feat: group chats observe context, respond on mention only by default (issue #12)

- Add ObserveOnly flag to bus.InboundMessage
- Add BaseChannel.ObserveGroupMessage (publishes without typing/placeholder)
- Update all 10 channels to call ObserveGroupMessage instead of silently
  dropping non-mention group messages (Telegram, Discord, Slack, Matrix,
  LINE, IRC, OneBot, DingTalk, Feishu, WhatsApp)
- Add agent.observeMessage to store observed messages in session history
  with sender attribution format [DisplayName]: content
- Default group_trigger.mention_only=true for Telegram, Discord, Slack,
  IRC, OneBot, DingTalk, Feishu, QQ (Matrix/LINE already defaulted to true)
- Add GroupTrigger support to WhatsApp native (default MentionOnly=false
  to preserve existing respond-to-all behavior; users can opt-in)
- Add tests for ObserveGroupMessage and observeMessage in loop_test.go

Closes #12

https://claude.ai/code/session_01BEyzHEY8t2ghPnfr5WsSRB

pkg/agent/loop.go

@@ -1372,6 +1372,11 @@ func (al *AgentLoop) processMessage(ctx context.Context, msg bus.InboundMessage)
 		return al.processSystemMessage(ctx, msg)
 	}
 
+	// Observe-only messages are stored in session history but do not trigger a response.
+	if msg.ObserveOnly {
+		return al.observeMessage(ctx, msg)
+	}
+
 	route, agent, routeErr := al.resolveMessageRoute(msg)
 	if routeErr != nil {
 		return "", routeErr
@@ -1432,6 +1437,57 @@ func (al *AgentLoop) processMessage(ctx context.Context, msg bus.InboundMessage)
 	return al.runAgentLoop(ctx, agent, opts)
 }
 
+// observeMessage records an observe-only group message into session history without calling the LLM.
+// It is invoked when a channel publishes a message with ObserveOnly=true (i.e. the bot is not
+// mentioned in mention_only mode). Context is retained so the bot can reference the full
+// conversation when it is later @mentioned.
+func (al *AgentLoop) observeMessage(ctx context.Context, msg bus.InboundMessage) (string, error) {
+	route, agent, err := al.resolveMessageRoute(msg)
+	if err != nil {
+		logger.DebugCF("agent", "observeMessage: failed to resolve route, skipping", map[string]any{
+			"channel": msg.Channel,
+			"error":   err.Error(),
+		})
+		return "", nil
+	}
+
+	sessionKey := resolveScopeKey(route, msg.SessionKey)
+
+	// Attribute the message to its sender so the agent has full context when later mentioned.
+	senderName := msg.Sender.DisplayName
+	if senderName == "" {
+		senderName = msg.SenderID
+	}
+	content := msg.Content
+	if content == "" && len(msg.Media) > 0 {
+		content = "[media]"
+	}
+	if senderName != "" && content != "" {
+		content = fmt.Sprintf("[%s]: %s", senderName, content)
+	}
+
+	if content == "" {
+		return "", nil
+	}
+
+	agent.Sessions.AddMessage(sessionKey, "user", content)
+	if saveErr := agent.Sessions.Save(sessionKey); saveErr != nil {
+		logger.DebugCF("agent", "observeMessage: failed to save session", map[string]any{
+			"session_key": sessionKey,
+			"error":       saveErr.Error(),
+		})
+	}
+
+	logger.DebugCF("agent", "Observed group message (no response)", map[string]any{
+		"channel":     msg.Channel,
+		"session_key": sessionKey,
+		"sender":      senderName,
+		"preview":     utils.Truncate(content, 60),
+	})
+
+	return "", nil
+}
+
 func (al *AgentLoop) resolveMessageRoute(msg bus.InboundMessage) (routing.ResolvedRoute, *AgentInstance, error) {
 	registry := al.GetRegistry()
 	route := registry.ResolveRoute(routing.RouteInput{

pkg/agent/loop_test.go

@@ -3365,3 +3365,131 @@ func TestProcessMessage_ContextOverflow_AnthropicStyle(t *testing.T) {
 		t.Fatalf("expected 2 calls for retry, got %d", provider.calls)
 	}
 }
+
+func TestObserveOnlyMessage_AddsToHistoryWithoutLLMCall(t *testing.T) {
+	tmpDir := t.TempDir()
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				Workspace:         tmpDir,
+				ModelName:         "test-model",
+				MaxTokens:         4096,
+				MaxToolIterations: 10,
+			},
+		},
+		Session: config.SessionConfig{
+			DMScope: "per-channel-peer",
+		},
+	}
+
+	msgBus := bus.NewMessageBus()
+	provider := &countingMockProvider{response: "LLM reply"}
+	al := NewAgentLoop(cfg, msgBus, provider)
+
+	observeMsg := bus.InboundMessage{
+		Channel:  "telegram",
+		SenderID: "telegram:user1",
+		Sender: bus.SenderInfo{
+			Platform:    "telegram",
+			PlatformID:  "user1",
+			CanonicalID: "telegram:user1",
+			DisplayName: "Alice",
+		},
+		ChatID:      "group42",
+		Content:     "we should meet at 3pm",
+		Peer:        bus.Peer{Kind: "group", ID: "group42"},
+		ObserveOnly: true,
+	}
+
+	// Compute session key before processing
+	route := al.registry.ResolveRoute(routing.RouteInput{
+		Channel: observeMsg.Channel,
+		Peer:    extractPeer(observeMsg),
+	})
+	sessionKey := route.SessionKey
+
+	_, err := al.processMessage(context.Background(), observeMsg)
+	if err != nil {
+		t.Fatalf("processMessage() error = %v", err)
+	}
+
+	// LLM must NOT have been called for an observe-only message
+	if provider.calls != 0 {
+		t.Fatalf("expected 0 LLM calls for observe-only message, got %d", provider.calls)
+	}
+
+	// No outbound response should have been sent
+	select {
+	case msg := <-msgBus.OutboundChan():
+		t.Fatalf("expected no outbound message for observe-only, got %+v", msg)
+	default:
+	}
+
+	// The message should have been added to session history with sender attribution
+	defaultAgent := al.registry.GetDefaultAgent()
+	if defaultAgent == nil {
+		t.Fatal("expected default agent")
+	}
+	history := defaultAgent.Sessions.GetHistory(sessionKey)
+	if len(history) == 0 {
+		t.Fatal("expected observe-only message to be stored in session history")
+	}
+	last := history[len(history)-1]
+	if last.Role != "user" {
+		t.Fatalf("expected role 'user', got %q", last.Role)
+	}
+	if !strings.Contains(last.Content, "Alice") || !strings.Contains(last.Content, "we should meet at 3pm") {
+		t.Fatalf("expected sender attribution and content in history, got %q", last.Content)
+	}
+}
+
+func TestObserveOnlyMessage_DoesNotRespondEvenWithContinuation(t *testing.T) {
+	tmpDir := t.TempDir()
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				Workspace:         tmpDir,
+				ModelName:         "test-model",
+				MaxTokens:         4096,
+				MaxToolIterations: 10,
+			},
+		},
+	}
+
+	msgBus := bus.NewMessageBus()
+	provider := &countingMockProvider{response: "LLM reply"}
+	al := NewAgentLoop(cfg, msgBus, provider)
+
+	// Send multiple observe-only messages
+	for _, content := range []string{"msg1", "msg2", "msg3"} {
+		msg := bus.InboundMessage{
+			Channel:     "slack",
+			SenderID:    "slack:userA",
+			ChatID:      "channel1",
+			Content:     content,
+			Peer:        bus.Peer{Kind: "channel", ID: "channel1"},
+			ObserveOnly: true,
+		}
+		if _, err := al.processMessage(context.Background(), msg); err != nil {
+			t.Fatalf("processMessage(%q) error = %v", content, err)
+		}
+	}
+
+	if provider.calls != 0 {
+		t.Fatalf("expected 0 LLM calls for observe-only messages, got %d", provider.calls)
+	}
+
+	// Confirm history accumulated
+	route := al.registry.ResolveRoute(routing.RouteInput{
+		Channel: "slack",
+		Peer:    bus.Peer{Kind: "channel", ID: "channel1"},
+	})
+	defaultAgent := al.registry.GetDefaultAgent()
+	if defaultAgent == nil {
+		t.Fatal("expected default agent")
+	}
+	history := defaultAgent.Sessions.GetHistory(route.SessionKey)
+	if len(history) != 3 {
+		t.Fatalf("expected 3 observed messages in history, got %d", len(history))
+	}
+}

pkg/bus/types.go

@@ -27,6 +27,7 @@ type InboundMessage struct {
 	MediaScope  string            `json:"media_scope,omitempty"` // media lifecycle scope
 	SessionKey  string            `json:"session_key"`
 	Metadata    map[string]string `json:"metadata,omitempty"`
+	ObserveOnly bool              `json:"observe_only,omitempty"` // store in history but do not respond
 }
 
 type OutboundMessage struct {

pkg/channels/base.go

@@ -329,6 +329,62 @@ func (c *BaseChannel) HandleMessage(
 	}
 }
 
+// ObserveGroupMessage records a group message into conversation history without triggering a response.
+// It is called when ShouldRespondInGroup returns false but the message should still be retained
+// as context (e.g. mention_only mode). Unlike HandleMessage, it does not start typing indicators,
+// reactions, or placeholder messages.
+func (c *BaseChannel) ObserveGroupMessage(
+	ctx context.Context,
+	peer bus.Peer,
+	messageID, senderID, chatID, content string,
+	media []string,
+	metadata map[string]string,
+	senderOpts ...bus.SenderInfo,
+) {
+	var sender bus.SenderInfo
+	if len(senderOpts) > 0 {
+		sender = senderOpts[0]
+	}
+	if sender.CanonicalID != "" || sender.PlatformID != "" {
+		if !c.IsAllowedSender(sender) {
+			return
+		}
+	} else {
+		if !c.IsAllowed(senderID) {
+			return
+		}
+	}
+
+	resolvedSenderID := senderID
+	if sender.CanonicalID != "" {
+		resolvedSenderID = sender.CanonicalID
+	}
+
+	scope := BuildMediaScope(c.name, chatID, messageID)
+
+	msg := bus.InboundMessage{
+		Channel:     c.name,
+		SenderID:    resolvedSenderID,
+		Sender:      sender,
+		ChatID:      chatID,
+		Content:     content,
+		Media:       media,
+		Peer:        peer,
+		MessageID:   messageID,
+		MediaScope:  scope,
+		Metadata:    metadata,
+		ObserveOnly: true,
+	}
+
+	if err := c.bus.PublishInbound(ctx, msg); err != nil {
+		logger.DebugCF("channels", "Failed to publish observed group message", map[string]any{
+			"channel": c.name,
+			"chat_id": chatID,
+			"error":   err.Error(),
+		})
+	}
+}
+
 func (c *BaseChannel) SetRunning(running bool) {
 	c.running.Store(running)
 }

pkg/channels/base_test.go

@@ -1,7 +1,9 @@
 package channels
 
 import (
+	"context"
 	"testing"
+	"time"
 
 	"github.com/sipeed/picoclaw/pkg/bus"
 	"github.com/sipeed/picoclaw/pkg/config"
@@ -263,3 +265,72 @@ func TestIsAllowedSender(t *testing.T) {
 		})
 	}
 }
+
+func TestObserveGroupMessage_PublishesObserveOnly(t *testing.T) {
+	mb := bus.NewMessageBus()
+	defer mb.Close()
+
+	ch := NewBaseChannel("test", nil, mb, nil)
+
+	peer := bus.Peer{Kind: "group", ID: "group123"}
+	sender := bus.SenderInfo{
+		Platform:    "test",
+		PlatformID:  "user1",
+		CanonicalID: "test:user1",
+		DisplayName: "Alice",
+	}
+
+	go ch.ObserveGroupMessage(
+		context.Background(),
+		peer,
+		"msg1", "user1", "group123", "hello world",
+		nil, nil, sender,
+	)
+
+	select {
+	case msg := <-mb.InboundChan():
+		if !msg.ObserveOnly {
+			t.Fatalf("expected ObserveOnly=true, got false")
+		}
+		if msg.Channel != "test" {
+			t.Fatalf("expected channel 'test', got %q", msg.Channel)
+		}
+		if msg.Content != "hello world" {
+			t.Fatalf("expected content 'hello world', got %q", msg.Content)
+		}
+		if msg.Peer.Kind != "group" {
+			t.Fatalf("expected peer kind 'group', got %q", msg.Peer.Kind)
+		}
+	case <-time.After(time.Second):
+		t.Fatal("timed out waiting for observe-only message on bus")
+	}
+}
+
+func TestObserveGroupMessage_SkipsTypingAndPlaceholder(t *testing.T) {
+	// ObserveGroupMessage must not trigger placeholder/typing even if the channel
+	// has those capabilities (the owner is nil so they can't fire, but we verify
+	// the channel field ObserveOnly is set and no extra messages are sent).
+	mb := bus.NewMessageBus()
+	defer mb.Close()
+
+	ch := NewBaseChannel("test", nil, mb, nil)
+
+	peer := bus.Peer{Kind: "group", ID: "g1"}
+	go ch.ObserveGroupMessage(context.Background(), peer, "", "s1", "g1", "hi", nil, nil)
+
+	select {
+	case msg := <-mb.InboundChan():
+		if !msg.ObserveOnly {
+			t.Fatalf("expected ObserveOnly=true")
+		}
+	case <-time.After(time.Second):
+		t.Fatal("timed out")
+	}
+
+	// No second message (no placeholder / typing broadcast)
+	select {
+	case extra := <-mb.InboundChan():
+		t.Fatalf("unexpected extra message: %+v", extra)
+	default:
+	}
+}

pkg/channels/dingtalk/dingtalk.go

@@ -197,6 +197,13 @@ func (c *DingTalkChannel) onChatBotMessageReceived(
 		// In group chats, apply unified group trigger filtering
 		respond, cleaned := c.ShouldRespondInGroup(isMentioned, content)
 		if !respond {
+			observeSender := bus.SenderInfo{
+				Platform:    "dingtalk",
+				PlatformID:  senderID,
+				CanonicalID: identity.BuildCanonicalID("dingtalk", senderID),
+				DisplayName: senderNick,
+			}
+			c.ObserveGroupMessage(ctx, peer, "", senderID, chatID, content, nil, metadata, observeSender)
 			return nil, nil
 		}
 		content = cleaned

pkg/channels/discord/discord.go

@@ -416,6 +416,13 @@ func (c *DiscordChannel) handleMessage(s *discordgo.Session, m *discordgo.Messag
 			logger.DebugCF("discord", "Group message ignored by group trigger", map[string]any{
 				"user_id": m.Author.ID,
 			})
+			observePeer := bus.Peer{Kind: "channel", ID: m.ChannelID}
+			observeMeta := map[string]string{
+				"guild_id": m.GuildID,
+				"user_id":  m.Author.ID,
+				"platform": "discord",
+			}
+			c.ObserveGroupMessage(c.ctx, observePeer, m.ID, m.Author.ID, m.ChannelID, content, nil, observeMeta, sender)
 			return
 		}
 		content = cleaned

pkg/channels/feishu/feishu_64.go

@@ -463,6 +463,7 @@ func (c *FeishuChannel) handleMessageReceive(ctx context.Context, event *larkim.
 		// In group chats, apply unified group trigger filtering
 		respond, cleaned := c.ShouldRespondInGroup(isMentioned, content)
 		if !respond {
+			c.ObserveGroupMessage(ctx, peer, messageID, senderID, chatID, content, mediaRefs, metadata, senderInfo)
 			return nil
 		}
 		content = cleaned

pkg/channels/irc/handler.go

@@ -81,6 +81,13 @@ func (c *IRCChannel) onPrivmsg(conn *ircevent.Connection, e ircmsg.Message) {
 		}
 		respond, cleaned := c.ShouldRespondInGroup(isMentioned, content)
 		if !respond {
+			observeID := fmt.Sprintf("%s-%d", nick, time.Now().UnixNano())
+			observeMeta := map[string]string{
+				"platform": "irc",
+				"server":   c.config.Server,
+				"channel":  target,
+			}
+			c.ObserveGroupMessage(c.ctx, peer, observeID, nick, chatID, content, nil, observeMeta, sender)
 			return
 		}
 		content = cleaned

pkg/channels/line/line.go

@@ -357,6 +357,17 @@ func (c *LINEChannel) processEvent(event lineEvent) {
 			logger.DebugCF("line", "Ignoring group message by group trigger", map[string]any{
 				"chat_id": chatID,
 			})
+			observeSender := bus.SenderInfo{
+				Platform:    "line",
+				PlatformID:  senderID,
+				CanonicalID: identity.BuildCanonicalID("line", senderID),
+			}
+			observePeer := bus.Peer{Kind: "group", ID: chatID}
+			observeMeta := map[string]string{
+				"platform":    "line",
+				"source_type": event.Source.Type,
+			}
+			c.ObserveGroupMessage(c.ctx, observePeer, msg.ID, senderID, chatID, content, mediaPaths, observeMeta, observeSender)
 			return
 		}
 		content = cleaned

pkg/channels/matrix/matrix.go

@@ -723,6 +723,12 @@ func (c *MatrixChannel) handleMessageEvent(ctx context.Context, evt *event.Event
 				"mention_only": c.config.GroupTrigger.MentionOnly,
 				"prefixes":     c.config.GroupTrigger.Prefixes,
 			})
+			observePeer := bus.Peer{Kind: "group", ID: roomID}
+			observeMeta := map[string]string{
+				"room_id":  roomID,
+				"platform": "matrix",
+			}
+			c.ObserveGroupMessage(ctx, observePeer, evt.ID.String(), senderID, roomID, content, mediaPaths, observeMeta, sender)
 			return
 		}
 		content = cleaned

pkg/channels/onebot/onebot.go

@@ -1030,6 +1030,13 @@ func (c *OneBotChannel) handleMessage(raw *oneBotRawEvent) {
 				"is_mentioned": isBotMentioned,
 				"content":      truncate(content, 100),
 			})
+			observeSenderInfo := bus.SenderInfo{
+				Platform:    "onebot",
+				PlatformID:  senderID,
+				CanonicalID: identity.BuildCanonicalID("onebot", senderID),
+				DisplayName: sender.Nickname,
+			}
+			c.ObserveGroupMessage(c.ctx, peer, messageID, senderID, chatID, content, nil, metadata, observeSenderInfo)
 			return
 		}
 		content = strippedContent

pkg/channels/slack/slack.go

@@ -316,6 +316,15 @@ func (c *SlackChannel) handleMessageEvent(ev *slackevents.MessageEvent) {
 	if !strings.HasPrefix(channelID, "D") {
 		respond, cleaned := c.ShouldRespondInGroup(false, content)
 		if !respond {
+			observePeer := bus.Peer{Kind: "channel", ID: channelID}
+			observeMeta := map[string]string{
+				"message_ts": messageTS,
+				"channel_id": channelID,
+				"thread_ts":  threadTS,
+				"platform":   "slack",
+				"team_id":    c.teamID,
+			}
+			c.ObserveGroupMessage(c.ctx, observePeer, messageTS, senderID, chatID, content, nil, observeMeta, sender)
 			return
 		}
 		content = cleaned

pkg/channels/telegram/telegram.go

@@ -690,6 +690,16 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 		content = "[media only]"
 	}
 
+	// For forum topics, embed the thread ID as "chatID/threadID" so replies
+	// route to the correct topic and each topic gets its own session.
+	// Only forum groups (IsForum) are handled; regular group reply threads
+	// must share one session per group.
+	compositeChatID := fmt.Sprintf("%d", chatID)
+	threadID := message.MessageThreadID
+	if message.Chat.IsForum && threadID != 0 {
+		compositeChatID = fmt.Sprintf("%d/%d", chatID, threadID)
+	}
+
 	// In group chats, apply unified group trigger filtering
 	if message.Chat.Type != "private" {
 		isMentioned := c.isBotMentioned(message)
@@ -698,6 +708,14 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 		}
 		respond, cleaned := c.ShouldRespondInGroup(isMentioned, content)
 		if !respond {
+			observePeer := bus.Peer{Kind: "group", ID: compositeChatID}
+			observeMeta := map[string]string{
+				"user_id":    platformID,
+				"username":   user.Username,
+				"first_name": user.FirstName,
+				"is_group":   "true",
+			}
+			c.ObserveGroupMessage(ctx, observePeer, messageIDStr, platformID, compositeChatID, content, mediaPaths, observeMeta, sender)
 			return nil
 		}
 		content = cleaned
@@ -720,16 +738,6 @@ func (c *TelegramChannel) handleMessage(ctx context.Context, message *telego.Mes
 		content = c.prependTelegramQuotedReply(content, message.ReplyToMessage)
 	}
 
-	// For forum topics, embed the thread ID as "chatID/threadID" so replies
-	// route to the correct topic and each topic gets its own session.
-	// Only forum groups (IsForum) are handled; regular group reply threads
-	// must share one session per group.
-	compositeChatID := fmt.Sprintf("%d", chatID)
-	threadID := message.MessageThreadID
-	if message.Chat.IsForum && threadID != 0 {
-		compositeChatID = fmt.Sprintf("%d/%d", chatID, threadID)
-	}
-
 	logger.DebugCF("telegram", "Received message", map[string]any{
 		"sender_id": sender.CanonicalID,
 		"chat_id":   compositeChatID,

pkg/channels/whatsapp/whatsapp.go

@@ -35,6 +35,7 @@ func NewWhatsAppChannel(cfg config.WhatsAppConfig, bus *bus.MessageBus) (*WhatsA
 		bus,
 		cfg.AllowFrom,
 		channels.WithMaxMessageLength(65536),
+		channels.WithGroupTrigger(cfg.GroupTrigger),
 		channels.WithReasoningChannelID(cfg.ReasoningChannelID),
 	)
 
@@ -248,5 +249,29 @@ func (c *WhatsAppChannel) handleIncomingMessage(msg map[string]any) {
 		return
 	}
 
+	// In group chats, apply unified group trigger filtering.
+	// Mention detection: check if the "mentions" field in the message payload
+	// contains the sender's own JID (proxy for being mentioned by others),
+	// or use false when no mention info is available.
+	if peer.Kind == "group" {
+		isMentioned := false
+		if mentionList, ok := msg["mentions"].([]any); ok {
+			for _, m := range mentionList {
+				if jid, ok := m.(string); ok && jid != "" {
+					// Any mention in the payload counts as the bot being addressed
+					_ = jid
+					isMentioned = true
+					break
+				}
+			}
+		}
+		respond, cleaned := c.ShouldRespondInGroup(isMentioned, content)
+		if !respond {
+			c.ObserveGroupMessage(c.ctx, peer, messageID, senderID, chatID, content, mediaPaths, metadata, sender)
+			return
+		}
+		content = cleaned
+	}
+
 	c.HandleMessage(c.ctx, peer, messageID, senderID, chatID, content, mediaPaths, metadata, sender)
 }

pkg/config/config.go

@@ -358,6 +358,7 @@ type WhatsAppConfig struct {
 	UseNative          bool                `json:"use_native"           yaml:"-" env:"PICOCLAW_CHANNELS_WHATSAPP_USE_NATIVE"`
 	SessionStorePath   string              `json:"session_store_path"   yaml:"-" env:"PICOCLAW_CHANNELS_WHATSAPP_SESSION_STORE_PATH"`
 	AllowFrom          FlexibleStringSlice `json:"allow_from"           yaml:"-" env:"PICOCLAW_CHANNELS_WHATSAPP_ALLOW_FROM"`
+	GroupTrigger       GroupTriggerConfig  `json:"group_trigger,omitempty" yaml:"-"`
 	ReasoningChannelID string              `json:"reasoning_channel_id" yaml:"-" env:"PICOCLAW_CHANNELS_WHATSAPP_REASONING_CHANNEL_ID"`
 }
 

pkg/config/defaults.go

@@ -51,10 +51,12 @@ func DefaultConfig() *Config {
 				UseNative:        false,
 				SessionStorePath: "",
 				AllowFrom:        FlexibleStringSlice{},
+				GroupTrigger:     GroupTriggerConfig{MentionOnly: false},
 			},
 			Telegram: TelegramConfig{
 				Enabled:      false,
 				AllowFrom:    FlexibleStringSlice{},
+				GroupTrigger: GroupTriggerConfig{MentionOnly: true},
 				Typing:       TypingConfig{Enabled: true},
 				Placeholder: PlaceholderConfig{
 					Enabled: true,
@@ -67,11 +69,13 @@ func DefaultConfig() *Config {
 				Enabled:      false,
 				AppID:        "",
 				AllowFrom:    FlexibleStringSlice{},
+				GroupTrigger: GroupTriggerConfig{MentionOnly: true},
 			},
 			Discord: DiscordConfig{
 				Enabled:      false,
 				AllowFrom:    FlexibleStringSlice{},
 				MentionOnly:  false,
+				GroupTrigger: GroupTriggerConfig{MentionOnly: true},
 			},
 			MaixCam: MaixCamConfig{
 				Enabled:   false,
@@ -83,6 +87,7 @@ func DefaultConfig() *Config {
 				Enabled:              false,
 				AppID:                "",
 				AllowFrom:            FlexibleStringSlice{},
+				GroupTrigger:         GroupTriggerConfig{MentionOnly: true},
 				MaxMessageLength:     2000,
 				MaxBase64FileSizeMiB: 0,
 			},
@@ -90,10 +95,12 @@ func DefaultConfig() *Config {
 				Enabled:      false,
 				ClientID:     "",
 				AllowFrom:    FlexibleStringSlice{},
+				GroupTrigger: GroupTriggerConfig{MentionOnly: true},
 			},
 			Slack: SlackConfig{
 				Enabled:      false,
 				AllowFrom:    FlexibleStringSlice{},
+				GroupTrigger: GroupTriggerConfig{MentionOnly: true},
 			},
 			Matrix: MatrixConfig{
 				Enabled:      false,
@@ -125,6 +132,7 @@ func DefaultConfig() *Config {
 				WSUrl:             "ws://127.0.0.1:3001",
 				ReconnectInterval: 5,
 				AllowFrom:         FlexibleStringSlice{},
+				GroupTrigger:      GroupTriggerConfig{MentionOnly: true},
 			},
 			WeCom: WeComConfig{
 				Enabled:             false,
@@ -148,6 +156,11 @@ func DefaultConfig() *Config {
 				MaxConnections: 100,
 				AllowFrom:      FlexibleStringSlice{},
 			},
+			IRC: IRCConfig{
+				Enabled:      false,
+				AllowFrom:    FlexibleStringSlice{},
+				GroupTrigger: GroupTriggerConfig{MentionOnly: true},
+			},
 		},
 		Hooks: HooksConfig{
 			Enabled: true,