h3_reference_to_video

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

With no annotations, the description discloses key behaviors: the job is asynchronous ('Returns immediately with a prompt_id - poll job_status'), it takes minutes with an estimated_seconds field, and ref_image_size 'max' is 'several times slower.' It also warns about sage_attention redundancy. It doesn't cover permissions or failure modes, but the disclosure is strong for a generation tool.

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 dense single paragraph where every sentence adds value: purpose, syntax, limits, parameter trade-offs, use case, timing, and async behavior. While long, it is justified by complexity. Structure could be improved with bullets, but it is not wasteful.

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 a 17-parameter tool with no annotations and no output schema, the description covers the critical invocation details: async flow, reference syntax, parameter trade-offs, and the cross-shot workflow. It doesn't explicitly say references are asset IDs from list_assets, but the sibling context implies it. Overall, sufficient for correct use.

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?

Despite 0% schema coverage, the description explains the most important parameters: positional refs in prompt, max counts for ref arrays, ref_image_size trade-offs, width/height defaults, and sage_attention. It omits steps, scheduler, megapixels, and shift_* but these are secondary with defaults. The compensation is solid but not exhaustive.

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: 'Generate video with synchronized audio from a prompt plus reference images, videos, and/or audio.' It also explicitly identifies this as the tool for 'CONSISTENCY ACROSS SHOTS,' which distinguishes it from the sibling h3_image_to_video. The positional reference syntax and model name add further specificity.

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 provides a concrete use case workflow: generate shot 1, pull a frame, and pass it as a reference for subsequent shots. It also gives guidance on leaving width/height unset and checking list_assets before setting sage_attention. It does not explicitly contrast with h3_image_to_video, but the cross-shot scenario clearly implies when this tool is appropriate.

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