Start node

The Start node is the entry point of every flow. Every graph has exactly one Start node; it is the only node that cannot be added, duplicated or deleted.
What it does
When you run a flow, the run input (the JSON you type into the Input panel, the webhook body, or the scheduled input) becomes the payload that the Start node hands to the first connected node.
Configuration
- Description — an optional label describing the flow’s input. Purely documentation; it does not affect execution.
How the input flows
The Start node’s payload is the run input. For example, with run input:
{ "question": "What is Sobmit?" } …an Agent node wired directly to Start can reference it via a template:
Answer the question: {input.question} Example
A minimal flow is just Start → Output. With run input "hello", the Output
node renders "hello".
Most real flows use Start → Agent → Output, where the run input is the
question the Agent answers.
Notes
- The Start node doubles as the run control: click it while idle to start a run, or while running to stop it.
- “Run from here” starts a run at a specific node instead of at Start, seeding the upstream results from a previous run.