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

With no annotations, the description carries the behavioral burden. It discloses that the data is live from Meta, that the result is only safe if empty before deletion, and notes that deleting an audience auto-pauses dependent ad sets. It could go further on rate limits or explicit non-mutation guarantees, but the 'List' verb and deletion context make the read-only nature clear.

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 sentences carry purpose, output shape, use cases, a safety implication, and a grouping tip. There is no filler, and the primary purpose is front-loaded before the usage guidance.

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?

For a tool with no output schema and no annotations, the description explains the return fields, the safety condition, and where to get the required ID. Pagination behavior is left to the schema, which documents it well. A brief note on the overall response format would push this to a 5.

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%, so the baseline is 3. The description points to adsap_list_custom_audiences as the source for custom_audience_id, but the schema already says this. It adds no substantial parameter-level meaning beyond what the schema provides.

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 opens with a specific verb and resource: 'List the ads that use/target a given custom audience' and specifies the key output fields (ad set and campaign id). It clearly distinguishes this from the many sibling list/get tools by tying the result to a custom audience and adding 'live from Meta.'

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 use cases: use before deleting an audience, and to answer 'where is this audience used?'. It even clarifies that an empty list means deletion is safe. It does not explicitly name alternative tools to avoid, so it falls just short of a 5.

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