capcut_add_mask

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

No annotations are provided, so the description carries the burden. It discloses the destructive replacement of an existing mask and specifies fraction ranges for several parameters. However, it does not mention potential side effects, permission requirements, or what happens if the segment lacks a mask, leaving some gaps.

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?

A single sentence that is front-loaded with the primary action and includes the critical note about fraction ranges. Every word earns its place; no fluff.

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?

With 11 parameters, no output schema, and no annotations, the description is sparse. It covers the core action and some parameter types but omits return behavior, error handling, and detailed semantics for many parameters, making it incomplete for confident invocation.

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 explains that several parameters (center/width/height/rotation/feather/roundCorner) are fractions, and names the source for 'name', but it leaves draft, segmentId, invert, centerX, centerY, and others undefined. Given 11 parameters, this is insufficient.

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 function: attaching a mask shape to a segment, explicitly referencing the source (capcut_list_masks) and the replacement behavior. This distinguishes it from sibling tools like add_filter or add_transition, which have different purposes.

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 indicates when to use the tool (to attach a mask) and that it replaces existing masks, but does not explicitly mention when not to use it or alternatives (e.g., for adjusting mask properties, use set_props). The context is clear but lacks exclusions.

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