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

Exceptional disclosure beyond the annotations: job semantics (1-3 minutes), 20-second synchronous wait, credit cost (5/10, refunded on failure), plan gating, and the narration-retention nuance for walkthroughs vs other formats. All consistent with the non-idempotent, non-destructive write 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?

Front-loaded with "Beta" and the core action, then layers cost, timing, and preconditions. Dense but every sentence carries operational information; the run-on quality of the first sentence slightly hurts scannability.

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 no output schema, the description carries the return contract well: it either returns the finished video or its progress state. Also covers plan/permission gates and credit spend. Only minor gaps remain around what the progress payload contains.

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 covers 73% of parameters, and the description adds real meaning on top: what proof means (never invented, so omit it and none is shown), how narration behaves per format, and that look can be omitted to let the director choose. A few parameters (title, aspect, lengthSeconds) are covered only by schema.

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: an AI director makes a motion video from a brief and/or demos, with a described pipeline (storyboard of 10-15 beats, gathers screens/b-roll/music, designs scenes, records narration). This clearly distinguishes it from read-side siblings like get_video, though it never explicitly contrasts with create_video, which is the most likely point of confusion.

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?

Gives an explicit follow-up rule: if the job is still "generating" after the 20-second wait, call get_video rather than generating again. It also states prerequisites (demos:read/write, verified email on Free plan). It stops short of explaining when to prefer this over create_video.

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