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YAML schema reference for Semantic Kernel prompts

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The YAML schema reference for Semantic Kernel prompts is a detailed reference for YAML prompts that lists all supported YAML syntax and their available options.

Definitions

name

The function name to use by default when creating prompt functions using this configuration. If the name is null or empty, a random name will be generated dynamically when creating a function.

description

The function description to use by default when creating prompt functions using this configuration.

template_format

The identifier of the Semantic Kernel template format. Semantic Kernel provides support for the following template formats:

  1. semantic-kernel - Built-in Semantic Kernel format.
  2. handlebars - Handlebars template format.
  3. liquid - Liquid template format

template

The prompt template string that defines the prompt.

input_variables

The collection of input variables used by the prompt template. Each input variable has the following properties:

  1. name - The name of the variable.
  2. description - The description of the variable.
  3. default - An optional default value for the variable.
  4. is_required - Whether the variable is considered required (rather than optional). Default is true.
  5. json_schema - An optional JSON Schema describing this variable.
  6. allow_dangerously_set_content - A boolean value indicating whether to handle the variable value as potential dangerous content. Default is false. See Protecting against Prompt Injection Attacks for more information.

Tip

The default for allow_dangerously_set_content is false. When set to true the value of the input variable is treated as safe content. For prompts which are being used with a chat completion service this should be set to false to protect against prompt injection attacks. When using other AI services e.g. Text-To-Image this can be set to true to allow for more complex prompts.

output_variable

The output variable used by the prompt template. The output variable has the following properties:

  1. description - The description of the variable.
  2. json_schema - The JSON Schema describing this variable.

execution_settings

The collection of execution settings used by the prompt template. The execution settings are a dictionary which is keyed by the service ID, or default for the default execution settings. The service id of each PromptExecutionSettings must match the key in the dictionary.

Each entry has the following properties:

  1. service_id - This identifies the service these settings are configured for e.g., azure_openai_eastus, openai, ollama, huggingface, etc.
  2. model_id - This identifies the AI model these settings are configured for e.g., gpt-4, gpt-3.5-turbo.
  3. function_choice_behavior - The behavior defining the way functions are chosen by LLM and how they are invoked by AI connectors. For more information see Function Choice Behaviors

Tip

If provided, the service identifier will be the key in a dictionary collection of execution settings. If not provided the service identifier will be set to default.

Function Choice Behavior

To disable function calling, and have the model only generate a user-facing message, set the property to null (the default).

  • auto - To allow the model to decide whether to call the functions and, if so, which ones to call.
  • required - To force the model to always call one or more functions.
  • none - To instruct the model to not call any functions and only generate a user-facing message.

allow_dangerously_set_content

A boolean value indicating whether to allow potentially dangerous content to be inserted into the prompt from functions. The default is false. When set to true the return values from functions only are treated as safe content. For prompts which are being used with a chat completion service this should be set to false to protect against prompt injection attacks. When using other AI services e.g. Text-To-Image this can be set to true to allow for more complex prompts. See Protecting against Prompt Injection Attacks for more information.

Sample YAML prompt

Below is a sample YAML prompt that uses the Handlebars template format and is configured with different temperatures when be used with gpt-3 and gpt-4 models.

name: GenerateStory
template: |
  Tell a story about {{topic}} that is {{length}} sentences long.
template_format: handlebars
description: A function that generates a story about a topic.
input_variables:
  - name: topic
    description: The topic of the story.
    is_required: true
  - name: length
    description: The number of sentences in the story.
    is_required: true
output_variable:
  description: The generated story.
execution_settings:
  service1:  
    model_id: gpt-4
    temperature: 0.6
  service2:
    model_id: gpt-3
    temperature: 0.4
  default:
    temperature: 0.5

Next steps

Handlebars Prompt Templates Liquid Prompt Templates