Slack MCP

package server import ( "context" "fmt" "net/http" "time" "github.com/korotovsky/slack-mcp-server/pkg/handler" "github.com/korotovsky/slack-mcp-server/pkg/provider" "github.com/korotovsky/slack-mcp-server/pkg/server/auth" "github.com/korotovsky/slack-mcp-server/pkg/text" "github.com/korotovsky/slack-mcp-server/pkg/version" "github.com/mark3labs/mcp-go/mcp" "github.com/mark3labs/mcp-go/server" "go.uber.org/zap" ) type MCPServer struct { server *server.MCPServer logger *zap.Logger } func NewMCPServer(provider *provider.ApiProvider, logger *zap.Logger) *MCPServer { s := server.NewMCPServer( "Slack MCP Server", version.Version, server.WithLogging(), server.WithRecovery(), server.WithToolHandlerMiddleware(buildLoggerMiddleware(logger)), server.WithToolHandlerMiddleware(auth.BuildMiddleware(provider.ServerTransport(), logger)), ) conversationsHandler := handler.NewConversationsHandler(provider, logger) s.AddTool(mcp.NewTool("conversations_history", mcp.WithDescription("Get messages from the channel (or DM) by channel_id, the last row/column in the response is used as 'cursor' parameter for pagination if not empty"), mcp.WithString("channel_id", mcp.Required(), mcp.Description(" - `channel_id` (string): ID of the channel in format Cxxxxxxxxxx or its name starting with #... or @... aka #general or @username_dm."), ), mcp.WithBoolean("include_activity_messages", mcp.Description("If true, the response will include activity messages such as 'channel_join' or 'channel_leave'. Default is boolean false."), mcp.DefaultBool(false), ), mcp.WithString("cursor", mcp.Description("Cursor for pagination. Use the value of the last row and column in the response as next_cursor field returned from the previous request."), ), mcp.WithString("limit", mcp.DefaultString("1d"), mcp.Description("Limit of messages to fetch in format of maximum ranges of time (e.g. 1d - 1 day, 1w - 1 week, 30d - 30 days, 90d - 90 days which is a default limit for free tier history) or number of messages (e.g. 50). Must be empty when 'cursor' is provided."), ), ), conversationsHandler.ConversationsHistoryHandler) s.AddTool(mcp.NewTool("conversations_replies", mcp.WithDescription("Get a thread of messages posted to a conversation by channelID and thread_ts, the last row/column in the response is used as 'cursor' parameter for pagination if not empty"), mcp.WithString("channel_id", mcp.Required(), mcp.Description("ID of the channel in format Cxxxxxxxxxx or its name starting with #... or @... aka #general or @username_dm."), ), mcp.WithString("thread_ts", mcp.Required(), mcp.Description("Unique identifier of either a thread's parent message or a message in the thread. ts must be the timestamp in format 1234567890.123456 of an existing message with 0 or more replies."), ), mcp.WithBoolean("include_activity_messages", mcp.Description("If true, the response will include activity messages such as 'channel_join' or 'channel_leave'. Default is boolean false."), mcp.DefaultBool(false), ), mcp.WithString("cursor", mcp.Description("Cursor for pagination. Use the value of the last row and column in the response as next_cursor field returned from the previous request."), ), mcp.WithString("limit", mcp.DefaultString("1d"), mcp.Description("Limit of messages to fetch in format of maximum ranges of time (e.g. 1d - 1 day, 30d - 30 days, 90d - 90 days which is a default limit for free tier history) or number of messages (e.g. 50). Must be empty when 'cursor' is provided."), ), ), conversationsHandler.ConversationsRepliesHandler) s.AddTool(mcp.NewTool("conversations_add_message", mcp.WithDescription("Add a message to a public channel, private channel, or direct message (DM, or IM) conversation by channel_id and thread_ts."), mcp.WithString("channel_id", mcp.Required(), mcp.Description("ID of the channel in format Cxxxxxxxxxx or its name starting with #... or @... aka #general or @username_dm."), ), mcp.WithString("thread_ts", mcp.Description("Unique identifier of either a thread's parent message or a message in the thread_ts must be the timestamp in format 1234567890.123456 of an existing message with 0 or more replies. Optional, if not provided the message will be added to the channel itself, otherwise it will be added to the thread."), ), mcp.WithString("payload", mcp.Description("Message payload in specified content_type format. Example: 'Hello, world!' for text/plain or '# Hello, world!' for text/markdown."), ), mcp.WithString("content_type", mcp.DefaultString("text/markdown"), mcp.Description("Content type of the message. Default is 'text/markdown'. Allowed values: 'text/markdown', 'text/plain'."), ), ), conversationsHandler.ConversationsAddMessageHandler) s.AddTool(mcp.NewTool("conversations_search_messages", mcp.WithDescription("Search messages in a public channel, private channel, or direct message (DM, or IM) conversation using filters. All filters are optional, if not provided then search_query is required."), mcp.WithString("search_query", mcp.Description("Search query to filter messages. Example: 'marketing report' or full URL of Slack message e.g. 'https://slack.com/archives/C1234567890/p1234567890123456', then the tool will return a single message matching given URL, herewith all other parameters will be ignored."), ), mcp.WithString("filter_in_channel", mcp.Description("Filter messages in a specific channel by its ID or name. Example: 'C1234567890' or '#general'. If not provided, all channels will be searched."), ), mcp.WithString("filter_in_im_or_mpim", mcp.Description("Filter messages in a direct message (DM) or multi-person direct message (MPIM) conversation by its ID or name. Example: 'D1234567890' or '@username_dm'. If not provided, all DMs and MPIMs will be searched."), ), mcp.WithString("filter_users_with", mcp.Description("Filter messages with a specific user by their ID or display name in threads and DMs. Example: 'U1234567890' or '@username'. If not provided, all threads and DMs will be searched."), ), mcp.WithString("filter_users_from", mcp.Description("Filter messages from a specific user by their ID or display name. Example: 'U1234567890' or '@username'. If not provided, all users will be searched."), ), mcp.WithString("filter_date_before", mcp.Description("Filter messages sent before a specific date in format 'YYYY-MM-DD'. Example: '2023-10-01', 'July', 'Yesterday' or 'Today'. If not provided, all dates will be searched."), ), mcp.WithString("filter_date_after", mcp.Description("Filter messages sent after a specific date in format 'YYYY-MM-DD'. Example: '2023-10-01', 'July', 'Yesterday' or 'Today'. If not provided, all dates will be searched."), ), mcp.WithString("filter_date_on", mcp.Description("Filter messages sent on a specific date in format 'YYYY-MM-DD'. Example: '2023-10-01', 'July', 'Yesterday' or 'Today'. If not provided, all dates will be searched."), ), mcp.WithString("filter_date_during", mcp.Description("Filter messages sent during a specific period in format 'YYYY-MM-DD'. Example: 'July', 'Yesterday' or 'Today'. If not provided, all dates will be searched."), ), mcp.WithBoolean("filter_threads_only", mcp.Description("If true, the response will include only messages from threads. Default is boolean false."), ), mcp.WithString("cursor", mcp.DefaultString(""), mcp.Description("Cursor for pagination. Use the value of the last row and column in the response as next_cursor field returned from the previous request."), ), mcp.WithNumber("limit", mcp.DefaultNumber(20), mcp.Description("The maximum number of items to return. Must be an integer between 1 and 100."), ), ), conversationsHandler.ConversationsSearchHandler) channelsHandler := handler.NewChannelsHandler(provider, logger) s.AddTool(mcp.NewTool("channels_list", mcp.WithDescription("Get list of channels"), mcp.WithString("channel_types", mcp.Required(), mcp.Description("Comma-separated channel types. Allowed values: 'mpim', 'im', 'public_channel', 'private_channel'. Example: 'public_channel,private_channel,im'"), ), mcp.WithString("sort", mcp.Description("Type of sorting. Allowed values: 'popularity' - sort by number of members/participants in each channel."), ), mcp.WithNumber("limit", mcp.DefaultNumber(100), mcp.Description("The maximum number of items to return. Must be an integer between 1 and 1000 (maximum 999)."), // context fix for cursor: https://github.com/korotovsky/slack-mcp-server/issues/7 ), mcp.WithString("cursor", mcp.Description("Cursor for pagination. Use the value of the last row and column in the response as next_cursor field returned from the previous request."), ), ), channelsHandler.ChannelsHandler) logger.Info("Authenticating with Slack API...", zap.String("context", "console"), ) ar, err := provider.Slack().AuthTest() if err != nil { logger.Fatal("Failed to authenticate with Slack", zap.String("context", "console"), zap.Error(err), ) } logger.Info("Successfully authenticated with Slack", zap.String("context", "console"), zap.String("team", ar.Team), zap.String("user", ar.User), zap.String("enterprise", ar.EnterpriseID), zap.String("url", ar.URL), ) ws, err := text.Workspace(ar.URL) if err != nil { logger.Fatal("Failed to parse workspace from URL", zap.String("context", "console"), zap.String("url", ar.URL), zap.Error(err), ) } s.AddResource(mcp.NewResource( "slack://"+ws+"/channels", "Directory of Slack channels", mcp.WithResourceDescription("This resource provides a directory of Slack channels."), mcp.WithMIMEType("text/csv"), ), channelsHandler.ChannelsResource) s.AddResource(mcp.NewResource( "slack://"+ws+"/users", "Directory of Slack users", mcp.WithResourceDescription("This resource provides a directory of Slack users."), mcp.WithMIMEType("text/csv"), ), conversationsHandler.UsersResource) return &MCPServer{ server: s, logger: logger, } } func (s *MCPServer) ServeSSE(addr string) *server.SSEServer { s.logger.Info("Creating SSE server", zap.String("context", "console"), zap.String("version", version.Version), zap.String("build_time", version.BuildTime), zap.String("commit_hash", version.CommitHash), zap.String("address", addr), ) return server.NewSSEServer(s.server, server.WithBaseURL(fmt.Sprintf("http://%s", addr)), server.WithSSEContextFunc(func(ctx context.Context, r *http.Request) context.Context { ctx = auth.AuthFromRequest(s.logger)(ctx, r) return ctx }), ) } func (s *MCPServer) ServeHTTP(addr string) *server.StreamableHTTPServer { s.logger.Info("Creating HTTP server", zap.String("context", "console"), zap.String("version", version.Version), zap.String("build_time", version.BuildTime), zap.String("commit_hash", version.CommitHash), zap.String("address", addr), ) return server.NewStreamableHTTPServer(s.server, server.WithEndpointPath("/mcp"), server.WithHTTPContextFunc(func(ctx context.Context, r *http.Request) context.Context { ctx = auth.AuthFromRequest(s.logger)(ctx, r) return ctx }), ) } func (s *MCPServer) ServeStdio() error { s.logger.Info("Starting STDIO server", zap.String("version", version.Version), zap.String("build_time", version.BuildTime), zap.String("commit_hash", version.CommitHash), ) err := server.ServeStdio(s.server) if err != nil { s.logger.Error("STDIO server error", zap.Error(err)) } return err } func buildLoggerMiddleware(logger *zap.Logger) server.ToolHandlerMiddleware { return func(next server.ToolHandlerFunc) server.ToolHandlerFunc { return func(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) { logger.Info("Request received", zap.String("tool", req.Params.Name), zap.Any("params", req.Params), ) startTime := time.Now() res, err := next(ctx, req) duration := time.Since(startTime) logger.Info("Request finished", zap.String("tool", req.Params.Name), zap.Duration("duration", duration), ) return res, err } } }