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

No annotations are provided, so the description carries the full burden. It usefully discloses the side-effect profile ('Sends nothing, no credits'), the READY precondition and the return shape, but says nothing about idempotency — whether calling twice creates duplicate campaign audiences — or about permissions/errors when the audience is not READY.

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?

Three tight clauses: what it produces, what to do with it, and what it costs. Front-loaded with the transformation and the return value; no 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?

With no output schema, the description compensates by describing the return object, and it covers cost/preconditions for a two-parameter tool. What remains missing is mutation semantics (duplicate creation on repeat calls) and failure behavior for a non-READY audience.

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%, including the default for `name`, so the schema already does the work. The description adds no parameter-level meaning (it only mentions the output id being reusable as audienceId elsewhere), so 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?

Specific verb ('Turn a READY custom audience into a campaign audience') plus resource plus stated return value. The 'READY' precondition and the downstream hand-off to create_campaign make it clearly distinguishable from create_custom_audience or add_custom_audience_contacts.

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?

Clear context: the tool is the step between having a READY custom audience and calling create_campaign with the returned id, described as the 'Launch campaign' button of My Audiences. It does not name alternatives or state when NOT to use it (e.g., if the audience is still enriching).

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