Set Variables

Overview

The Set Variables node writes one or more named values into the workflow's shared variable scope, making them accessible to downstream nodes by reference. Use it to initialize counters, store intermediate results, build dynamic strings, or pass computed values across branches without hardcoding them in each node. Variables set here follow workflow-scoped lifetime — they persist for the duration of the run but are not persisted to external storage. Values can be static literals or expressions referencing upstream node outputs.

Configuration

Field	Type	Required	Description
variables	array of objects	Yes	List of variable assignments. Each entry has a name (string, the variable key) and a value (any scalar or expression). Names must be unique within the node; duplicates are resolved in order (last wins).
variables[].name	string	Yes	The variable key written into workflow scope. Must be a valid identifier (alphanumeric and underscores, no spaces). Referenced downstream as {{variables.name}}.
variables[].value	string	number	boolean
variables[].overwrite	boolean	No	When false, skips assignment if the variable already exists in scope. Defaults to true. Useful for setting defaults early in a workflow without clobbering values set by earlier branches.

Inputs

Port	Type	Description
input	any	Trigger signal and upstream execution context. The node reads this context to resolve any expression-based variable values before writing to scope.

Outputs

Port	Type	Description
output	any	Passes the incoming execution context downstream, augmented with the newly set variables. The original payload is forwarded unchanged; variable writes are side-effects on workflow scope.

Example

{
  "nodeType": "set_variables",
  "config": {
    "variables": [
      {
        "name": "round_limit",
        "value": 3,
        "overwrite": false
      },
      {
        "name": "judge_model",
        "value": "gpt-4o",
        "overwrite": true
      },
      {
        "name": "battle_label",
        "value": "{{nodes.config_fetch.output.label}}",
        "overwrite": true
      }
    ]
  }
}