Configuring EVI
Guide to configuring the Empathic Voice Interface (EVI).
The Empathic Voice Interface (EVI) is designed to be highly configurable, allowing developers to customize the interface to align with their specific requirements. Configuration of EVI can be managed through two primary methods: an EVI configuration and session settings.
Configuration options
EVI configuration options affect the behavior and capabilities of the interface, and include the following configuration options:
Configs, as well as system prompts and tools, are versioned. This versioning system supports iterative development, allowing you to progressively refine configurations and revert to previous versions if needed.
Default configuration options
EVI is pre-configured with a set of default values, which are automatically applied if you do not specify a configuration. The default configuration includes a preset voice and language model, but does not include a system prompt or tools. To customize these options, you will need to create and specify your own EVI configuration.
The default configuration settings are as follows:
Default configuration settings are subject to change. To ensure your setup remains consistent should changes occur, we recommend choosing explicit options when defining your EVI configuration.
Create a configuration
See instructions below for creating an EVI configuration through the Portal. In the Portal, navigate to the EVI Configurations page. Click the Create configuration button to begin.
Choose EVI version
To learn more about the differences between EVI versions 1 and 2, please see the feature comparison guide.
Choose voice
Select a voice from Hume’s 8 presets, or create your own custom voice. To learn more about voice customization options on the Hume Platform, please visit the Voices page.
Add tools
Equip EVI with built-in tools, like web search, or custom user-defined tools. Click the + Add button to select an existing tool or create a new one.
Test the configuration
The newly created configuration can now be tested. From the EVI Config details page, click Run in playground to test it out.
Once in the EVI Playground, click Start call to connect to EVI with your configuration.
The event message and timeout configuration options are not part of the initial config creation flow. However, you can set these options at any time in the playground or from the configuration’s edit page after your configuration has been created.
Apply the configuration
After creating an EVI configuration, you can use it in your conversations with EVI by including the config_id
in the query parameters of your connection request. You can find the config_id
on the configuration’s edit page. To access this page, first navigate to the configurations page
and then click the Edit button for the desired configuration.
See the sample code below which showcases how to apply your configuration:
Session settings
EVI configurations are persistent and version-controlled. In contrast, session settings are temporary and apply only to the current session, such as microphone settings. These parameters can be adjusted dynamically based on the requirements of each session to ensure optimal performance and user experience.
Refer to the API reference for detailed descriptions of the various session settings options.
Updating the session settings is only a requirement when the audio input is encoded in PCM Linear 16. If this is the case, be sure to send the following Session Settings message prior to sending an audio input:
Dynamic variables
EVI can reference and update session-specific values as a conversation progresses. By including dynamic variables in the system prompt, you can personalize conversations with EVI.
Visit our prompting guide for more details on adding dynamic variables to your prompt.
To use this feature, first define a variables parameter within a Session Settings message containing one or more dynamic variables.
Each key-value pair in "variables"
must have a string key representing the variable name and a string value.
For example, you can define the user’s name
and set it to a default value:
Then, include the variable surrounded by two pairs of curly braces, such as {{name}}
, as a placeholder value in your system prompt:
To ensure your dynamic variables are recognized properly, confirm the following:
- If you have defined a dynamic variable, reference it.: If the variable is defined but not referenced in the system prompt, then it will not be included in the conversation and EVI will not be able to refer to the variable.
- If you have referenced a dynamic variable, make sure it is defined.: If the variable is referenced in the system prompt, but it is not defined in the
"variables"
field, then the warningW0106
will be raised: “No values have been specified for the variables [variable_name] which can lead to incorrect text formatting. Please assign them values.” For example, this error can occur when there are spelling mistakes or differences between the variable defined in the"variables"
field and the variable referenced in the system prompt (i.e.{{firstName}}
instead of{{name}}
).