This example demonstrates the Variable Providers feature in PromptKit SDK, which allows dynamic injection of variables into prompts at runtime.

Features Demonstrated

1. TimeProvider - Built-in provider that injects current time/date variables
2. Custom Provider - Creating your own provider for application-specific context
3. Automatic Resolution - Variables are resolved before each Send() call

Running the Example

export OPENAI_API_KEY=your-key
cd sdk/examples/variables
go run .

How It Works

1. Create Providers

// Built-in time provider
timeProvider := variables.NewTimeProviderWithLocation(time.Local)

// Custom provider for user context
userProvider := NewUserContextProvider("user-12345")

2. Add to Conversation

conv, err := sdk.Open("./assistant.pack.json", "assistant",
    sdk.WithVariableProvider(timeProvider),
    sdk.WithVariableProvider(userProvider),
)

3. Variables Auto-Inject

Each time you call conv.Send(), all providers are queried and their variables are merged into the template context:

// TimeProvider provides: current_time, current_date, current_weekday, etc.
// UserContextProvider provides: user_id, user_language, response_style, etc.
resp, err := conv.Send(ctx, "What time is it?")

Creating Custom Providers

Implement the variables.Provider interface:

type Provider interface {
    Name() string
    Provide(ctx context.Context) (map[string]string, error)
}

Example:

type MyProvider struct {
    // your fields
}

func (p *MyProvider) Name() string {
    return "my_provider"
}

func (p *MyProvider) Provide(ctx context.Context) (map[string]string, error) {
    // Fetch data from database, API, cache, etc.
    return map[string]string{
        "my_variable": "my_value",
    }, nil
}

Available Built-in Providers

Use Cases

• Personalization: Inject user preferences, language, timezone
• Context Awareness: Current time, location, session data
• A/B Testing: Inject experiment variants
• Multi-tenancy: Inject tenant-specific configuration
• External Data: Fetch real-time data from APIs/databases