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

# Types of Session Variables

Session variables in your flow can be categorized into several types based on how they are created and managed.

## Capture Variables

Capture Variables are automatically captured by the Agent during execution based on the description you provide. The Agent identifies and stores relevant information as the workflow progresses.

## Tool-Returned Capture Variables

These variables are returned by tools during execution, including both custom and predefined tools.

For custom tools, simply return the variables in the `capture_variables` dictionary, and they will be automatically stored as session variables(each key stored as seperate session variable).

## User Variables

User Variables are defined in the API payload before executing an autonomous or conversational flow. These allow you to pass initial data into your workflow.

## System Variables

The following system variables are automatically set in every session:

* **`workflow_id`** - A unique identifier assigned to each workflow execution
* **`caller_number`** - Available during voice calls, containing the caller's phone number
* `conversation_history` - Available throughout the particular workflow execution

## Predefined Tool Variables

When using predefined tools, the entire output object returned by the tool is saved as a session variable.

### Example: Telegram Tool

<img src="https://mintcdn.com/phinite/spbPnSZPWmAXAKhH/images/Screenshot2026-02-11at6.40.01PM.png?fit=max&auto=format&n=spbPnSZPWmAXAKhH&q=85&s=41e2cf412dcc47e8fbcc8c4e006beec8" alt="Screenshot 2026 02 11 At 6 40 01 PM" title="Screenshot 2026 02 11 At 6 40 01 PM" style={{ width:"41%" }} width="484" height="332" data-path="images/Screenshot2026-02-11at6.40.01PM.png" />

For the `telegram.get_chat_member_count` tool (from the Telegram integration), the complete output object is stored in the session and can be accessed using dot notation:

```python theme={null}
telegram.get_chat_member_count.count
telegram.get_chat_member_count.chat_id
```

### Using in Custom Tools

You can access these variables in your custom tools like this:

```python theme={null}
# Retrieve the entire output object
telegram_output = inputs.get('telegram.get_chat_member_count')

# Access specific fields
chat_id = telegram_output.get("chat_id")
member_count = telegram_output.get("count")
```

<Note>
  The session variable name follows the pattern: `{tool_name}.{subtool_name}`
</Note>