Sub-workflow

The sub-workflow trigger turns a workflow into a function: other workflows call it (via the call workflow action step or an agent tool), it runs with the caller's data, and its final output returns to the caller.

When it runs

When any workflow in the workspace invokes it. The callee must be active.

Config

One switch: pass the caller's payload through, or start clean.

• Pass payload through — on: the caller's payload becomes this workflow's starting payload. Off: starts with {}.

Output

The caller's payload (with pass-through on) — whatever shape the calling step sent. Document your own contract: sub-workflows are easiest to reuse when they expect a small, named set of fields.

Patterns

• Shared delivery — one "notify team" workflow every other workflow calls, so changing the channel is one edit.
• Agent tools — an AI agent step can call a sub-workflow as a tool, turning any workflow into a capability the model can use.
• Decomposition — a big pipeline split into testable parts.

Gotchas

• Call depth is bounded — a sub-workflow calling itself (or a cycle of callers) stops at the limit instead of recursing forever.
• The caller waits synchronously for the result — keep sub-workflows quick or the parent run inherits the wait.