capcut_apply_mask

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

With no annotations provided, the description must disclose behavioral context, but it only states that a mask is applied with certain options. It does not clarify whether an existing mask is replaced, whether the mask applies only to video segments or also images/text, or what side effects occur on the timeline. This is a significant transparency gap for a mutation 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 a single sentence that front-loads the action and resource, then lists the selectable mask shapes and key effects. There is no redundant or filler content, making it concise 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?

This is an 11-parameter editing operation with no output schema and no annotations, yet the description provides only a terse one-line summary. It omits critical context such as which segment types are eligible, whether the mask replaces an existing mask, and what the expected result is, so the tool is not fully specified for an agent making a selection decision.

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 91%, so the schema already documents most parameters in detail. The description adds little beyond restating feather and inversion, so the baseline score of 3 is appropriate; the description does not need to compensate for parameter meaning.

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 identifies the operation as applying a video shape mask and enumerates the supported mask types along with feather and inversion, making the tool's purpose unmistakable. The verb 'Apply' plus the specific resource 'video shape mask' distinguishes it from sibling tools like capcut_apply_effect and capcut_apply_transition without requiring schema inspection.

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 guidance about when to use a shape mask versus related operations such as chroma key, effects, or animations, nor any indication of limitations or alternatives. The intended use case is only implied by the tool name and mask-type list, leaving the agent to infer selection context.

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