reference_to_video

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

With no annotations, the description carries the full behavioral burden, and it only discloses return values (task id, status, output URLs). It omits that the call is asynchronous, that wait=true (the default) blocks until a terminal status, that timeouts/poll intervals are configurable, and that the provider validates and may reject remote reference files.

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 short sentences with the core action and return shape front-loaded and no filler. It is tight but arguably too terse for a 12-parameter, async, no-annotation tool.

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 12-parameter async generation tool with no annotations and no output schema, the description leaves out the polling/wait semantics, validation failure behavior, and two undocumented params. Mentioning the return fields is a partial offset, but an agent cannot call this correctly without additional assumptions.

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 83%, so the schema already documents most parameters (audio, aspect_ratio, reference URLs with their limits, callback_url, etc.). The description adds nothing beyond that, and two parameters (timeout_ms, poll_interval_ms) are undocumented in both places. Baseline 3 applies.

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 (Create), resource (a Vidu task on RunAPI), and modality (reference to video), which implicitly separates it from the sibling image_to_video. It never names the sibling explicitly, so the differentiation relies on the reader parsing 'reference' vs 'image'.

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?

There is no when-to-use guidance, no condition for choosing this over image_to_video, and no mention that reference_image_urls is mandatory or what happens when reference images conflict with the prompt. The agent gets no routing help from the description.

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