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

The description implies a read-only 'preview' operation, but annotations set readOnlyHint to false, indicating a possible side effect. This contradiction undermines transparency. Additionally, the description does not disclose any other behavioral traits such as rate limits or data impact. A score of 2 reflects the lack of clarity and contradiction.

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 concise at 4 sentences, with the purpose stated first. However, the omission of parameter documentation is a structural gap that reduces clarity. Still, it is efficient and front-loaded.

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 the tool's complexity (preview with ads, multiple parameters, no output schema), the description is incomplete. It focuses only on authorization and omits functional details like what the preview produces or how parameters affect the result. Critical context is missing.

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?

The input schema has 4 parameters, but the description provides no explanation of their meaning or usage. With 0% schema coverage, the description fails to compensate. The only context is business logic, leaving agents to guess parameter roles.

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 'Generate a preview for a Magic Audience campaign with ads,' which clearly identifies the verb and resource. However, it does not explicitly distinguish this tool from the sibling 'generate_magic_audience_campaign_with_ads,' which may create or save a campaign. A score of 4 is given because the purpose is specific but lacks sibling differentiation.

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 explicit preconditions: check business permissions, note that FREE businesses cannot use it, call check_business_tool_access first, and handle grace-period warnings. It clearly states when not to proceed. This level of guidance is comprehensive and exceeds typical descriptions.

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