feat: add streaming output for CLI

- Add streamWriter to LLMAgent for real-time output
- Support streaming mode in chatWithToolLoop
- Add SetStreamWriter to Kernel and LLMAgent
- CLI displays streaming responses immediately
- Tool calling still works with streaming

cmd/orca/main.go

@@ -43,6 +43,8 @@ func main() {
 		log.Fatalf("Failed to start kernel: %v", err)
 	}
 
+	k.SetStreamWriter(os.Stdout)
+
 	fmt.Println("Orca Agent Framework")
 	fmt.Println("Kernel started successfully")
 	fmt.Printf("  LLM Model: %s\n", cfg.Ollama.Model)
@@ -76,15 +78,13 @@ func main() {
 				continue
 			}
 
-			// Send message to LLM agent via kernel
-			response, err := k.SendMessage("user", "llm", input)
-			if err != nil {
-				fmt.Printf("Error: %v\n", err)
-				continue
-			}
-
-			fmt.Println(response)
-			fmt.Println()
+		// Send message to LLM agent via kernel
+		_, err := k.SendMessage("user", "llm", input)
+		if err != nil {
+			fmt.Printf("Error: %v\n", err)
+			continue
+		}
+		fmt.Println()
 		}
 
 		if err := scanner.Err(); err != nil {

pkg/actor/llm_agent.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"io"
 	"strings"
 
 	"github.com/orca/orca/pkg/bus"
@@ -20,12 +21,13 @@ import (
 // back to the LLM for final response generation.
 type LLMAgent struct {
 	*BaseAgent
-	llm          llm.LLM
-	sessionMgr   *session.Manager
-	sessionID    string
-	toolManager  *tool.Manager
-	toolWorker   *ToolWorker
-	windowSize   int
+	llm           llm.LLM
+	sessionMgr    *session.Manager
+	sessionID     string
+	toolManager   *tool.Manager
+	toolWorker    *ToolWorker
+	windowSize    int
+	streamWriter  io.Writer
 }
 
 // LLMAgentOption is a functional option for configuring the LLMAgent.
@@ -66,6 +68,13 @@ func WithWindowSize(size int) LLMAgentOption {
 	}
 }
 
+// WithStreamWriter sets the writer for streaming LLM output.
+func WithStreamWriter(w io.Writer) LLMAgentOption {
+	return func(a *LLMAgent) {
+		a.streamWriter = w
+	}
+}
+
 // NewLLMAgent creates a new LLMAgent with the given LLM backend and options.
 // The agent is started automatically upon creation.
 func NewLLMAgent(id string, backend llm.LLM, opts ...LLMAgentOption) *LLMAgent {
@@ -218,23 +227,26 @@ func (a *LLMAgent) chatWithToolLoop(ctx context.Context, messages []llm.Message)
 	maxRounds := 10
 
 	for round := 0; round < maxRounds; round++ {
-		response, err := a.llm.Chat(ctx, messages)
+		var content string
+		var err error
+
+		if a.streamWriter != nil {
+			content, err = a.streamChat(ctx, messages)
+		} else {
+			content, err = a.syncChat(ctx, messages)
+		}
 		if err != nil {
 			return "", fmt.Errorf("chat round %d failed: %w", round, err)
 		}
 
-		toolCalls := response.ToolCalls
+		toolCalls := a.parseToolCallsFromContent(content)
 		if len(toolCalls) == 0 {
-			toolCalls = a.parseToolCallsFromContent(response.Content)
-		}
-
-		if len(toolCalls) == 0 {
-			return response.Content, nil
+			return content, nil
 		}
 
 		messages = append(messages, llm.Message{
 			Role:    "assistant",
-			Content: response.Content,
+			Content: content,
 		})
 
 		for _, tc := range toolCalls {
@@ -249,6 +261,42 @@ func (a *LLMAgent) chatWithToolLoop(ctx context.Context, messages []llm.Message)
 	return "", fmt.Errorf("llm_agent: exceeded maximum tool call rounds (%d)", maxRounds)
 }
 
+func (a *LLMAgent) syncChat(ctx context.Context, messages []llm.Message) (string, error) {
+	response, err := a.llm.Chat(ctx, messages)
+	if err != nil {
+		return "", err
+	}
+
+	if len(response.ToolCalls) > 0 {
+		return response.Content, nil
+	}
+	return response.Content, nil
+}
+
+func (a *LLMAgent) streamChat(ctx context.Context, messages []llm.Message) (string, error) {
+	var content strings.Builder
+	if a.streamWriter != nil {
+		fmt.Fprint(a.streamWriter, "\n")
+	}
+
+	err := a.llm.Stream(ctx, messages, func(chunk string) error {
+		content.WriteString(chunk)
+		if a.streamWriter != nil {
+			fmt.Fprint(a.streamWriter, chunk)
+		}
+		return nil
+	})
+
+	if err != nil {
+		return "", err
+	}
+
+	if a.streamWriter != nil {
+		fmt.Fprintln(a.streamWriter)
+	}
+	return content.String(), nil
+}
+
 func (a *LLMAgent) parseToolCallsFromContent(content string) []llm.ToolCall {
 	var parsed struct {
 		Tool      string                 `json:"tool"`
@@ -333,6 +381,9 @@ func (a *LLMAgent) handleSystem(ctx context.Context, msg bus.Message) (bus.Messa
 	}, nil
 }
 
-// Compile-time interface checks.
+func (a *LLMAgent) SetStreamWriter(w io.Writer) {
+	a.streamWriter = w
+}
+
 var _ Agent = (*LLMAgent)(nil)
 var _ Agent = (*ToolWorker)(nil)

pkg/kernel/kernel.go

@@ -7,6 +7,7 @@ package kernel
 import (
 	"context"
 	"fmt"
+	"io"
 	"log"
 	"os"
 	"sync"
@@ -228,6 +229,13 @@ func (k *Kernel) LLMAgent() *actor.LLMAgent {
 	return k.llmAgent
 }
 
+// SetStreamWriter sets the writer for streaming LLM output.
+func (k *Kernel) SetStreamWriter(w io.Writer) {
+	if k.llmAgent != nil {
+		k.llmAgent.SetStreamWriter(w)
+	}
+}
+
 // SendMessage sends a message from a source to the LLM agent.
 //
 // This is the primary public API for interacting with the Orca system.