Fix: pass httpHeaders to streamable HTTP transport

internal/mcp/client.go

@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/mark3labs/mcp-go/client"
+	mcptransport "github.com/mark3labs/mcp-go/client/transport"
 	"github.com/mark3labs/mcp-go/mcp"
 
 	customErrors "github.com/tuannvm/slack-mcp-client/internal/common/errors"
@@ -93,7 +94,12 @@ func NewClient(transport, addressOrCommand string, serverName string, args []str
 			return nil, customErrors.WrapMCPError(err, "client_start", fmt.Sprintf("Failed to start MCP client for %s", addressOrCommand))
 		}
 	case "http":
-		mcpClient, err = client.NewStreamableHttpClient(addressOrCommand)
+		// Convert resolvedHeaders map to map[string]string for streamable HTTP transport
+		httpHeaders := make(map[string]string)
+		for k, v := range resolvedHeaders {
+			httpHeaders[k] = v
+		}
+		mcpClient, err = client.NewStreamableHttpClient(addressOrCommand, mcptransport.WithHTTPHeaders(httpHeaders))
 		if err != nil {
 			return nil, customErrors.WrapMCPError(err, "client_creation", fmt.Sprintf("Failed to create MCP client for %s", addressOrCommand))
 		}

internal/slack/agentCallbackHandler.go

@@ -2,6 +2,8 @@ package slackbot
 
 import (
 	"context"
+	"strings"
+
 	"github.com/tmc/langchaingo/callbacks"
 )
 
@@ -13,9 +15,32 @@ type agentCallbackHandler struct {
 }
 
 func (handler *agentCallbackHandler) HandleChainEnd(_ context.Context, outputs map[string]any) {
-	if text, ok := outputs["text"]; ok {
-		if textStr, ok := text.(string); ok {
-			handler.sendMessage(textStr)
-		}
+	text, ok := outputs["text"]
+	if !ok {
+		return
+	}
+	textStr, ok := text.(string)
+	if !ok {
+		return
+	}
+
+	// Only send the final answer to the user.
+	// Intermediate agent steps contain "Action:" and "Action Input:" lines
+	// which are internal reasoning and should not be shown.
+	// The final answer uses the format:
+	//   Thought: Do I need to use a tool? No
+	//   AI: <actual response>
+	if strings.Contains(textStr, "Action:") && strings.Contains(textStr, "Action Input:") {
+		// This is an intermediate tool-calling step — suppress it
+		return
+	}
+
+	// Strip the ReAct scaffolding prefix from the final answer
+	if idx := strings.Index(textStr, "AI:"); idx != -1 {
+		textStr = strings.TrimSpace(textStr[idx+3:])
+	}
+
+	if textStr != "" {
+		handler.sendMessage(textStr)
 	}
 }

internal/slack/client.go

@@ -37,6 +37,7 @@ type Client struct {
 	historyLimit    int
 	discoveredTools map[string]mcp.ToolInfo
 	tracingHandler  observability.TracingHandler
+	activeThreads   map[string]bool // channel:threadTS keys where bot has been mentioned
 }
 
 // Message represents a message in the conversation history
@@ -201,6 +202,7 @@ func NewClient(userFrontend UserFrontend, stdLogger *logging.Logger, mcpClients
 		historyLimit:    cfg.Slack.MessageHistory, // Store configured number of messages per channel
 		discoveredTools: discoveredTools,
 		tracingHandler:  tracingHandler,
+		activeThreads:   make(map[string]bool),
 	}, nil
 }
 
@@ -264,6 +266,12 @@ func (c *Client) handleEventMessage(event slackevents.EventsAPIEvent) {
 			if parentTS == "" {
 				parentTS = ev.TimeStamp // Use the original message timestamp if no thread
 			}
+
+			// Track this thread so the bot stays engaged for follow-up messages
+			threadKey := fmt.Sprintf("%s:%s", ev.Channel, parentTS)
+			c.activeThreads[threadKey] = true
+			c.logger.InfoKV("Tracking active thread", "channel", ev.Channel, "threadTS", parentTS)
+
 			// Use handleUserPrompt for app mentions too, for consistency
 			go c.handleUserPrompt(strings.TrimSpace(messageText), ev.Channel, parentTS, ev.TimeStamp, profile)
 
@@ -273,8 +281,19 @@ func (c *Client) handleEventMessage(event slackevents.EventsAPIEvent) {
 			isNotEdited := ev.SubType != "message_changed"
 			isBot := ev.BotID != "" || ev.SubType == "bot_message"
 
-			if isDirectMessage && isValidUser && isNotEdited && !isBot {
-				c.logger.InfoKV("Received direct message in channel", "channel", ev.Channel, "user", ev.User, "text", ev.Text, "ThreadTS", ev.ThreadTimeStamp)
+			// Check if this is a reply in a thread the bot is already participating in
+			isActiveThread := false
+			if ev.ThreadTimeStamp != "" {
+				threadKey := fmt.Sprintf("%s:%s", ev.Channel, ev.ThreadTimeStamp)
+				isActiveThread = c.activeThreads[threadKey]
+			}
+
+			if (isDirectMessage || isActiveThread) && isValidUser && isNotEdited && !isBot {
+				if isActiveThread {
+					c.logger.InfoKV("Received thread follow-up (no @mention needed)", "channel", ev.Channel, "user", ev.User, "text", ev.Text, "ThreadTS", ev.ThreadTimeStamp)
+				} else {
+					c.logger.InfoKV("Received direct message in channel", "channel", ev.Channel, "user", ev.User, "text", ev.Text, "ThreadTS", ev.ThreadTimeStamp)
+				}
 				profile, err := c.userFrontend.GetUserInfo(ev.User)
 				if err != nil {
 					c.logger.WarnKV("Failed to get user info", "user", ev.User, "error", err)