System Messages

Overview

The SystemMessageInterceptor modifies incoming requests to include custom system messages. This interceptor works with chat-format requests, replacing any existing system messages with the configured message.

Tip

Add Request Logging Interceptor to your interceptor chain to verify if your requests are modified correctly.

Configuration

CLI Configuration

--overrides 'target.api_endpoint.adapter_config.use_system_prompt=True,target.api_endpoint.adapter_config.custom_system_prompt="You are a helpful assistant."'

YAML Configuration

target:
  api_endpoint:
    adapter_config:
      interceptors:
        - name: system_message
          config:
            system_message: "You are a helpful AI assistant."
        - name: "endpoint"
          enabled: true
          config: {}

Configuration Options

Parameter	Description	Type	Required
system_message	System message to add to requests	str	Yes

Behavior

The interceptor modifies chat-format requests by:

1. Removing any existing system messages from the messages array

2. Inserting the configured system message as the first message

3. Preserving all other request parameters

Example Request Transformation

# Original request
{
    "messages": [
        {"role": "user", "content": "What is 2+2?"}
    ]
}

# After system message interceptor
{
    "messages": [
        {"role": "system", "content": "You are a helpful AI assistant."},
        {"role": "user", "content": "What is 2+2?"}
    ]
}

If an existing system message is present, the interceptor replaces it:

# Original request with existing system message
{
    "messages": [
        {"role": "system", "content": "Old system message"},
        {"role": "user", "content": "What is 2+2?"}
    ]
}

# After system message interceptor
{
    "messages": [
        {"role": "system", "content": "You are a helpful AI assistant."},
        {"role": "user", "content": "What is 2+2?"}
    ]
}