registry

name	registry
description	Look up UE5 material-graph node types in node_registry.yaml and add missing ones. Invoke before generating YAML when you hit an unfamiliar expression class (e.g. ComponentMask, Fresnel, CustomRotator) or when the user asks whether a node or Material Function is already registered. This is the authoritative catalogue of node shapes the clipboard-mode generator can emit.

UE5 Node Registry Manager

This skill checks if a node type exists in node_registry.yaml and creates it if missing.

Registry Location

../../node_registry.yaml

(Relative to this skill's base directory -- at the plugin root.)

When to Use

ALWAYS check the registry BEFORE generating shader YAML when:

• User mentions a node type you're unsure about
• You need a node that might not be in the registry
• User asks for a specific UE5 node by name

Workflow

1. Check if node exists in registry
2. If missing, determine the node specification:
   • Expression class name
   • Input pins (names, categories)
   • Output pins
   • Default properties
3. Add to ../../node_registry.yaml
4. Confirm the node is now available

How to Determine Node Specification

Method 1: From UE5 Documentation

Look up the MaterialExpression class in UE5 docs to find:

• Input/output pin names
• Property names and defaults

Method 2: From User's Existing Nodes

Ask the user to copy-paste an example of the node from their material.

Method 3: Common Patterns

Most nodes follow patterns:

• Single input -> Single output (Abs, Floor, Saturate)
• Two inputs A,B -> Single output (Add, Multiply, Dot)
• Special inputs (Lerp: A, B, Alpha)

Node Definition Format

NodeTypeName:
  expression_class: MaterialExpressionNodeTypeName
  inputs:
    - name: InputName
      category: required|optional
      pin_name: "Display Name"  # optional, if different from name
  outputs:
    - name: Output
      subcategory: ""  # or "red", "green", "blue", "alpha", "mask"
  properties:
    DefaultProperty: value
  property_mappings:
    yaml_key: UE5PropertyName  # maps simple YAML keys to UE5 property names

Common Node Patterns

Single Input Node (like Abs, Floor, Saturate)

NodeName:
  expression_class: MaterialExpressionNodeName
  inputs:
    - name: Input
      category: required
  outputs:
    - name: Output

Two Input Node (like Add, Multiply)

NodeName:
  expression_class: MaterialExpressionNodeName
  inputs:
    - name: A
      category: optional
    - name: B
      category: optional
  outputs:
    - name: Output
  properties:
    ConstA: 0.0
    ConstB: 1.0

Coordinate Node (like TexCoord, ScreenPosition)

NodeName:
  expression_class: MaterialExpressionNodeName
  outputs:
    - name: Output
  properties:
    SomeDefault: value

Procedure

When invoked with a node type name:

Step 1: Read Current Registry

Read ../../node_registry.yaml

Step 2: Check if Node Exists

• If exists: Report "Node type X is available" with its definition
• If missing: Proceed to Step 3

Step 3: Determine Specification

Ask user or use known patterns:

• What is the expression class? (Usually MaterialExpression + NodeName)
• What inputs does it have?
• What outputs?
• Any default properties?

Step 4: Add to Registry

Append the new node definition to ../../node_registry.yaml

Step 5: Confirm

Report the new node is available and show example usage.

Examples of Nodes to Add

Fresnel

Fresnel:
  expression_class: MaterialExpressionFresnel
  inputs:
    - name: ExponentIn
      category: optional
    - name: BaseReflectFractionIn
      category: optional
    - name: Normal
      category: optional
  outputs:
    - name: Output
  properties:
    Exponent: 5.0
    BaseReflectFraction: 0.04

SphereMask

SphereMask:
  expression_class: MaterialExpressionSphereMask
  inputs:
    - name: A
      category: required
    - name: B
      category: required
    - name: Radius
      category: optional
    - name: Hardness
      category: optional
  outputs:
    - name: Output
  properties:
    AttenuationRadius: 256.0
    HardnessPercent: 100.0

Output Format

When checking a node, respond with:

If exists:

Node type "Multiply" exists in registry.

Definition:
  expression_class: MaterialExpressionMultiply
  inputs: A (optional), B (optional)
  outputs: Output
  properties: ConstA=0.0, ConstB=1.0

Example usage in YAML:
  - name: MyMultiply
    type: Multiply
    const_a: 2.0

If missing and added:

Node type "Fresnel" not found in registry.

Adding to node_registry.yaml...

Added definition:
  expression_class: MaterialExpressionFresnel
  inputs: ExponentIn (optional), BaseReflectFractionIn (optional), Normal (optional)
  outputs: Output
  properties: Exponent=5.0, BaseReflectFraction=0.04

Node type "Fresnel" is now available.

Example usage in YAML:
  - name: MyFresnel
    type: Fresnel
    properties:
      Exponent: 3.0