Set node

The Set node copies a value into a new variable — either lifting a value out of an existing reference or storing a fixed literal. It's how you give a value a stable, well-named home so later nodes can read it cleanly.

Component id: flowrunner/set.

How it works

Set reads a source and writes it under a variable name. The engine decides between two modes by looking at the source string:

• Reference copy — if the source contains a dot and the part before the first dot is a namespace that exists in refs, Set copies refs[namespace][field] into the new variable.
• Literal — otherwise the source is treated as a literal string, with ${env.X} and ${secrets.X} resolved first.

The engine splits the reference on the first dot only: start.email reads the email field from the start namespace. (A deeper path like start.user.name would look for a field literally called user.name, so Set works best for top-level fields — use a Template node for nested paths.)

How the value is stored

• If the resolved value is a plain object, it's stored as-is — read its fields with variable.field.
• If it's a scalar (string, number, boolean) or an array, it's wrapped as { value: <the value> } — read it back with variable.value.

Config

Field	Required	Description
var	No (default value)	The name of the variable to create.
source	Yes	Either a dotted reference (start.email) to copy, or a literal string. Literals resolve ${env.X} / ${secrets.X}.

Ports

Set has a single next port. It only fails if something unexpected throws — in which case an unhandled failure surfaces as an error, or routes to a wired error port.

Examples

Copy a request field into a clearly-named variable:

Set  var: chosen   source: start.email
# → refs.chosen = { value: "a@b.com" }
# read later as: chosen.value

Store a fixed literal (useful for tagging a branch):

Set  var: tier   source: premium
# → refs.tier = { value: "premium" }

Pull a value in from a secret:

Set  var: apiBase   source: ${env.API_BASE_URL}
# → refs.apiBase = { value: "https://api.example.com" }

TIP

Copying an object source (like a whole start bucket) preserves its shape, so you can read variable.field directly. Scalar and literal sources are always wrapped, so remember the extra .value.

See also

• Template node
• ForEach node
• Secrets
• Node reference overview