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Merge

The Merge component combines outputs from multiple upstream branches into a single value. It is the fan-in counterpart to branching patterns -- use it after parallel paths to bring results back together.

Property Value
Component Type merge
Category Logic
Display Name Merge

Ports

Inputs

Port Data Type Required Description
branches ARRAY Yes Outputs from multiple upstream nodes

Outputs

Port Data Type Description
merged ANY Combined result from all branches

Configuration

The Merge component accepts the following configuration in extra_config:

Field Type Default Description
mode string append Merge strategy: append or combine
source_nodes array -- Explicit list of node IDs to merge (optional)

Merge modes

Mode Behavior Output Type
append Collects all source outputs into a flat array. Lists are flattened, scalar values are appended as individual items. Array
combine Merges all source outputs into a single object. Each dict source is merged via update(). Non-dict sources are keyed by an auto-generated ID. Object

Usage

  1. Add a Merge node from the Node Palette (Logic category)
  2. Connect multiple upstream nodes to the Merge node's input
  3. Optionally set the mode and source_nodes in Extra Config
  4. Connect the Merge node's output to downstream nodes

Source resolution

If source_nodes is specified, only outputs from those node IDs are merged. If not specified, all available node outputs in the workflow state are included.

Example

Two agents process input in parallel, and their outputs are merged before being sent to a final summarizer:

flowchart LR
    T[Chat Trigger] --> A1[Research Agent]
    T --> A2[Analysis Agent]
    A1 --> MG[Merge]
    A2 --> MG
    MG --> S[Summary Agent]

Merge Extra Config (append mode):

{
  "mode": "append",
  "source_nodes": ["agent_research", "agent_analysis"]
}

Output:

{
  "merged": [
    "Research findings: The market grew 15% in Q4...",
    "Analysis conclusion: Growth is driven by..."
  ]
}

Merge Extra Config (combine mode):

{
  "mode": "combine",
  "source_nodes": ["agent_research", "agent_analysis"]
}

Output:

{
  "merged": {
    "output": "Analysis conclusion: Growth is driven by...",
    "research_data": "..."
  }
}

Combine mode key collisions

In combine mode, if multiple source nodes produce dicts with the same keys, later sources overwrite earlier ones. Use append mode if you need to preserve all values, or ensure source nodes use distinct output keys.