generate_video

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

With no annotations provided, the description carries the full burden of disclosing side effects and behavior. It clearly states that the operation spends the account's credits, returns immediately with an id, and takes about a minute to render. It also discloses idempotent retry behavior (identical calls within two minutes return the same generation). It does not mention potential failure modes or authorization requirements, but the core behavioral profile is covered thoroughly.

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 a single, dense paragraph but is well-organized. It front-loads the core purpose and the critical cost warning, then follows with the immediate-return behavior, the companion tool for collection, and the idempotency rule. Every sentence carries needed information, and there is no fluff. It is appropriately sized for the tool's complexity.

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 no output schema and no annotations, the description covers the essential operational context: how to initiate, what to expect in terms of timing, how to retrieve results, and how to avoid extra charges. It explains the variants (prompt/image/reference) and the special relationship between imageUrl and endImageUrl with respect to model support. It omits details on some parameters, but the missing ones are largely self-explanatory from their names, so the overall picture is sufficient for an agent to call the tool correctly.

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 only 45%, so the description must compensate. It does explain key parameters: imageUrl (how it becomes the first frame, size limits, when to prefer it), referenceImageUrls (ordering with @Image1, @Image2, not combined with imageUrl), and requestId (idempotency usage). However, it offers no explanation for audio, quality, modelSlug, resolution, aspectRatio, or durationSeconds, which are left to their names alone. The partial coverage earns a 3.

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 opens with 'Generate a video from a prompt, from an image, or from a set of reference images,' which states a specific verb, the resource (video), and the three distinct input modes. This clearly distinguishes it from siblings like check_video and quote_video by naming the exact action. It leaves no ambiguity about what 'generate' means here.

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 description explicitly instructs to call quote_video first and confirm the cost with a human, names check_video as the way to collect the result, and provides guidance on when to prefer imageUrl over a text prompt (for logos, products, faces). It also explains how to force a second take by changing the request or passing a new requestId. This is textbook when-to-use and when-not-to-use guidance.

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