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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, which cover the safety profile. The description adds no extra behavioral context beyond restating the listing action; it does not mention pagination, rate limits, or data scope, but it is consistent with the annotations.

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 a single, concise sentence that gets straight to the point. It contains no redundant or extra content, and the information is front-loaded. This is ideal for a simple list operation.

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?

Given the lack of output schema, the description should at least clarify the return format or any important limits. It does not address parameter usage, authentication requirements, or result scoping. The tool is part of a large sibling set, and without additional context, the agent may not know how to invoke it 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?

The input schema lists 'account' and 'auth_account' with no description in the schema or the tool description (schema coverage 0%). The description mentions 'ad account' but does not explicitly link it to the 'account' parameter, and 'auth_account' is completely unexplained. No parameter meaning is added beyond the raw names.

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 clearly states the action ('List') and the resource ('Custom Audiences in the ad account'), making the purpose unambiguous. It is specific enough to differentiate from tools like meta_ads_campaigns or meta_ads_audience_delete, though it does not explicitly name alternatives.

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 provided on when to use this tool versus alternatives such as meta_ads_audience_write_create or meta_ads_audience_delete. The description simply states the operation without context on prerequisites, intended scenarios, or when to prefer other audience tools.

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