List custom audiences

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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds only the account-scoping context ('in an ad account'); it says nothing about pagination behavior, result volume, or defaulting, and no output schema exists to carry that elsewhere.

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?

A single front-loaded sentence with no wasted words. It is appropriately terse for a simple list tool, though it sacrifices any routing or behavioral detail for that brevity.

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 read-only list tool with full schema coverage and annotations covering safety, the definition is minimally adequate. It omits output-shape hints and any disambiguation from the many sibling audience-listing tools, leaving gaps an agent must close on its own.

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 all five parameters (including the '='/'@' name-filter pattern, max_pages, page_size, page_token, and ad_account_id default) are fully documented in the schema. The description adds no parameter meaning beyond that, so the 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?

States a specific verb ('List') and resource ('custom audiences') and usefully defines what that resource encompasses (customer lists, retargeting, lookalikes). It does not, however, distinguish this list operation from sibling get_custom_audience or the other custom-audience tools.

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?

There is no guidance on when to use this versus get_custom_audience (single fetch) or list_saved_audiences / list_third_party_audiences. The agent must infer the listing use case purely from the name.

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