document; baseline for a 0-param tool is 4. The description adds nothing here, but nothing is required of it.

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 verb and resource ('Add an ad group'), which matches the title and readOnlyHint=false. However the trailing 'or more ads' muddies what the tool actually creates, and it offers no differentiation from siblings like launch_campaign or launch_meta_ad.

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?

'to a campaign you already have' hints at a prerequisite (an existing campaign), but there is no explicit when-to-use guidance and no alternative named among the many launch_* siblings.

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