Animate a cel's scale across frames with adjustable easing and a fixed anchor point.
Scale a source cel across frames with easing and a stable anchor.
| Name | Required | Description | Default |
|---|---|---|---|
| anchor | No | center | |
| easing | No | smoothstep | |
| replace | No | ||
| filename | Yes | ||
| end_frame | Yes | ||
| end_scale | Yes | ||
| layer_name | Yes | ||
| start_frame | Yes | ||
| start_scale | Yes | ||
| source_frame_index | No | ||
| create_missing_cels | No |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It does add the useful detail that the anchor is stable, but it omits significant behavior such as replace=true and create_missing_cels=true defaults, and never states that existing cels in the range may be overwritten.
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, front-loaded sentence with no filler. Every word contributes meaning and the core intent is immediately clear.
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, 6 required, no annotations, and no output schema, a one-line description is not enough. An agent would have to infer frame-range semantics, scaling units, optional flag behavior, and overwrite consequences, which is too much for a mutating tween operation.
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% across 11 parameters, and the description only loosely maps to easing and anchor. It does not explain units for start_scale/end_scale, the meaning of source_frame_index, or the behavior controlled by replace and create_missing_cels.
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 states a specific verb ('Scale'), a specific resource ('a source cel'), and the scope ('across frames'), while also naming two distinguishing modifiers: 'easing' and 'a stable anchor.' This is enough for an agent to tell it apart from sibling position/opacity tween tools without opening the schema.
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 phrase 'across frames with easing' clearly implies the intended use case: tweening a cel's scale over a frame range with easing. It does not explicitly route away from sibling tools like tween_cel_positions_eased or tween_cel_opacity_eased, so it falls short of a 5.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.