Set Campaign Target Cpa

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

Annotations only declare destructiveHint=true; the description adds prerequisites and failure modes the annotations cannot convey: the bidding-strategy requirement, the ~30-conversion history floor, and delivery throttling from setting tCPA too early or too low. It stops short of saying what happens on an invalid campaign or whether the change is reversible.

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?

Two short sentences, zero filler. The operation is stated first and the risk guidance follows, which is the right front-loading for a mutation tool.

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?

With an output schema present, return values need no explanation, and the description covers the bidding-strategy prerequisite and the conversion-history threshold. It could say more about error behavior on a non-Maximize-Conversions campaign or whether validate_only is worth using first.

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 100% with units and meaning already documented for target_cpa, campaign_id, customer_id and validate_only. The description adds only indirect meaning ('too low throttles delivery') and no syntax or format detail, so the baseline 3 applies.

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 specific verb (sets/updates), a specific resource (target CPA on a campaign), and an explicit precondition (campaign must use Maximize Conversions bidding). No sibling tool touches tCPA, so an agent can route to it immediately.

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 a concrete when-to-use condition ('only do this once the campaign has ~30+ conversions of history') plus a warning about the consequence of premature or low values. It does not name an alternative tool for campaigns on other bidding strategies, which is the only gap.

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