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

Annotations only say readOnly=false and destructive=false, so the description carries the burden of operational behavior. It discloses the ~150 credit cost, the few-minute runtime, the ~2-minute wait, and the fact that it returns an id for fattly_video_status checks. This is meaningful behavioral context beyond 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 compact and front-loaded with the most important fact: this is a premium VIDEO ad with a real speaking creator. Each sentence contributes a distinct piece of information—what it produces, credit cost, timing, and the follow-up status flow—with no filler.

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?

For an 11-parameter tool with a rich schema and no output schema, the description supplies the missing operational context: credit cost, wait behavior, and the returned id for status checking. It does not explain every input, but the schema already covers those details adequately.

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 the parameters are already well documented. The description reinforces the core flow around product, creator, and script but does not add meaningful parameter-level semantics beyond what the schema provides.

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 verb and resource: this generates an Ad Studio VIDEO ad where a creator holds the product and speaks the script with a real voice. It clearly differentiates from generic video generation and likely image-ad siblings by emphasizing the product+creator+script flow.

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?

It provides contextual cues about when this is appropriate: premium, real-voice, full site flow with product and creator. However, it never explicitly says when to prefer this over siblings like fattly_generate_ad or fattly_generate_video, nor does it list any exclusions.

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