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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is covered. The description adds useful output context by listing what is returned (type, approximate size, status, source), which matters since there is no output schema. It says nothing about pagination, account scoping, or how many rows come back at default detail, which are the traits most likely to trip an agent.

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?

One compact sentence with no filler, and the field list is front-loaded. It loses a point for being a fragment with no verb phrase, which leaves the operation (list vs. read) implicit.

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?

Without an output schema, the description carries the burden of telling the agent what comes back, and it does so by enumerating the four fields. Combined with annotations covering read-only safety and a fully documented schema, an agent has enough to call this correctly.

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%: detail, folder, account, and language are all documented, including the summary-vs-full tradeoff and the Arabic language note. The description adds no parameter meaning beyond the schema, 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?

Names the resource (custom and lookalike audiences in the account) and the fields surfaced, which distinguishes it from generic campaign tools. But it is a bare noun phrase with no verb, and it does not distinguish it from the closely related siblings meta_saved_audiences, meta_create_audience, or meta_create_customer_list_audience. An agent can guess it is a read/list tool, but must infer that.

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 meta_saved_audiences, meta_targeting_search, or the audience-creation tools. No prerequisites, no exclusions, no statement that it is a listing operation. The only usage hint lives in the schema's 'detail' parameter, not in the description.

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