---
title: "Set Node Parameters"
description: "Reference for Set (action_set, custom_modules__set) node parameters in Node Inspector — setting variables, placeholders, mathematical expressions."
---

# Set Node Parameters

The **Set** node (`action_set`, `custom_modules__set`) sets or modifies variables (constants) for later use in the scenario. Values can be static, from placeholders, or from mathematical expressions. In **Node Inspector** (right panel) configuration is set as a JSON object.

## Format

- **Key** — variable name (e.g., `param1`, `counter`, `client_name`).
- **Value** — text, placeholder, or expression:
  - **Text** — string in quotes.
  - **Placeholder** — `{{variable_name}}` (value from previous nodes).
  - **Mathematical expression** — e.g., `{{param1}}+2`, `{{count}}*10`.

## Examples

**Static value:**
```json
{
  "greeting": "Welcome!",
  "max_retries": 3
}
```

**With placeholder:**
```json
{
  "client_name": "{{outputVariable}}",
  "summary": "Client {{client_name}} selected category {{category}}"
}
```

**Mathematical expression:**
```json
{
  "counter": "{{counter}}+1",
  "total": "{{price}}*{{quantity}}"
}
```

## Placeholders

- Variables from **Wait for Input**, **Message with Buttons**, **Slider** nodes, etc. are supported.
- Syntax: `{{outputVariable}}` or `{{variable_name}}`.
- Variables set in Set are available in subsequent scenario nodes.

**Tip:** Set does not send messages to the client — it only changes the scenario execution context.

---

## Related Documents

- [Create scenario](/en/scenariobuilder/how-to/create-scenario.md)
- [Use action in scenario](/en/scenariobuilder/how-to/use-action-in-scenario.md)
- [Scenario editor overview](/en/scenariobuilder/explanation/what-is-scenario-editor.md)
- [Actions reference — Set](/en/actionjail/reference/actions-reference.md) — detailed description of `action_set` and `custom_modules__set`