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

# genai_extract_system_prompt

> This page explains how to use the genai_extract_system_prompt function in APL.

The `genai_extract_system_prompt` function extracts the system prompt from a GenAI messages array. The system prompt typically contains instructions that define the AI assistant’s behavior, personality, and capabilities. It’s usually the first message with role 'system'.

You can use this function to audit AI behavior configurations, monitor prompt changes, analyze consistency across conversations, or validate that correct system instructions are being used.

## For users of other query languages

If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.

<AccordionGroup>
  <Accordion title="Splunk SPL users">
    In Splunk SPL, you would need to filter messages by role and extract the first system message.

    <CodeGroup>
      ```sql Splunk example theme={null}
      | eval system_msgs=mvfilter(match(role, "system"))
      | eval system_prompt=mvindex(system_msgs, 0)
      ```

      ```kusto APL equivalent theme={null}
      ['ai-logs']
      | extend system_prompt = genai_extract_system_prompt(messages)
      ```
    </CodeGroup>
  </Accordion>

  <Accordion title="ANSI SQL users">
    In ANSI SQL, you would unnest the array and filter for the first system role message.

    <CodeGroup>
      ```sql SQL example theme={null}
      SELECT 
        conversation_id,
        content as system_prompt
      FROM (
        SELECT *, ROW_NUMBER() OVER (PARTITION BY conversation_id ORDER BY msg_index) as rn
        FROM conversations
        CROSS JOIN UNNEST(messages) WITH OFFSET AS msg_index
        WHERE role = 'system'
      ) WHERE rn = 1
      ```

      ```kusto APL equivalent theme={null}
      ['ai-logs']
      | extend system_prompt = genai_extract_system_prompt(messages)
      ```
    </CodeGroup>
  </Accordion>
</AccordionGroup>

## Usage

### Syntax

```kusto theme={null}
genai_extract_system_prompt(messages)
```

### 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. |

### Returns

Returns a string containing the content of the system message, or an empty string if no system message is found.

## Example

Extract the system prompt from a GenAI conversation to verify AI configuration.

**Query**

```kusto theme={null}
['otel-demo-genai']
| extend system_prompt = genai_extract_system_prompt(['attributes.gen_ai.input.messages'])
| where isnotempty(system_prompt)
| summarize conversation_count = count() by system_prompt
| top 3 by conversation_count
```

[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B%27otel-demo-genai%27%5D%20%7C%20extend%20system_prompt%20%3D%20genai_extract_system_prompt\(%5B%27attributes.gen_ai.input.messages%27%5D\)%20%7C%20where%20isnotempty\(system_prompt\)%20%7C%20summarize%20conversation_count%20%3D%20count\(\)%20by%20system_prompt%20%7C%20top%203%20by%20conversation_count%22%7D)

**Output**

| system\_prompt                                                               | conversation\_count |
| ---------------------------------------------------------------------------- | ------------------- |
| You are a helpful customer service assistant.                                | 1250                |
| You are a technical support expert specializing in software troubleshooting. | 845                 |

This query helps you understand which system prompts are most commonly used and track prompt variations.

## List of related functions

* [genai\_extract\_user\_prompt](/apl/scalar-functions/genai-functions/genai-extract-user-prompt): Extracts the user's prompt. Use this to analyze what users are asking, while system prompts define AI behavior.
* [genai\_extract\_assistant\_response](/apl/scalar-functions/genai-functions/genai-extract-assistant-response): Extracts the assistant's response. Use this to see how the AI responded based on the system prompt.
* [genai\_get\_content\_by\_role](/apl/scalar-functions/genai-functions/genai-get-content-by-role): Gets content by any role. Use this for more flexible extraction when you need other specific roles.
* [genai\_message\_roles](/apl/scalar-functions/genai-functions/genai-message-roles): Lists all message roles. Use this to understand conversation structure and verify system message presence.