diff --git a/pkg/tools/mcp_external_integration_test.go b/pkg/tools/mcp_external_integration_test.go
new file mode 100644
index 000000000..077709f3a
--- /dev/null
+++ b/pkg/tools/mcp_external_integration_test.go
@@ -0,0 +1,221 @@
+package tools
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/sipeed/picoclaw/pkg/config"
+)
+
+// These tests exercise real/popular MCP servers and therefore require network/npm.
+// Run explicitly with:
+//   PICOCLAW_RUN_EXTERNAL_MCP_TESTS=1 go test ./pkg/tools -run MCPExternal -v
+
+func TestMCPExternalPopularFilesystemCommand(t *testing.T) {
+	requireExternalMCPTests(t)
+
+	root := t.TempDir()
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
+	defer cancel()
+
+	cfg := config.MCPToolsConfig{
+		Enabled: true,
+		Servers: []config.MCPServerConfig{
+			{
+				Name:             "filesystem",
+				Enabled:          true,
+				Transport:        "command",
+				Command:          "npx",
+				Args:             []string{"-y", "@modelcontextprotocol/server-filesystem", root},
+				ToolPrefix:       "mcp_fs",
+				StartupTimeoutMS: 30000,
+				CallTimeoutMS:    30000,
+			},
+		},
+	}
+
+	tools, err := LoadMCPTools(ctx, cfg, "")
+	if err != nil {
+		t.Fatalf("LoadMCPTools() error: %v", err)
+	}
+
+	tool := findToolByName(tools, "mcp_fs_list_allowed_directories")
+	if tool == nil {
+		t.Fatalf("missing tool mcp_fs_list_allowed_directories; got %v", toolNames(tools))
+	}
+
+	out, err := tool.Execute(ctx, map[string]interface{}{})
+	if err != nil {
+		t.Fatalf("Execute(list_allowed_directories) error: %v", err)
+	}
+	if !strings.Contains(out, root) {
+		t.Fatalf("expected allowed directory %q in output: %s", root, out)
+	}
+}
+
+func TestMCPExternalPopularMemoryCommand(t *testing.T) {
+	requireExternalMCPTests(t)
+
+	memoryFile := filepath.Join(t.TempDir(), "memory.jsonl")
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
+	defer cancel()
+
+	cfg := config.MCPToolsConfig{
+		Enabled: true,
+		Servers: []config.MCPServerConfig{
+			{
+				Name:             "memory",
+				Enabled:          true,
+				Transport:        "command",
+				Command:          "npx",
+				Args:             []string{"-y", "@modelcontextprotocol/server-memory"},
+				Env:              map[string]string{"MEMORY_FILE_PATH": memoryFile},
+				ToolPrefix:       "mcp_memory",
+				StartupTimeoutMS: 30000,
+				CallTimeoutMS:    30000,
+			},
+		},
+	}
+
+	tools, err := LoadMCPTools(ctx, cfg, "")
+	if err != nil {
+		t.Fatalf("LoadMCPTools() error: %v", err)
+	}
+
+	readGraph := findToolByName(tools, "mcp_memory_read_graph")
+	if readGraph == nil {
+		t.Fatalf("missing tool mcp_memory_read_graph; got %v", toolNames(tools))
+	}
+
+	out, err := readGraph.Execute(ctx, map[string]interface{}{})
+	if err != nil {
+		t.Fatalf("Execute(read_graph) error: %v", err)
+	}
+	if !strings.Contains(strings.ToLower(out), "entities") {
+		t.Fatalf("expected graph output to include entities: %s", out)
+	}
+}
+
+func TestMCPExternalPopularEverythingSSE(t *testing.T) {
+	requireExternalMCPTests(t)
+
+	port := pickFreePort(t)
+	cmd := startEverythingSSEServer(t, port)
+	waitForTCPPort(t, fmt.Sprintf("127.0.0.1:%d", port), 15*time.Second)
+
+	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
+	defer cancel()
+
+	cfg := config.MCPToolsConfig{
+		Enabled: true,
+		Servers: []config.MCPServerConfig{
+			{
+				Name:             "everything",
+				Enabled:          true,
+				Transport:        "sse",
+				URL:              fmt.Sprintf("http://127.0.0.1:%d/sse", port),
+				ToolPrefix:       "mcp_every",
+				StartupTimeoutMS: 30000,
+				CallTimeoutMS:    30000,
+			},
+		},
+	}
+
+	tools, err := LoadMCPTools(ctx, cfg, "")
+	if err != nil {
+		t.Fatalf("LoadMCPTools() error: %v", err)
+	}
+
+	echoTool := findToolByName(tools, "mcp_every_echo")
+	if echoTool == nil {
+		t.Fatalf("missing tool mcp_every_echo; got %v", toolNames(tools))
+	}
+
+	out, err := echoTool.Execute(ctx, map[string]interface{}{"message": "hello from sse"})
+	if err != nil {
+		t.Fatalf("Execute(echo) error: %v", err)
+	}
+	if !strings.Contains(out, "Echo: hello from sse") {
+		t.Fatalf("unexpected echo output: %s", out)
+	}
+
+	_ = cmd
+}
+
+func requireExternalMCPTests(t *testing.T) {
+	t.Helper()
+	if os.Getenv("PICOCLAW_RUN_EXTERNAL_MCP_TESTS") != "1" {
+		t.Skip("set PICOCLAW_RUN_EXTERNAL_MCP_TESTS=1 to run external MCP integration tests")
+	}
+	if _, err := exec.LookPath("npx"); err != nil {
+		t.Skip("npx not found")
+	}
+}
+
+func findToolByName(tools []Tool, name string) Tool {
+	for _, tool := range tools {
+		if tool.Name() == name {
+			return tool
+		}
+	}
+	return nil
+}
+
+func pickFreePort(t *testing.T) int {
+	t.Helper()
+	ln, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("pick free port: %v", err)
+	}
+	defer ln.Close()
+
+	addr, ok := ln.Addr().(*net.TCPAddr)
+	if !ok {
+		t.Fatalf("unexpected listener addr type: %T", ln.Addr())
+	}
+	return addr.Port
+}
+
+func waitForTCPPort(t *testing.T, addr string, timeout time.Duration) {
+	t.Helper()
+	deadline := time.Now().Add(timeout)
+	for time.Now().Before(deadline) {
+		conn, err := net.DialTimeout("tcp", addr, 300*time.Millisecond)
+		if err == nil {
+			_ = conn.Close()
+			return
+		}
+		time.Sleep(120 * time.Millisecond)
+	}
+	t.Fatalf("port %s did not become ready within %v", addr, timeout)
+}
+
+func startEverythingSSEServer(t *testing.T, port int) *exec.Cmd {
+	t.Helper()
+
+	cmd := exec.Command("npx", "-y", "@modelcontextprotocol/server-everything", "sse")
+	cmd.Env = append(os.Environ(), fmt.Sprintf("PORT=%d", port))
+	cmd.Stdout = os.Stderr
+	cmd.Stderr = os.Stderr
+
+	if err := cmd.Start(); err != nil {
+		t.Fatalf("start everything sse server: %v", err)
+	}
+
+	t.Cleanup(func() {
+		if cmd.Process == nil {
+			return
+		}
+		_ = cmd.Process.Kill()
+		_, _ = cmd.Process.Wait()
+	})
+
+	return cmd
+}