overlays_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 behavioral disclosure. It describes key behaviors like looping the overlay video until the background ends and trimming extra frames, which are valuable beyond basic function. However, it lacks details on permissions, error handling, or performance aspects (e.g., processing time, file size limits).

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 well-structured and front-loaded with the core functionality, followed by organized parameter and return sections. Every sentence earns its place by explaining behavior, parameters, or outputs without redundancy, making it efficient and easy to parse.

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 tool's complexity (6 parameters, video processing) and no annotations, the description is mostly complete: it explains the operation, all parameters, and the return value. With an output schema present, it need not detail return values further. A slight gap exists in not covering edge cases or prerequisites (e.g., supported video formats).

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 provides a clear Args section explaining all 6 parameters with meaningful semantics (e.g., 'Path to background video', 'Where to place overlay'), adding value beyond the schema's minimal titles. However, it could enhance details like scale units or positioning specifics beyond the enum.

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 tool's purpose with specific verbs ('overlay a video on top of another') and resources ('video'), distinguishing it from siblings like 'overlay_image' (which handles images) and 'clip_video' (which trims videos). It explicitly mentions the looping behavior and trimming of extra frames, providing unique functional details.

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 video overlays with positioning and scaling, but does not explicitly state when to use this tool versus alternatives like 'overlay_image' (for images) or 'concat_clips_with_transition' (for concatenation). It provides clear context for video compositing tasks but lacks explicit exclusions or named alternatives.

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