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

Annotations only carry the safety profile (readOnly=false, idempotent=false, destructive=false); the description supplies the genuinely important behavioral trait: this is asynchronous, returning an id immediately while generation runs for minutes, and video_status is the way to learn when the file link is ready. That is exactly the context an agent cannot get from annotations or schema.

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 sentences, front-loaded with the usage trigger, then the async lifecycle, then the storage side effect. No filler and nothing repeated from the schema or annotations.

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 present, return values need not be described, and the async lifecycle plus library persistence are covered. It omits any note on cost/credits or generation failure handling, which would be the only remaining gap for a long-running generation 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 description coverage is 75%, near the 80% baseline where the schema already documents aspect, prompt, and duration; only title is undocumented. The description adds no parameter-level detail beyond the generic "from a description" phrasing, so it neither compensates nor detracts.

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 names a specific verb (create) and resource (short AI video clip) plus the trigger input (a description), so the purpose is unambiguous. It does not, however, explicitly distinguish itself from the closest sibling edit_video, leaving that differentiation to inference.

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?

"Use this when the user wants a short AI video clip made from a description" gives a clear activation condition and an implied scope limit (short clips). There is no explicit when-not or named alternative such as edit_video for modifying an existing clip, so it stops short of full routing guidance.

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