create_lookalike_audience

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

No annotations are present, so the description carries the full burden of behavioral disclosure. It only says 'creates' and explains ratio semantics; it does not disclose side effects, async processing time, required permissions, or what happens to the source audience. This is minimal transparency for a creation operation.

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 front-loaded: one clear action sentence followed by a concise explanation of the only non-obvious parameter. Every sentence contributes value without repetition or filler.

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?

The description plus output schema is sufficient to attempt invocation: required parameters are visible in the schema and ratio is explained. However, it lacks explicit routing to alternatives, prerequisites for the origin audience, and any note about creation latency or status, so completeness is only adequate.

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 schema has 0% description coverage, and the description compensates only for the ratio parameter by explaining the 0.01–0.10 range and precision tradeoff. Other parameters (ad_account_id, name, country, origin_audience_id) are left entirely to their names and defaults, though those are reasonably self-explanatory.

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: it creates a lookalike ('similar') audience from an existing audience. This distinguishes it from the sibling create_custom_audience, which builds a custom audience rather than a lookalike, and the French phrasing maps directly to the tool's function.

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?

No guidance is given about when to use this tool instead of other audience tools like create_custom_audience, list_custom_audiences, or get_custom_audience. The only contextual hint is 'from an existing audience', which implies a prerequisite but does not explain when selecting this tool is appropriate.

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