fix(feishu): preserve mention identity and sender open_id in messages

- Replace @_user_N placeholders with @Name(open_id:xxx) instead of
  stripping them, so downstream tools can still extract user IDs
- Bot mentions are still stripped for trigger detection
- Fix mention handling not applied in p2p (direct) chats
- Inject sender open_id into message content and metadata so the LLM
  knows who sent the message

pkg/channels/feishu/common.go

@@ -69,18 +69,42 @@ func extractFileKey(content string) string { return extractJSONStringField(conte
 // extractFileName extracts the file_name from a Feishu file message content JSON.
 func extractFileName(content string) string { return extractJSONStringField(content, "file_name") }
 
-// stripMentionPlaceholders removes @_user_N placeholders from the text content.
-// These are inserted by Feishu when users @mention someone in a message.
-func stripMentionPlaceholders(content string, mentions []*larkim.MentionEvent) string {
+// stripMentionPlaceholders replaces @_user_N placeholders in the text content.
+// Bot mentions are removed; other user mentions are replaced with @Name(open_id:xxx)
+// so downstream tools can still extract the user ID.
+func stripMentionPlaceholders(content string, mentions []*larkim.MentionEvent, botOpenID string) string {
 	if len(mentions) == 0 {
 		return content
 	}
 	for _, m := range mentions {
-		if m.Key != nil && *m.Key != "" {
-			content = strings.ReplaceAll(content, *m.Key, "")
+		if m.Key == nil || *m.Key == "" {
+			continue
 		}
+		// If this mention is the bot itself, strip it.
+		if botOpenID != "" && m.Id != nil && m.Id.OpenId != nil && *m.Id.OpenId == botOpenID {
+			content = strings.ReplaceAll(content, *m.Key, "")
+			continue
+		}
+		// Replace with @Name(open_id:xxx) to preserve identity for downstream use.
+		replacement := ""
+		name := ""
+		if m.Name != nil {
+			name = *m.Name
+		}
+		openID := ""
+		if m.Id != nil && m.Id.OpenId != nil {
+			openID = *m.Id.OpenId
+		}
+		if name != "" && openID != "" {
+			replacement = "@" + name + "(open_id:" + openID + ")"
+		} else if name != "" {
+			replacement = "@" + name
+		} else if openID != "" {
+			replacement = "@user(open_id:" + openID + ")"
+		}
+		content = strings.ReplaceAll(content, *m.Key, replacement)
 	}
-	// Also clean up any remaining @_user_N patterns
+	// Clean up any remaining @_user_N patterns not covered by mentions list
 	content = mentionPlaceholderRegex.ReplaceAllString(content, "")
 	return strings.TrimSpace(content)
 }

pkg/channels/feishu/common_test.go

@@ -230,6 +230,8 @@ func TestBuildMarkdownCard(t *testing.T) {
 func TestStripMentionPlaceholders(t *testing.T) {
 	strPtr := func(s string) *string { return &s }
 
+	botOpenID := "ou_bot123"
+
 	tests := []struct {
 		name     string
 		content  string
@@ -243,21 +245,37 @@ func TestStripMentionPlaceholders(t *testing.T) {
 			want:     "Hello world",
 		},
 		{
-			name:    "single mention",
+			name:    "bot mention is stripped",
 			content: "@_user_1 hello",
 			mentions: []*larkim.MentionEvent{
-				{Key: strPtr("@_user_1")},
+				{Key: strPtr("@_user_1"), Id: &larkim.UserId{OpenId: strPtr(botOpenID)}, Name: strPtr("Bot")},
 			},
 			want: "hello",
 		},
 		{
-			name:    "multiple mentions",
-			content: "@_user_1 @_user_2 hey",
+			name:    "user mention preserved with name and id",
+			content: "@_user_1 hello",
 			mentions: []*larkim.MentionEvent{
-				{Key: strPtr("@_user_1")},
-				{Key: strPtr("@_user_2")},
+				{Key: strPtr("@_user_1"), Id: &larkim.UserId{OpenId: strPtr("ou_user456")}, Name: strPtr("张三")},
 			},
-			want: "hey",
+			want: "@张三(open_id:ou_user456) hello",
+		},
+		{
+			name:    "mixed bot and user mentions",
+			content: "@_user_1 给我和 @_user_2 拉个群",
+			mentions: []*larkim.MentionEvent{
+				{Key: strPtr("@_user_1"), Id: &larkim.UserId{OpenId: strPtr(botOpenID)}, Name: strPtr("Bot")},
+				{Key: strPtr("@_user_2"), Id: &larkim.UserId{OpenId: strPtr("ou_user789")}, Name: strPtr("李四")},
+			},
+			want: "给我和 @李四(open_id:ou_user789) 拉个群",
+		},
+		{
+			name:    "user mention with name only",
+			content: "@_user_1 hello",
+			mentions: []*larkim.MentionEvent{
+				{Key: strPtr("@_user_1"), Name: strPtr("张三")},
+			},
+			want: "@张三 hello",
 		},
 		{
 			name:     "empty content",
@@ -283,7 +301,7 @@ func TestStripMentionPlaceholders(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got := stripMentionPlaceholders(tt.content, tt.mentions)
+			got := stripMentionPlaceholders(tt.content, tt.mentions, botOpenID)
 			if got != tt.want {
 				t.Errorf("stripMentionPlaceholders(%q, ...) = %q, want %q", tt.content, got, tt.want)
 			}

pkg/channels/feishu/feishu_64.go

@@ -400,6 +400,19 @@ func (c *FeishuChannel) handleMessageReceive(ctx context.Context, event *larkim.
 	if sender != nil && sender.TenantKey != nil {
 		metadata["tenant_key"] = *sender.TenantKey
 	}
+	if senderID != "" {
+		metadata["sender_open_id"] = senderID
+	}
+	// Store the full open_id for API use (senderID may be user_id instead)
+	if sender != nil && sender.SenderId != nil && sender.SenderId.OpenId != nil && *sender.SenderId.OpenId != "" {
+		metadata["sender_open_id"] = *sender.SenderId.OpenId
+	}
+
+	// Replace mention placeholders for all chat types: bot mentions are stripped, others become @Name(open_id:xxx)
+	if len(message.Mentions) > 0 {
+		knownBotID, _ := c.botOpenID.Load().(string)
+		content = stripMentionPlaceholders(content, message.Mentions, knownBotID)
+	}
 
 	var peer bus.Peer
 	if chatType == "p2p" {
@@ -410,11 +423,6 @@ func (c *FeishuChannel) handleMessageReceive(ctx context.Context, event *larkim.
 		// Check if bot was mentioned
 		isMentioned := c.isBotMentioned(message)
 
-		// Strip mention placeholders from content before group trigger check
-		if len(message.Mentions) > 0 {
-			content = stripMentionPlaceholders(content, message.Mentions)
-		}
-
 		// In group chats, apply unified group trigger filtering
 		respond, cleaned := c.ShouldRespondInGroup(isMentioned, content)
 		if !respond {
@@ -423,6 +431,17 @@ func (c *FeishuChannel) handleMessageReceive(ctx context.Context, event *larkim.
 		content = cleaned
 	}
 
+	// Prepend sender identity so the LLM knows who sent the message.
+	if sender != nil && sender.SenderId != nil {
+		openID := ""
+		if sender.SenderId.OpenId != nil {
+			openID = *sender.SenderId.OpenId
+		}
+		if openID != "" {
+			content = fmt.Sprintf("[sender: open_id=%s] %s", openID, content)
+		}
+	}
+
 	logger.InfoCF("feishu", "Feishu message received", map[string]any{
 		"sender_id":  senderID,
 		"chat_id":    chatID,