Render an animation to a WebM video

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

With no annotations, the description carries the behavioral disclosure burden. It reveals implementation details (canvas.captureStream, MediaRecorder, VP9 fallback) and default duration logic. However, it omits important behavior such as return value, whether it writes to disk, browser/headless environment requirements, and whether existing files are overwritten.

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 two sentences, front-loaded with the core purpose, and every clause adds value (format, method, codec, default duration). 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?

The tool has 10 parameters, no annotations, and no output schema. The description explains core function and duration default but does not cover width/height/artboard/animation/stateMachine semantics, output naming, or return value. For the complexity, the description is incomplete and would leave an agent guessing about half the parameters.

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 only 50%, so the description must compensate for the five undocumented parameters (width, height, artboard, animation, stateMachine). It adds meaning only for 'duration' by explaining default one-loop behavior and the 2s fallback. No explanation is given for the other undocumented parameters, leaving the agent without sufficient guidance.

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 clearly states the verb 'Render' and the resource '.riv animation (or state machine)' with a specific output format 'WebM video'. It distinguishes from sibling render tools (gif, apng, frame) by explicitly naming the container format and capture technique.

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 implies usage for creating WebM videos when a real-time recording is needed, and clarifies default duration behavior. However, it does not explicitly mention when to use this tool over alternatives like riv_render_gif or riv_render_frame, nor does it provide exclusions or prerequisites.

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