n8n-subworkflows

1# n8n Sub-workflows
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3A sub-workflow is a reusable function. An **Execute Workflow Trigger** declares typed inputs, the body does the work, and the last node returns the output. A caller invokes it through an **Execute Workflow** node like any other step.
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5That framing buys you the things functions buy you everywhere: encapsulation, reuse, testability, replaceability. It's the primary reuse mechanism in n8n, and it's badly underused. Without it, the same logic gets copy-pasted across workflows — then a bug gets fixed in two places, the third copy gets missed, and your "identical" copies quietly drift apart.
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7This skill is about when to reach for a sub-workflow, how to define its input/output contract so callers (and agents) can actually use it, how to call it correctly (`all` vs `each`, blocking vs fire-and-forget), and how to name it so it gets found instead of rebuilt.
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9---
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11## The two non-negotiables
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13Everything else is judgement. These two are not.
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15### 1. Search before you build
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17Before you write logic for a generic problem, check whether a sub-workflow already does it. The community MCP can't filter workflows by tag, so the **name is the discovery surface**:
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19```
20n8n_list_workflows()                          # scan the library
21n8n_get_workflow({ id: "<candidate>" })       # read its inputs/outputs + body
22```
23…