Change a layer's blend mode in an After Effects composition to control how it composites with underlying layers. Specify the composition, layer, and desired blend mode.
Set the blending mode of a layer
| Name | Required | Description | Default |
|---|---|---|---|
| comp_name | Yes | Composition name | |
| blend_mode | Yes | Blend mode name | |
| layer_name | Yes | Layer name |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the burden of behavioral disclosure. 'Set' implies mutation, but it does not state whether the operation overwrites existing blend modes, what happens if the composition or layer is missing, whether the change is undoable, or what the return value indicates.
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, front-loaded sentence states the action and target clearly with zero wasted words. It is appropriately sized for a simple setter.
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?
The tool is relatively simple, and the schema covers all parameters including the blend_mode enum. However, with no output schema and no behavioral details, the description leaves an agent without expectations about failure modes, side effects, or success criteria.
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 100%, so the parameters are already fully documented. The description adds no additional parameter semantics; baseline 3 is appropriate because the schema does the heavy lifting.
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 uses a specific verb ('Set') and a specific resource/attribute ('blend mode of a layer'), clearly identifying the tool's function. It does not explicitly differentiate from the sibling ae_set_layer_property, but the named attribute makes the purpose unambiguous.
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?
No guidance is given on when to use this tool instead of alternatives such as ae_set_layer_property or other layer setters. The only usage implication is the tautological one—use it to set a blend mode—which provides no decision support.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.