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

Annotations only mark it non-read-only, non-destructive and non-idempotent, so the description carries real weight and delivers: campaigns start PAUSED, confirm=false is a dry-run, absent locations means worldwide targeting, and missing branding fails loudly rather than launching unbranded. These are exactly the behavioral facts an agent needs before calling.

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 core purpose and safety behavior are front-loaded, and the rest is dense with actionable detail rather than filler. It is long and occasionally parenthetical-heavy ('set True to enable'), but nearly every sentence earns its place.

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 10-parameter mutation tool with an output schema present, the description covers targeting, branding, dry-run and failure modes, so nothing material is left to inference. Return values are legitimately handled by the output schema.

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 carry the load, and it does: it defines locations format, languages codes, the inverted booleans search_partners and presence_only (with Google's default spelled out), business_name length and logo_asset_id requirements. Only the self-evident name, customer_id and daily_budget go unexplained.

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?

It states a specific verb and resource ('Creates a new Search campaign ... + daily budget') and immediately distinguishes itself from the many sibling campaign creators via the Search qualifier. The 'starts PAUSED for safety' clause adds scope an agent can act on.

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?

Gives clear conditions for behavior: no locations targets the entire world and can be fixed later via set_campaign_targeting, and the 3 targeting settings can be changed later via manage_campaign_settings. It does not explicitly route between this and the other create_*_campaign siblings, so it stops short of full when/when-not guidance.

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