genai_get_role
This page explains how to use the genai_get_role function in APL.
The genai_get_role function retrieves the role of a message at a specific position in a GenAI messages array. This allows you to understand who sent a particular message in the conversation (user, assistant, system, tool, etc.).
You can use this function to validate conversation structure, analyze message patterns, verify conversation flow, or process conversations based on role sequences.
Usage
Syntax
genai_get_role(messages, index)Parameters
| Name | Type | Required | Description |
|---|---|---|---|
| messages | dynamic | Yes | An array of message objects from a GenAI conversation. Each message typically contains role and content fields. |
| index | long | Yes | The zero-based position of the message whose role you want to retrieve. Use 0 for the first message, 1 for the second, etc. |
Returns
Returns a string containing the role of the message at the specified index (such as 'user', 'assistant', 'system', 'tool', 'function'), or an empty string if the index is out of bounds.
Example
Get the role of the first message in a GenAI conversation.
Query
['otel-demo-genai']
| extend first_role = genai_get_role(['attributes.gen_ai.input.messages'], 0)
| summarize conversations_with_system = countif(first_role == 'system'), total_conversations = count()Output
| conversations_with_system | total_conversations |
|---|---|
| 1250 | 1450 |
This query verifies that most conversations are properly initialized with system prompts.
List of related functions
- genai_get_content_by_index: Gets content at a specific index. Combine with genai_get_role to understand both role and content at positions.
- genai_message_roles: Lists all roles in the conversation. Use this to get a complete picture of all roles rather than checking individual positions.
- genai_get_content_by_role: Gets content filtered by role. Use this when you need content from a specific role type.
- array_length: Returns the total number of messages. Use this to validate index bounds before accessing positions.