System Prompt

Define EVI’s behavior, responses, and style.

A system prompt in the context of EVI is a set of instructions that shape the AI’s behavior, responses, and overall style during a chat session. It defines the specific goal or role for EVI—for example, acting as a customer support representative, a fitness coach, or a travel advisor—ensuring that the conversation aligns with your application’s intended focus.

Default system prompt

If you do not specify a system prompt in your configuration, EVI will automatically use a default system prompt. You can review our default system prompt for reference.

Building your system prompt

Prompts are managed as resources within our API and are version controlled. This enables you to:

  • Develop and refine system prompts over time.
  • Maintain consistent behavior across chat sessions.
  • Reuse and reference existing prompts in different configurations.

For tips and best practices on creating effective system prompts, please refer to our Prompting Guide.

While the Platform UI is the recommended interface for building your EVI configurations, should you require a programmatic interface, prompts can also be created programmatically through our API. See our API Reference for more details.

Specifying a system prompt in your configuration

When creating a configuration, you have two options for defining the system prompt:

  1. Reference an existing prompt: Specify the ID of a pre-existing, version-controlled Prompt. EVI will use the referenced prompt in the chat session.

    Specifying an existing prompt
    1curl -X POST https://api.hume.ai/v0/evi/configs \
    2  -H "X-Hume-Api-Key: <apiKey>" \
    3  -H "Content-Type: application/json" \
    4  -d '{
    5    "evi_version": "2",
    6    "name": "Sample Config",
    7    "prompt": {
    8      "id": "af699d45-2985-42cc-91b9-af9e5da3bac5",
    9      "version": 0
    10    }
    11  }'

  2. Define a new Prompt in the request: Provide the prompt text directly in your configuration request. In this case, a new prompt will be automatically created and associated with the configuration.

    Specifying an existing prompt
    1curl -X POST https://api.hume.ai/v0/evi/configs \
    2  -H "X-Hume-Api-Key: <apiKey>" \
    3  -H "Content-Type: application/json" \
    4  -d '{
    5    "evi_version": "2",
    6    "name": "Sample Config",
    7    "prompt": {
    8      "text": "Sample system prompt"
    9    }
    10  }'

See our API reference for details on how to specify system prompts in your EVI configuration.

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