---
title: "Action fastline_pro"
description: "Sends a request to a Fast Line Pro agent and stores the response in a constant."
---

# Action `fastline_pro`

> **System ID:** `action_fastline_pro`

## Description

Talks to a **Fast Line Pro** agent: sends a request, keeps conversation context via a constant, optionally files (vision), and blocking / streaming modes. The agent’s model and tools are set in the Fast Line Pro UI (Publish), not in the node JSON.

The response is stored in a constant (`completion` or `save_response`).

## Events (scenario branches)

| Event | When it occurs |
|-------|----------------|
| *(response text)* | Success: the action returns the agent’s response text |
| **error** | Missing `agent_name` / request / token, timeout, or service error |

On success the branch is **the response text itself**. For stable branching use the `save_response` constant and the **error** branch.

## Parameters

| Parameter | Type | Required | Default | Description |
|-----------|------|----------|---------|-------------|
| `agent_name` | string | yes | — | Fast Line Pro agent name |
| `user_input` | string | no | message text | User request. Supports placeholders |
| `conversation_id` | string | no | `null` | **Constant name** where the conversation ID is stored (not the ID itself) |
| `reset_conversation` | string | no | — | If truthy — clears the conversation constant and starts a new one |
| `inputs` | object | no | `{}` | Extra variables for the agent |
| `user` | string | no | current `chat_id` | User identifier for the agent |
| `mode` | string | no | `"blocking"` | `blocking` or `agent` (streaming) |
| `timeout_seconds` | number | no | `30` | Timeout for streaming mode |
| `vision_file` | boolean | no | `false` | Process attached images/files |
| `save_response` | string | no | `"completion"` | Constant for the response |

## Configuration example

```json
{
  "agent_name": "customer_support",
  "user_input": "{{user_question}}",
  "conversation_id": "fl_pro_conversation",
  "mode": "blocking",
  "timeout_seconds": 30,
  "save_response": "completion"
}
```

## Related docs

- [Actions reference](/en/actionjail/reference/actions-reference.md)