fix(mcp): return aggregated error when all servers fail to connect

- Add errors.Join to return aggregated error when all enabled MCP servers fail
- Track enabled server count separately from total configured servers
- Return error only when all servers fail, not for partial failures
- Improve logging with accurate server counts (enabled vs connected)
- Maintains fault tolerance: partial failures don't stop initialization

pkg/mcp/manager.go

@@ -3,6 +3,7 @@ package mcp
 import (
 	"bufio"
 	"context"
+	"errors"
 	"fmt"
 	"net/http"
 	"os"
@@ -129,6 +130,7 @@ func (m *Manager) LoadFromConfig(ctx context.Context, cfg *config.Config) error
 
 	var wg sync.WaitGroup
 	errs := make(chan error, len(cfg.Tools.MCP.Servers))
+	enabledCount := 0
 
 	for name, serverCfg := range cfg.Tools.MCP.Servers {
 		if !serverCfg.Enabled {
@@ -139,6 +141,7 @@ func (m *Manager) LoadFromConfig(ctx context.Context, cfg *config.Config) error
 			continue
 		}
 
+		enabledCount++
 		wg.Add(1)
 		go func(name string, serverCfg config.MCPServerConfig) {
 			defer wg.Done()
@@ -163,20 +166,32 @@ func (m *Manager) LoadFromConfig(ctx context.Context, cfg *config.Config) error
 		allErrors = append(allErrors, err)
 	}
 
+	connectedCount := len(m.GetServers())
+
+	// If all enabled servers failed to connect, return aggregated error
+	if enabledCount > 0 && connectedCount == 0 {
+		logger.ErrorCF("mcp", "All MCP servers failed to connect",
+			map[string]interface{}{
+				"failed": len(allErrors),
+				"total":  enabledCount,
+			})
+		return errors.Join(allErrors...)
+	}
+
 	if len(allErrors) > 0 {
 		logger.WarnCF("mcp", "Some MCP servers failed to connect",
 			map[string]interface{}{
 				"failed":    len(allErrors),
-				"total":  len(cfg.Tools.MCP.Servers),
+				"connected": connectedCount,
+				"total":     enabledCount,
 			})
-		// Don't fail completely if some servers fail to connect
+		// Don't fail completely if some servers successfully connected
 	}
 
-	connectedCount := len(m.GetServers())
 	logger.InfoCF("mcp", "MCP server initialization complete",
 		map[string]interface{}{
 			"connected": connectedCount,
-			"total":     len(cfg.Tools.MCP.Servers),
+			"total":     enabledCount,
 		})
 
 	return nil