Create Ad Group

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

With no annotations, the description carries the burden of disclosing behavior. It usefully explains the billing event constraint and max_bid_micros units, but omits what the API returns on success, idempotency behavior, and prerequisites like campaign existence.

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 well-structured: the purpose leads, followed immediately by the two most error-prone specification details. No filler or repetition.

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 create operation with 9 parameters, no annotations, and no output schema, this description covers the most critical constraints but leaves gaps: it does not state the response shape, whether a created ad group ID is returned, or how idempotency_key behaves. It is adequate but not fully complete.

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 coverage is 100%, so the baseline is 3, but the description adds meaningful semantics beyond the schema: billing_event_type constraints tied to campaign objective and max_bid_micros unit conversion with concrete examples. These are genuinely useful enrichments.

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 an ad group under a campaign.' This clearly identifies the action and the parent relationship, distinguishing it from tools like create_campaign or create_ad without being tautological.

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 gives clear, actionable guidance: billing event must match the campaign objective, with explicit mappings for CPM, CPC, and oCPC. It does not explicitly compare against sibling create tools, so it stops short of a 5.

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