Extract the title generation from the runtime

Signed-off-by: Djordje Lukic <djordje.lukic@docker.com>

Author: rumpl

e2e/runtime_test.go

@@ -31,8 +31,8 @@ func TestRuntime_OpenAI_Basic(t *testing.T) {
 	require.NoError(t, err)
 
 	response := sess.GetLastAssistantMessageContent()
-	assert.Equal(t, "2 + 2 is equal to 4.", response)
-	assert.Equal(t, "Simple Math Calculation", sess.Title)
+	assert.Equal(t, "2 + 2 equals 4.", response)
+	assert.Equal(t, "Basic Math Question", sess.Title)
 }
 
 func TestRuntime_Mistral_Basic(t *testing.T) {
@@ -55,5 +55,5 @@ func TestRuntime_Mistral_Basic(t *testing.T) {
 
 	response := sess.GetLastAssistantMessageContent()
 	assert.Equal(t, "The sum of 2 + 2 is 4.", response)
-	assert.Equal(t, "Basic Arithmetic: Sum of 2 and 2", sess.Title)
+	assert.Equal(t, "Math Basics: Simple Addition", sess.Title)
 }

e2e/testdata/cassettes/TestRuntime_Mistral_Basic.yaml

@@ -219,12 +219,11 @@ type SessionTitleEvent struct {
 	AgentContext
 }
 
-func SessionTitle(sessionID, title, agentName string) Event {
+func SessionTitle(sessionID, title string) Event {
 	return &SessionTitleEvent{
-		Type:         "session_title",
-		SessionID:    sessionID,
-		Title:        title,
-		AgentContext: AgentContext{AgentName: agentName},
+		Type:      "session_title",
+		SessionID: sessionID,
+		Title:     title,
 	}
 }
 

e2e/testdata/cassettes/TestRuntime_OpenAI_Basic.yaml

@@ -132,7 +132,7 @@ type LocalRuntime struct {
 	elicitationEventsChannel    chan Event             // Current events channel for sending elicitation requests
 	elicitationEventsChannelMux sync.RWMutex           // Protects elicitationEventsChannel
 	ragInitialized              atomic.Bool
-	titleGenerationWg           sync.WaitGroup // Wait group for title generation
+	titleGen                    *titleGenerator
 }
 
 type streamResult struct {
@@ -210,6 +210,13 @@ func New(agents *team.Team, opts ...Opt) (*LocalRuntime, error) {
 		return nil, err
 	}
 
+	model := agents.Model()
+	if model == nil {
+		return nil, errors.New("no model found for the team; ensure at least one agent has a valid model")
+	}
+
+	r.titleGen = newTitleGenerator(model)
+
 	slog.Debug("Creating new runtime", "agent", r.currentAgent, "available_agents", agents.Size())
 
 	return r, nil
@@ -488,8 +495,7 @@ func (r *LocalRuntime) finalizeEventChannel(ctx context.Context, sess *session.S
 
 	telemetry.RecordSessionEnd(ctx)
 
-	// Wait for title generation if it's in progress
-	r.titleGenerationWg.Wait()
+	r.titleGen.Wait()
 }
 
 // RunStream starts the agent's interaction loop and returns a channel of events
@@ -543,7 +549,6 @@ func (r *LocalRuntime) RunStream(ctx context.Context, sess *session.Session) <-c
 			return
 		}
 
-		// Emit toolset information
 		events <- ToolsetInfo(len(agentTools), r.currentAgent)
 
 		messages := sess.GetMessages(a)
@@ -558,9 +563,7 @@ func (r *LocalRuntime) RunStream(ctx context.Context, sess *session.Session) <-c
 		r.registerDefaultTools()
 
 		if sess.Title == "" {
-			r.titleGenerationWg.Go(func() {
-				r.generateSessionTitle(ctx, sess, events)
-			})
+			r.titleGen.Generate(ctx, sess, events)
 		}
 
 		iteration := 0
@@ -1353,72 +1356,6 @@ func (r *LocalRuntime) handleHandoff(_ context.Context, _ *session.Session, tool
 	}, nil
 }
 
-// truncateTitle truncates a title to maxLength characters, adding an ellipsis if needed
-func truncateTitle(title string, maxLength int) string {
-	if len(title) <= maxLength {
-		return title
-	}
-	// Ensure we have room for the ellipsis
-	if maxLength < 3 {
-		return "..."
-	}
-	return title[:maxLength-3] + "..."
-}
-
-// generateSessionTitle generates a title for the session based on the first user message
-func (r *LocalRuntime) generateSessionTitle(ctx context.Context, sess *session.Session, events chan Event) {
-	slog.Debug("Generating title for session", "session_id", sess.ID)
-
-	firstUserMessage := sess.GetLastUserMessageContent()
-	if firstUserMessage == "" {
-		slog.Error("Failed generating session title: no user message found in session", "session_id", sess.ID)
-		events <- SessionTitle(sess.ID, "Untitled", r.currentAgent)
-		return
-	}
-
-	systemPrompt := "You are a helpful AI assistant that generates concise, descriptive titles for conversations. You will be given a conversation history and asked to create a title that captures the main topic."
-	userPrompt := fmt.Sprintf("Based on the following message a user sent to an AI assistant, generate a short, descriptive title (maximum 50 characters) that captures the main topic or purpose of the conversation. Return ONLY the title text, nothing else.\n\nUser message: %s\n\n", firstUserMessage)
-
-	titleModel := provider.CloneWithOptions(
-		ctx,
-		r.CurrentAgent().Model(),
-		options.WithStructuredOutput(nil),
-		options.WithMaxTokens(100),
-		options.WithGeneratingTitle(),
-	)
-	newTeam := team.New(
-		team.WithAgents(agent.New("root", systemPrompt, agent.WithModel(titleModel))),
-	)
-	titleSession := session.New(
-		session.WithUserMessage(userPrompt),
-		session.WithTitle("Generating title..."),
-	)
-
-	titleRuntime, err := New(newTeam, WithSessionCompaction(false))
-	if err != nil {
-		slog.Error("Failed to create title generator runtime", "error", err)
-		return
-	}
-
-	// Run the title generation (this will be a simple back-and-forth)
-	_, err = titleRuntime.Run(ctx, titleSession)
-	if err != nil {
-		slog.Error("Failed to generate session title", "session_id", sess.ID, "error", err)
-		return
-	}
-
-	// Get the generated title from the last assistant message
-	title := titleSession.GetLastAssistantMessageContent()
-	if title == "" {
-		return
-	}
-	// Truncate title to 50 characters with ellipsis if needed
-	title = truncateTitle(title, 50)
-	sess.Title = title
-	slog.Debug("Generated session title", "session_id", sess.ID, "title", title)
-	events <- SessionTitle(sess.ID, title, r.currentAgent)
-}
-
 // Summarize generates a summary for the session based on the conversation history
 func (r *LocalRuntime) Summarize(ctx context.Context, sess *session.Session, events chan Event) {
 	slog.Debug("Generating summary for session", "session_id", sess.ID)

pkg/runtime/event.go

@@ -699,7 +699,7 @@ func TestGetTools_WarningHandling(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			root := agent.New("root", "test", agent.WithToolSets(tt.toolsets...))
+			root := agent.New("root", "test", agent.WithToolSets(tt.toolsets...), agent.WithModel(&mockProvider{}))
 			tm := team.New(team.WithAgents(root))
 			rt, err := New(tm, WithModelStore(mockModelStore{}))
 			require.NoError(t, err)
@@ -769,7 +769,7 @@ func TestSummarize_EmptySession(t *testing.T) {
 
 func TestProcessToolCalls_UnknownTool_NoToolResultMessage(t *testing.T) {
 	// Build a runtime with a simple agent but no tools registered matching the call
-	root := agent.New("root", "You are a test agent")
+	root := agent.New("root", "You are a test agent", agent.WithModel(&mockProvider{}))
 	tm := team.New(team.WithAgents(root))
 
 	rt, err := New(tm, WithSessionCompaction(false), WithModelStore(mockModelStore{}))
@@ -856,66 +856,3 @@ func TestEmitStartupInfo(t *testing.T) {
 	// Should be empty due to deduplication
 	require.Empty(t, collectedEvents2, "EmitStartupInfo should not emit duplicate events")
 }
-
-func TestTruncateTitle(t *testing.T) {
-	tests := []struct {
-		name      string
-		title     string
-		maxLength int
-		expected  string
-	}{
-		{
-			name:      "title shorter than max length",
-			title:     "Short title",
-			maxLength: 50,
-			expected:  "Short title",
-		},
-		{
-			name:      "title exactly at max length",
-			title:     "This is exactly fifty characters in length now.",
-			maxLength: 50,
-			expected:  "This is exactly fifty characters in length now.",
-		},
-		{
-			name:      "title longer than max length",
-			title:     "This is a very long title that exceeds the maximum character limit",
-			maxLength: 50,
-			expected:  "This is a very long title that exceeds the maxi...",
-		},
-		{
-			name:      "very short max length",
-			title:     "Any title",
-			maxLength: 5,
-			expected:  "An...",
-		},
-		{
-			name:      "max length less than 3",
-			title:     "Any title",
-			maxLength: 2,
-			expected:  "...",
-		},
-		{
-			name:      "empty title",
-			title:     "",
-			maxLength: 50,
-			expected:  "",
-		},
-		{
-			name:      "title with unicode characters",
-			title:     "こんにちは、これは日本語のタイトルです。とても長いタイトルなので切り捨てられるはずです。",
-			maxLength: 50,
-			expected:  "こんにちは、これは日本語のタイトルです。とても長いタイトルなので切り捨てられるはずです。"[:47] + "...",
-		},
-	}
-
-	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
-			result := truncateTitle(tt.title, tt.maxLength)
-			require.Equal(t, tt.expected, result)
-			// Only check length constraint if maxLength >= 3 (otherwise ellipsis alone is 3 chars)
-			if tt.maxLength >= 3 {
-				require.LessOrEqual(t, len(result), tt.maxLength)
-			}
-		})
-	}
-}

pkg/runtime/runtime.go

@@ -0,0 +1,89 @@
+package runtime
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"sync"
+
+	"github.com/docker/cagent/pkg/agent"
+	"github.com/docker/cagent/pkg/model/provider"
+	"github.com/docker/cagent/pkg/model/provider/options"
+	"github.com/docker/cagent/pkg/session"
+	"github.com/docker/cagent/pkg/team"
+)
+
+const (
+	titleSystemPrompt     = "You are a helpful AI assistant that generates concise, descriptive titles for conversations. You will be given a conversation history and asked to create a title that captures the main topic."
+	titleUserPromptFormat = "Based on the following message a user sent to an AI assistant, generate a short, descriptive title (maximum 50 characters) that captures the main topic or purpose of the conversation. Return ONLY the title text, nothing else.\n\nUser message: %s\n\n"
+)
+
+type titleGenerator struct {
+	wg    sync.WaitGroup
+	model provider.Provider
+}
+
+func newTitleGenerator(model provider.Provider) *titleGenerator {
+	return &titleGenerator{
+		model: model,
+	}
+}
+
+func (t *titleGenerator) Generate(ctx context.Context, sess *session.Session, events chan<- Event) {
+	t.wg.Go(func() {
+		t.generate(ctx, sess, events)
+	})
+}
+
+func (t *titleGenerator) Wait() {
+	t.wg.Wait()
+}
+
+func (t *titleGenerator) generate(ctx context.Context, sess *session.Session, events chan<- Event) {
+	slog.Debug("Generating title for session", "session_id", sess.ID)
+
+	firstUserMessage := sess.GetLastUserMessageContent()
+	if firstUserMessage == "" {
+		return
+	}
+
+	userPrompt := fmt.Sprintf(titleUserPromptFormat, firstUserMessage)
+
+	titleModel := provider.CloneWithOptions(
+		ctx,
+		t.model,
+		options.WithStructuredOutput(nil),
+		options.WithMaxTokens(20),
+		options.WithGeneratingTitle(),
+	)
+
+	newTeam := team.New(
+		team.WithAgents(agent.New("root", titleSystemPrompt, agent.WithModel(titleModel))),
+	)
+
+	titleSession := session.New(
+		session.WithUserMessage(userPrompt),
+		session.WithTitle("Generating title..."),
+	)
+
+	titleRuntime, err := New(newTeam, WithSessionCompaction(false))
+	if err != nil {
+		slog.Error("Failed to create title generator runtime", "error", err)
+		return
+	}
+
+	_, err = titleRuntime.Run(ctx, titleSession)
+	if err != nil {
+		slog.Error("Failed to generate session title", "session_id", sess.ID, "error", err)
+		return
+	}
+
+	title := titleSession.GetLastAssistantMessageContent()
+	if title == "" {
+		return
+	}
+
+	sess.Title = title
+	slog.Debug("Generated session title", "session_id", sess.ID, "title", title)
+	events <- SessionTitle(sess.ID, title)
+}

pkg/runtime/runtime_test.go

@@ -9,6 +9,7 @@ import (
 	"strings"
 
 	"github.com/docker/cagent/pkg/agent"
+	"github.com/docker/cagent/pkg/model/provider"
 	"github.com/docker/cagent/pkg/rag"
 )
 
@@ -66,6 +67,21 @@ func (t *Team) Agent(name string) (*agent.Agent, error) {
 	return found, nil
 }
 
+func (t *Team) Model() provider.Provider {
+	root, err := t.Agent("root")
+	if err == nil {
+		return root.Model()
+	}
+
+	for _, agentName := range t.AgentNames() {
+		a, err := t.Agent(agentName)
+		if err == nil {
+			return a.Model()
+		}
+	}
+	return nil
+}
+
 func (t *Team) Size() int {
 	return len(t.agents)
 }