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

Annotations cover the safety profile (readOnly=false, destructive=false, openWorld=true), so the bar is lower, and the description adds genuinely useful context: credit cost scales with frame rate and duration, and it returns a project id to poll via wait_for_video_project. It doesn't mention auth or approval requirements, but the async chain and cost warning are real added value.

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?

Two tight sentences, front-loaded with the verb and resource, followed by capability and cost/return facts. No filler or redundancy.

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 an output schema exists, return values needn't be described, yet the description helpfully flags the project id and the wait_for_video_project hand-off. With 7 parameters, nested objects, and conditional enums, the description could say slightly more about required inputs (e.g., that audio/assets drive prompt_type), but overall it is sufficient for correct invocation.

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 100%, so the schema already documents every parameter including the enums, nested style object, and conditional requirements. The description only loosely maps 'art and camera settings' and 'initial image and audio' to those fields, adding little beyond the schema — baseline 3 is appropriate.

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?

States a specific verb and resource ('Creates a stylized animated video') and enumerates the two prompt modes plus optional image/audio inputs. It doesn't explicitly contrast itself with near-neighbors like create_video_from_image or create_video_from_audio, so sibling differentiation is only implied by the 'animated video with art styles' framing.

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?

Mentions the audio-derived prompt mode constraint only indirectly ('custom prompt or an audio-derived prompt mode'), and names wait_for_video_project as the follow-up, which implies an async workflow. However, it never says when to pick this tool over the many other video-creation siblings, leaving selection to inference.

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