Subgraph Node

The Subgraph node allows embedding another workflow graph into the current workflow, enabling process reuse and modular design. Subgraphs can come from external YAML files or be defined inline in the configuration.

Configuration

Field	Type	Required	Default	Description
`type`	string	Yes	-	Subgraph source type: `file` or `config`
`config`	object	Yes	-	Contains different configurations depending on `type`

File Type Configuration

Field	Type	Required	Description
`path`	string	Yes	Subgraph file path (relative to `yaml_instance/` or absolute path)

Config Type Configuration

Inline definition of the complete subgraph structure, containing the same fields as the top-level graph:

Field	Type	Required	Description
`id`	string	Yes	Subgraph identifier
`description`	string	No	Subgraph description
`log_level`	string	No	Log level (DEBUG/INFO)
`nodes`	list	Yes	Node list
`edges`	list	No	Edge list
`start`	list	No	Entry node list
`end`	list	No	Exit node list
`memory`	list	No	Memory definitions specific to the subgraph

Core Concepts

Modular Reuse

Extract commonly used process fragments into independent YAML files that can be reused by multiple workflows:

Example: Package an "article polishing" process as a subgraph
Different main workflows can call this subgraph

Variable Inheritance

Subgraphs inherit vars variable definitions from the parent graph, supporting cross-level variable passing.

Execution Isolation

Subgraphs execute as independent units with their own:

Node namespace
Log level configuration
Memory definitions (optional)

When to Use

Process reuse: Multiple workflows sharing the same sub-processes
Modular design: Breaking complex processes into manageable smaller units
Team collaboration: Different teams maintaining different subgraph modules

Examples

Referencing External File

yaml

nodes:
  - id: Review Process
    type: subgraph
    config:
      type: file
      config:
        path: common/review_flow.yaml

Inline Subgraph Definition

yaml

nodes:
  - id: Translation Unit
    type: subgraph
    config:
      type: config
      config:
        id: translation_subgraph
        description: Multi-language translation subprocess
        nodes:
          - id: Translator
            type: agent
            config:
              provider: openai
              name: gpt-4o
              role: You are a professional translator who translates content to the target language.
          - id: Proofreader
            type: agent
            config:
              provider: openai
              name: gpt-4o
              role: You are a proofreading expert who checks and polishes translated content.
        edges:
          - from: Translator
            to: Proofreader
        start: [Translator]
        end: [Proofreader]

Combining Multiple Subgraphs

yaml

nodes:
  - id: Input Handler
    type: agent
    config:
      provider: openai
      name: gpt-4o

  - id: Analysis Module
    type: subgraph
    config:
      type: file
      config:
        path: modules/analysis.yaml

  - id: Report Module
    type: subgraph
    config:
      type: file
      config:
        path: modules/report_gen.yaml

edges:
  - from: Input Handler
    to: Analysis Module
  - from: Analysis Module
    to: Report Module

Notes

Subgraph file paths support relative paths (based on yaml_instance/) and absolute paths
Avoid circular nesting (A references B, B references A)
The subgraph's start and end nodes determine how data flows in and out, which decides how the subgraph processes messages from the parent graph and which node's final output is returned to the parent graph