streaming

Streaming Example

Real-time response streaming with the PromptKit SDK.

What You'll Learn

• Using Stream() for real-time responses
• Processing chunks as they arrive
• Handling stream completion and errors
• Progress tracking during generation

Prerequisites

• Go 1.26+
• An API key for one of: OpenAI, Anthropic, or Google

Running the Example

The pack does not name a provider — the SDK detects one from the environment, so any of these works:

export OPENAI_API_KEY=your-key       # uses gpt-4o
# or
export ANTHROPIC_API_KEY=your-key
# or
export GOOGLE_API_KEY=your-key

go run .

Code Overview

conv, err := sdk.Open("./streaming.pack.json", "storyteller")
if err != nil {
    log.Fatal(err)
}
defer conv.Close()

ctx := context.Background()

// Stream responses in real-time
for chunk := range conv.Stream(ctx, "Tell me a short story") {
    if chunk.Error != nil {
        log.Printf("Error: %v", chunk.Error)
        break
    }
    if chunk.Type == sdk.ChunkDone {
        fmt.Println("\n[Complete]")
        break
    }
    // Print text as it arrives
    fmt.Print(chunk.Text)
}

Chunk Types

const (
    ChunkText     // Text content arrived
    ChunkToolCall // Tool is being called
    ChunkDone     // Stream completed
)

Pack File Structure

The streaming.pack.json defines:

• Prompt: A creative storyteller with higher temperature

It deliberately does not pin a provider, so the example runs against whichever of OpenAI / Anthropic / Google you have a key for.

{
  "prompts": {
    "storyteller": {
      "system_template": "You are a creative storyteller...",
      "parameters": {
        "temperature": 0.9,
        "max_tokens": 500
      }
    }
  }
}

Progress Tracking

Track generation progress while streaming:

var charCount int

for chunk := range conv.Stream(ctx, "Tell me about AI") {
    if chunk.Type == sdk.ChunkDone {
        fmt.Printf("\n[Complete - %d characters]\n", charCount)
        break
    }
    fmt.Print(chunk.Text)
    charCount += len(chunk.Text)
}

Key Concepts

1. Channel-Based - Stream() returns a channel of chunks
2. Non-Blocking - Print responses as they arrive
3. Error Handling - Check chunk.Error for issues
4. Completion - ChunkDone signals end of stream

Next Steps

• Hello Example - Basic conversation
• Tools Example - Function calling
• HITL Example - Human-in-the-loop approval