Render video

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

With no annotations, the description carries the disclosure burden and does well by explaining determinism, the absence of generation keys, the processing order of clips, burning in overlays/captions, music mixing, and the output asset id. It lacks explicit side-effect or failure-mode details, but these are secondary for a create-and-return 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 two concise, information-dense sentences. It front-loads the primary action and output, then expands with the key processing steps without any filler or redundant content.

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?

Given the complex nested schema and no output schema, the description covers the essential behavior (purpose, process, return value). It does not mention progress checks or failure handling, but the description is complete enough for an agent to select and invoke 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 0%, so the description must compensate. It adds meaning to the sole `plan` parameter by defining it as a 'declarative RenderPlan' and explaining how its components (clips, overlays, captions, music) are processed. It does not enumerate all nested properties like fps, aspect, or quality, but those are present in the 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?

The description clearly states what the tool does: 'Compile a declarative RenderPlan into an mp4 via ffmpeg'. It details the scope with specific processing steps (concatenation, overlays, captions, music) and return value, distinguishing it from siblings like render_carousel.

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?

It gives clear context for when to use it ('deterministic, brand-aware, no generation keys needed') and describes the input ('declarative RenderPlan'). However, it does not explicitly mention alternatives or when not to use this tool (e.g., render_carousel for carousels, generate_video for generative content).

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