Create Custom Audience

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

Annotations indicate a non-read-only, non-destructive creation. The description adds important behavioral context: it only creates the container, not populates it. No contradiction with annotations. Missing details on authorization or rate limits, but still strong.

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?

Well-organized with bullet points for types and structured args. Every sentence adds information; no fluff. Concise yet comprehensive.

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?

Mentions return value (audience ID) despite no output schema. Covers prerequisites and separate population step. Could include error handling or common pitfalls, but overall sufficient for a creation tool.

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 57% but the description adds meaning beyond enums (e.g., example for ad_account_id, explanations for subtype, customer_file_source requirement, retention_days range). Adds value while not repeating all schema details.

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 tool creates a custom audience in a Meta ad account, lists supported types (CUSTOM, ENGAGEMENT, VIDEO) with specific context, and distinguishes from sibling tools like lookalike or saved audiences.

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 context on when to use each subtype (e.g., CUSTOM requires Pixel, etc.) and notes that populating the audience is separate, but lacks explicit guidance on when not to use this tool versus alternatives like meta_create_lookalike_audience or meta_create_saved_audience.

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