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

Goes beyond the annotations: explains that drafts are temporary, expire in 7 days if unkept, and that this call itself may delete expired drafts — which is precisely the destructive behavior behind destructiveHint=true. Adds real context. It stops short of saying how reuse matches an existing draft or whether deletion affects other sessions' drafts.

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?

Three short sentences, front-loaded with the action and output, then scope exclusions, then lifespan behavior. No filler; every sentence adds a fact.

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?

With an output schema covering the return value and annotations covering safety profile, the description supplies the remaining essentials: source of inputs, non-publishing scope, and draft expiry. The main gap is the handoff to interests_keep_draft for retention, which matters for correct usage.

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?

One parameter with 0% schema description coverage, so the description must carry the load. It usefully says targets come from targeting_search picks, which explains the {targeting_type, id} shape conceptually, but does not describe the enum values or id format expected. Partial compensation only.

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?

Specific verb+resource: creates or reuses a temporary audience-targeting draft in AdsAgent, names the source (targeting_search picks) and the returned value (interest_pack_name). An agent can distinguish it from interests_save_targets or interests_archive without opening schemas.

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 'from targeting_search picks' clause establishes the pipeline context and when to call it. The negative scope statement ('does not create, publish, or modify Meta ads') rules out an expected misuse. However, it never names the natural follow-up sibling interests_keep_draft or contrasts with interests_save_targets, so the alternative routing is only implied.

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