add_video_mask

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

With no annotations provided, the description carries full burden for behavioral disclosure. While it documents parameters thoroughly, it doesn't describe what the tool actually does behaviorally: whether it modifies the video segment in-place, creates a new version, requires specific permissions, has side effects, or what the output looks like. '添加蒙版效果' (add mask effect) suggests a mutation but lacks critical behavioral context.

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 appropriately sized but not optimally structured. The purpose statement is clear but brief, followed by a detailed parameter list. While all information is useful, it could be more front-loaded with higher-level context before diving into parameters. The parameter documentation is thorough but makes the description somewhat dense.

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 (10 parameters, mutation operation), no annotations, but with an output schema present, the description does reasonably well. It thoroughly documents all parameters and their semantics. The main gap is lack of behavioral context about what the tool actually does and how it affects the video segment. The output schema existence means return values don't need explanation, but operational behavior is underspecified.

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?

With 0% schema description coverage and 10 parameters, the description provides comprehensive semantic information beyond the bare schema. It explains what each parameter means, provides defaults, valid ranges (feather: 0~100), conditional validity (rect_width/round_corner only for rectangle masks), and references to other tools for obtaining values. This fully compensates for the schema's lack of descriptions.

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 '为视频片段添加蒙版效果' (add mask effect to video segment), which is a specific verb+resource combination. It distinguishes this tool from siblings like add_video_effect or add_video_filter by focusing specifically on masks. However, it doesn't explicitly differentiate mask effects from other visual effects in the sibling list.

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 context through parameter documentation (e.g., video_segment_id comes from add_video_segment, mask_type can be found using find_effects_by_type). However, it lacks explicit guidance on when to use this tool versus alternatives like add_video_effect or add_video_filter, and doesn't mention prerequisites or exclusions.

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