ad_manager_fb_update_custom_audience

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

Annotations already indicate it is a write operation (readOnlyHint=false) and idempotent (idempotentHint=true), which the description's 'Update' verb confirms without adding new behavioral detail. It does not disclose whether it performs a full replacement or partial update, or any side effects. Since annotations cover the basic safety profile, the description adds minimal value but does not contradict them.

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 extremely succinct ('Update custom audience'), with no unnecessary words. It is front-loaded and efficient. However, it is so brief that it may sacrifice informative value, though that is more a completeness issue than a conciseness problem.

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?

The description is insufficient for an agent to use the tool correctly. It does not specify that 'name' and 'description' are required fields, what happens to unspecified fields, or any prerequisites (e.g., existing audience, integration). It also omits the optional locationId default behavior. Given the lack of an output schema and the presence of multiple similar tools, more context is needed.

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 schema provides full descriptions for all four parameters (100% coverage), so the description does not need to explain them. It adds nothing beyond the schema, but the schema already carries the burden. Baseline 3 is appropriate.

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 states a specific action ('Update') and a specific resource ('custom audience'), which clearly identifies the tool's purpose. However, it does not differentiate from sibling tools like update_campaign or upsert_audience, so it lacks explicit distinction from other update/upsert operations.

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 provides no guidance on when to use this tool versus alternatives. It does not mention when to use it (e.g., when modifying an existing audience) or when not to use it (e.g., for creation or upsert). No context or exclusions are given.

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