n8n Connections

n8n's SDK has a small connection grammar. Two of its shapes silently produce broken workflows that pass validation. This skill is mostly about not falling into those traps.

The non-negotiable: the .to() trap

.to() must go inside .add(), not after.

.add(node.output(0)).to(target)      // ❌ connection silently dropped
.add(node.output(0).to(target))      // ✅

validate_workflow does not catch this. The workflow validates, publishes, and runs without the wire. The bug looks identical to a misconfigured or "not firing" node.

If you've written .add(...).to(...) outside the parens, you have a bug. No exceptions.