Create ad group

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

Annotations only say readOnlyHint=false and openWorldHint=true, so the description carries the burden. It discloses that groups are PAUSED by default, that all groups in a campaign must share objective and product_type, that amounts are local micro-units, and that confirm_spend is required for ACTIVE. This is rich behavioral context beyond the schema.

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 compact and front-loaded. The first sentence states the core action, followed by high-value constraints and warnings. Every sentence earns its place, and the critical budget/bid/confirm_spend guidance is packed into a few lines.

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 12 parameters, no output schema, and sparse schema descriptions, the description covers the most decision-critical aspects: default state, budget location, bid behavior, micro-units, and confirm_spend. It doesn't explain placements, start_time, or entity_status, but those are less likely to cause incorrect invocation. The description is strong enough for an agent to call the tool correctly in most cases.

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 only 17%, so the description must compensate. It explains the key parameters: daily_budget_amount_local_micro / total_budget_amount_local_micro, bid_amount_local_micro (omitted = automatic), and confirm_spend (required for ACTIVE). It also clarifies the micro-unit semantics. It doesn't cover every parameter, but it adds meaning to the most important ones.

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 ('Create a line item under a campaign') and immediately distinguishes it from siblings by noting budget is set here and that all groups in a campaign must share objective/product_type. It clearly identifies what the tool does and how it differs from related tools like x_ads_create_campaign or x_ads_update_ad_group.

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 description provides explicit when-to-use guidance: budget is set HERE, bid omitted means automatic, and if creating multiple groups from one stated budget, ASK split vs each. It also warns that confirm_spend is required for ACTIVE. This gives an agent clear decision rules for using this tool versus alternatives.

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