Interface IPromptTemplate

Namespace

AiDotNet.Interfaces

Assembly

AiDotNet.dll

Defines the contract for prompt templates used in language model interactions.

public interface IPromptTemplate

Remarks

A prompt template provides a structured way to create prompts for language models by combining a template string with runtime variables. Templates support variable substitution, formatting, and composition of complex prompts from reusable components.

For Beginners: A prompt template is like a form with blanks to fill in.

Think of it like a mad lib:

• Template: "The {adjective} {noun} {verb} over the {place}."
• Variables: adjective="quick", noun="fox", verb="jumped", place="fence"
• Result: "The quick fox jumped over the fence."

In LLM applications:

• Template: "Translate the following {source_lang} to {target_lang}: {text}"
• Variables: source_lang="English", target_lang="French", text="Hello"
• Result: "Translate the following English to French: Hello"

Benefits of using templates:

• Reusability: Write the template once, use it many times
• Consistency: All prompts have the same structure
• Maintainability: Change the template in one place
• Safety: Validate inputs before insertion
• Clarity: Separate prompt logic from data

Properties

InputVariables

Gets the list of variable names that this template expects.

IReadOnlyList<string> InputVariables { get; }

Property Value

IReadOnlyList<string>

Remarks

Returns the names of all variables that should be provided when formatting the template. This allows validation and introspection of template requirements.

For Beginners: This tells you what blanks need to be filled in.

Example: Template: "Convert {amount} {from_currency} to {to_currency}" InputVariables: ["amount", "from_currency", "to_currency"]

This is helpful for:

• Validation: Check if you have all required variables before formatting
• Documentation: See what inputs a template needs
• UI generation: Automatically create input forms
• Error prevention: Catch missing variables early

Template

Gets the raw template string before variable substitution.

string Template { get; }

Property Value

string

Remarks

The template string defines the structure of the prompt with placeholders for variables. Placeholders are typically denoted with curly braces, e.g., {variable_name}.

For Beginners: This is the original template with the placeholders.

Example: Template: "Explain {concept} to a {audience} in {style} language."

You can inspect the template to:

• See the prompt structure
• Debug issues
• Create variations
• Document your system

Methods

Format(Dictionary<string, string>)

Formats the template with the provided variables to create a complete prompt.

string Format(Dictionary<string, string> variables)

Parameters

variables Dictionary<string, string>

Dictionary of variable names and their values.

Returns

string

The formatted prompt string.

Remarks

This method takes a dictionary of variables and substitutes them into the template to produce the final prompt string. Variable names in the template are typically enclosed in curly braces like {variable_name}.

For Beginners: This fills in the blanks in your template.

Example: Template: "Summarize this article about {topic} in {num_sentences} sentences: {article_text}"

Variables:

• topic: "climate change"
• num_sentences: "3"
• article_text: "Global temperatures are rising..."

Result: "Summarize this article about climate change in 3 sentences: Global temperatures are rising..."

Error handling:

• If a required variable is missing, an exception is thrown
• If extra variables are provided, they're typically ignored
• Variable values are safely inserted (no injection attacks)

Validate(Dictionary<string, string>)

Validates that the provided variables match the template's requirements.

bool Validate(Dictionary<string, string> variables)

Parameters

variables Dictionary<string, string>

Dictionary of variable names and their values.

Returns

bool

True if all required variables are present and valid; otherwise, false.

Remarks

Checks whether the provided variables satisfy the template's requirements, including presence of all required variables and validity of their values.

For Beginners: This checks if you have all the required pieces before formatting.

Example: Template needs: ["question", "context"]

Variables provided: {"question": "What is AI?"} Validate() → False (missing "context")

Variables provided: {"question": "What is AI?", "context": "AI stands for..."} Validate() → True (all required variables present)

This helps you catch errors before sending prompts to the model:

• Prevents runtime errors
• Gives clear error messages
• Ensures prompt quality