> ## Documentation Index
> Fetch the complete documentation index at: https://documentation.uponai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Subagent Node

> Have a conversation with the user while allowing the agent to call tools and functions during the conversation.

Subagent node is used to have a conversation with the user while allowing the agent to call tools / functions during the conversation. Use it when the agent should decide whether and when to use a tool / function based on the conversation context.

<Note>
  If you only need dialogue without tool calling, use a Conversation Node instead.
</Note>

## How It Works

When a subagent node has tools / functions attached, the LLM receives both the node instruction and the list of available tools / functions. During the conversation, the LLM determines when a tool / function should be called based on context, extracts the required parameters, and invokes it while maintaining the dialogue with the user.

* Multiple tools / functions can be added to a single subagent node
* The agent can continue talking while a tool / function executes
* Tool / function results are available to the LLM for generating follow-up responses

## Write Instruction

Subagent nodes only support **Prompt** instructions. Static Sentence is not supported.

Write the instruction to define the task, what information the agent should gather, and when it should use the available tools / functions.

```txt theme={null}
Help the user check their order status. If the user provides an order number,
use the available order lookup tool to retrieve the latest status.
```

## Subagent Node vs Function Node

|                | Function Node                                               | Subagent Node                                                              |
| -------------- | ----------------------------------------------------------- | -------------------------------------------------------------------------- |
| Execution      | Deterministic — executes on node entry                      | LLM-driven — called when LLM decides it's appropriate                      |
| Tools per node | One                                                         | Multiple                                                                   |
| Conversation   | Not intended for dialogue                                   | Full dialogue with tools available                                         |
| Best for       | Always-execute actions (e.g. always look up order on entry) | Context-dependent actions during dialogue (e.g. look up only if user asks) |

## Add Tools / Functions

<Steps>
  <Step title="Select a subagent node">
    Click on a subagent node to open its settings panel on the right side.
  </Step>

  <Step title="Add a tool / function">
    In the settings panel, find the **Tools** section and click **+ Add**. Select the tool / function type from the dropdown.
  </Step>

  <Step title="Configure the tool / function">
    Configure based on its type. See the Available Tool / Function Types table below.
  </Step>

  <Step title="Update the node instruction">
    Update the node prompt to guide the LLM on when to use each tool / function.
  </Step>
</Steps>

## Available Tool / Function Types

| Tool Type                   | Description                                             |
| --------------------------- | ------------------------------------------------------- |
| Custom Function             | Make HTTP requests to your external APIs                |
| Code Tool                   | Run JavaScript code directly without an external server |
| Check Calendar Availability | Query available time slots via Cal.com                  |
| Book Appointment            | Book calendar events via Cal.com                        |
| End Call                    | Terminate the call                                      |
| Transfer Call               | Transfer to a phone number                              |
| Transfer Agent              | Transfer to another agent                               |
| Press Digit                 | Send DTMF tones                                         |
| Send SMS                    | Send a text message                                     |
| Extract Dynamic Variable    | Extract variables from the conversation                 |
| MCP Tool                    | Call tools on your MCP server                           |

## Execution Speech Settings

### Speak During Execution

When enabled, the agent says a message while the tool / function is executing (e.g. "One moment, let me check that for you."). Recommended when the tool / function takes over 1 second including network latency.

Configure how the message is generated:

* **Prompt**: LLM dynamically generates what to say based on a description you provide
* **Static Sentence**: Agent speaks the exact text you provide

### Speak After Execution

When enabled, the agent calls the LLM after the tool / function returns a result so it can speak about the outcome. Turn this off to run the tool silently.

* **Speak During Execution** available on: Custom Function, Code Tool, End Call, Transfer Call, Transfer Agent, MCP Tool
* **Speak After Execution** available on: Custom Function, Code Tool, MCP Tool

## When Can Transition Happen

* When user is done speaking
* When **Skip Response** is enabled and agent finishes speaking

Tool / function execution happens within the subagent node, so the node can stay active across multiple turns and tool / function calls before it transitions.

## Node Settings

| Setting              | Description                                                                                         |
| -------------------- | --------------------------------------------------------------------------------------------------- |
| Tools                | Attach the tools / functions this subagent can use during the conversation.                         |
| Skip Response        | When enabled, only one outgoing edge is allowed. Agent transitions via that edge when done talking. |
| Knowledge Base       | Configure node-level knowledge bases to combine with the agent-level knowledge base.                |
| Global Node          | See Global Node guide.                                                                              |
| Block Interruptions  | When enabled, agent will not be interrupted by user when speaking.                                  |
| LLM                  | Choose a different model — used for response generation, tool selection, and argument generation.   |
| Fine-tuning Examples | Fine-tune conversation response and transition. See Finetune Examples guide.                        |

## Best Practices

* **Be explicit in your node instruction** — tell the agent when each tool / function should be used
* **Use function nodes for guaranteed execution** — if a tool must always run at a certain point, use a function node instead
* **Avoid adding too many tools to one subagent node** — if you have many tools, consider splitting them across multiple subagent nodes