Create ad plan (campaign)

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

Annotations already indicate it's a write operation. The description adds that money fields are in account currency and that `extra` is merged verbatim, but does not disclose idempotency or error behavior.

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 sentences with no waste: first states purpose, second adds two important notes about currency and the `extra` parameter.

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?

Lacks details about return values or error conditions, which would be helpful given no output schema and 9 parameters.

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 description adds marginal value beyond the schema, only highlighting the currency context for certain numeric fields.

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 clearly states the verb 'Creates' and the resource 'ad plan (campaign)', distinguishing it from sibling create tools like create_ad_group and create_banner.

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 gives a hint about using the `extra` field for complex fields but does not explicitly state when to use this tool versus alternatives like list or update tools.

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