feat: add reactions_list tool to list items user has reacted to

pkg/handler/conversations.go

@@ -95,6 +95,24 @@ type filesGetParams struct {
 	fileID string
 }
 
+type reactionsListParams struct {
+	count int
+	page  int
+	full  bool
+}
+
+type ReactedItemRow struct {
+	Type      string `csv:"type"`
+	Channel   string `csv:"channel"`
+	Timestamp string `csv:"timestamp"`
+	Emoji     string `csv:"emoji"`
+	Text      string `csv:"text"`
+	UserID    string `csv:"userID"`
+	UserName  string `csv:"userName"`
+	Time      string `csv:"time"`
+	Cursor    string `csv:"cursor"`
+}
+
 type ConversationsHandler struct {
 	apiProvider *provider.ApiProvider
 	logger      *zap.Logger
@@ -324,6 +342,120 @@ func (ch *ConversationsHandler) ReactionsRemoveHandler(ctx context.Context, requ
 	return mcp.NewToolResultText(fmt.Sprintf("Successfully removed :%s: reaction from message %s in channel %s", params.emoji, params.timestamp, params.channel)), nil
 }
 
+// ReactionsListHandler lists items the authenticated user has reacted to
+func (ch *ConversationsHandler) ReactionsListHandler(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+	ch.logger.Debug("ReactionsListHandler called", zap.Any("params", request.Params))
+
+	// provider readiness
+	if ready, err := ch.apiProvider.IsReady(); !ready {
+		ch.logger.Error("API provider not ready", zap.Error(err))
+		return nil, err
+	}
+
+	params, err := ch.parseParamsToolReactionsList(request)
+	if err != nil {
+		ch.logger.Error("Failed to parse reactions_list params", zap.Error(err))
+		return nil, err
+	}
+
+	listParams := slack.ListReactionsParameters{
+		Count: params.count,
+		Page:  params.page,
+		Full:  params.full,
+	}
+
+	ch.logger.Debug("Listing reactions",
+		zap.Int("count", params.count),
+		zap.Int("page", params.page),
+		zap.Bool("full", params.full),
+	)
+
+	reactedItems, paging, err := ch.apiProvider.Slack().ListReactionsContext(ctx, listParams)
+	if err != nil {
+		ch.logger.Error("Slack ListReactionsContext failed", zap.Error(err))
+		return nil, err
+	}
+	ch.logger.Debug("Fetched reacted items", zap.Int("count", len(reactedItems)))
+
+	rows := ch.convertReactedItems(reactedItems)
+
+	// Add pagination cursor to the last row if there are more pages
+	if len(rows) > 0 && paging != nil && paging.Page < paging.Pages {
+		rows[len(rows)-1].Cursor = fmt.Sprintf("%d", paging.Page+1)
+	}
+
+	return marshalReactedItemsToCSV(rows)
+}
+
+func (ch *ConversationsHandler) convertReactedItems(items []slack.ReactedItem) []ReactedItemRow {
+	usersMap := ch.apiProvider.ProvideUsersMap()
+	var rows []ReactedItemRow
+
+	for _, item := range items {
+		// Get message text and user info
+		var msgText, userID, userName, timestamp, channel string
+		channel = item.Channel
+
+		switch item.Type {
+		case "message":
+			if item.Message != nil {
+				msgText = item.Message.Text
+				userID = item.Message.User
+				timestamp = item.Message.Timestamp
+			}
+		case "file":
+			if item.File != nil {
+				msgText = item.File.Name
+				userID = item.File.User
+				timestamp = item.File.Timestamp.String()
+			}
+		case "file_comment":
+			if item.Comment != nil {
+				msgText = item.Comment.Comment
+				userID = item.Comment.User
+				timestamp = fmt.Sprintf("%d", item.Comment.Timestamp)
+			}
+		}
+
+		// Resolve username
+		if u, ok := usersMap.Users[userID]; ok {
+			userName = u.Name
+		} else {
+			userName = userID
+		}
+
+		// Convert timestamp to readable format
+		timeStr, err := text.TimestampToIsoRFC3339(timestamp)
+		if err != nil {
+			timeStr = timestamp
+		}
+
+		// Create a row for each reaction on this item
+		for _, reaction := range item.Reactions {
+			rows = append(rows, ReactedItemRow{
+				Type:      item.Type,
+				Channel:   channel,
+				Timestamp: timestamp,
+				Emoji:     reaction.Name,
+				Text:      text.ProcessText(msgText),
+				UserID:    userID,
+				UserName:  userName,
+				Time:      timeStr,
+			})
+		}
+	}
+
+	return rows
+}
+
+func marshalReactedItemsToCSV(rows []ReactedItemRow) (*mcp.CallToolResult, error) {
+	csvBytes, err := gocsv.MarshalBytes(&rows)
+	if err != nil {
+		return nil, err
+	}
+	return mcp.NewToolResultText(string(csvBytes)), nil
+}
+
 func (ch *ConversationsHandler) FilesGetHandler(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
 	ch.logger.Debug("FilesGetHandler called", zap.Any("params", request.Params))
 
@@ -842,6 +974,29 @@ func (ch *ConversationsHandler) parseParamsToolReaction(request mcp.CallToolRequ
 	}, nil
 }
 
+func (ch *ConversationsHandler) parseParamsToolReactionsList(request mcp.CallToolRequest) (*reactionsListParams, error) {
+	count := request.GetInt("count", 100)
+	if count < 1 {
+		count = 100
+	}
+	if count > 1000 {
+		count = 1000
+	}
+
+	page := request.GetInt("page", 1)
+	if page < 1 {
+		page = 1
+	}
+
+	full := request.GetBool("full", true)
+
+	return &reactionsListParams{
+		count: count,
+		page:  page,
+		full:  full,
+	}, nil
+}
+
 func (ch *ConversationsHandler) parseParamsToolFilesGet(request mcp.CallToolRequest) (*filesGetParams, error) {
 	toolConfig := os.Getenv("SLACK_MCP_ATTACHMENT_TOOL")
 	if toolConfig == "" {

pkg/provider/api.go

@@ -79,6 +79,7 @@ type SlackAPI interface {
 	MarkConversationContext(ctx context.Context, channel, ts string) error
 	AddReactionContext(ctx context.Context, name string, item slack.ItemRef) error
 	RemoveReactionContext(ctx context.Context, name string, item slack.ItemRef) error
+	ListReactionsContext(ctx context.Context, params slack.ListReactionsParameters) ([]slack.ReactedItem, *slack.Paging, error)
 
 	// Used to get messages
 	GetConversationHistoryContext(ctx context.Context, params *slack.GetConversationHistoryParameters) (*slack.GetConversationHistoryResponse, error)
@@ -301,6 +302,10 @@ func (c *MCPSlackClient) RemoveReactionContext(ctx context.Context, name string,
 	return c.slackClient.RemoveReactionContext(ctx, name, item)
 }
 
+func (c *MCPSlackClient) ListReactionsContext(ctx context.Context, params slack.ListReactionsParameters) ([]slack.ReactedItem, *slack.Paging, error) {
+	return c.slackClient.ListReactionsContext(ctx, params)
+}
+
 func (c *MCPSlackClient) GetFileInfoContext(ctx context.Context, fileID string, count, page int) (*slack.File, []slack.Comment, *slack.Paging, error) {
 	return c.slackClient.GetFileInfoContext(ctx, fileID, count, page)
 }

pkg/server/server.go

@@ -133,6 +133,24 @@ func NewMCPServer(provider *provider.ApiProvider, logger *zap.Logger) *MCPServer
 		),
 	), conversationsHandler.ReactionsRemoveHandler)
 
+	s.AddTool(mcp.NewTool("reactions_list",
+		mcp.WithDescription("List items (messages, files) the authenticated user has reacted to. Useful as a workaround for accessing saved/bookmarked items."),
+		mcp.WithTitleAnnotation("List My Reactions"),
+		mcp.WithReadOnlyHintAnnotation(true),
+		mcp.WithNumber("count",
+			mcp.DefaultNumber(100),
+			mcp.Description("Number of items to return per page (default 100, max 1000)."),
+		),
+		mcp.WithNumber("page",
+			mcp.DefaultNumber(1),
+			mcp.Description("Page number for pagination (default 1)."),
+		),
+		mcp.WithBoolean("full",
+			mcp.DefaultBool(true),
+			mcp.Description("If true, return full message/file details. Default is true."),
+		),
+	), conversationsHandler.ReactionsListHandler)
+
 	s.AddTool(mcp.NewTool("attachment_get_data",
 		mcp.WithDescription("Download an attachment's content by file ID. Returns file metadata and content (text files as-is, binary files as base64). Maximum file size is 5MB."),
 		mcp.WithTitleAnnotation("Get Attachment Data"),