create_custom_audience

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

With no annotations provided, the description carries the full burden of disclosing behavioral traits. It only says 'Create a custom audience list' which is essentially the tool name restated. It does not mention potential side effects, required permissions, return values, or whether the operation is idempotent. This is effectively no behavioral transparency.

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 sentence with no fluff, which is concise and front-loaded. However, it is so minimal that it lacks structured detail, though it does not waste words. It earns its place by stating the purpose but could be more informative without losing conciseness.

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 tool is a mutation with no annotations and no output schema, the description should explain what happens after creation, any prerequisites, or how it relates to other audience tools. It provides none of these. The complete schema mitigates some issues, but the description is inadequate for an agent to fully understand the tool's context and side effects.

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 four parameters have descriptions in the schema. The tool description itself adds no parameter meaning, but the baseline for high schema coverage is 3. The schema clearly explains name, customerId, description, and membershipDurationDays.

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 (create) and resource (custom audience list). It is specific enough to indicate a creation operation, but it does not distinguish this tool from sibling tools that also create audience types like create_customer_match_list or create_lookalike_audience. Thus it meets the 'clear but no sibling differentiation' level.

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 such as create_customer_match_list or create_lookalike_audience. There are no prerequisites, context, or exclusions mentioned, leaving the agent without direction on selecting this tool.

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