diff --git a/pkg/mcp/transport_tcp_test.go b/pkg/mcp/transport_tcp_test.go
new file mode 100644
index 00000000..e87da0c2
--- /dev/null
+++ b/pkg/mcp/transport_tcp_test.go
@@ -0,0 +1,183 @@
+package mcp
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"net"
+	"os"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestNewTCPTransport_Defaults(t *testing.T) {
+	// Test default address
+	tr, err := NewTCPTransport("")
+	if err != nil {
+		t.Fatalf("Failed to create transport with default address: %v", err)
+	}
+	defer tr.listener.Close()
+
+	if tr.addr != "127.0.0.1:9100" {
+		t.Errorf("Expected default address 127.0.0.1:9100, got %s", tr.addr)
+	}
+}
+
+func TestNewTCPTransport_Warning(t *testing.T) {
+	// Capture stderr
+	oldStderr := os.Stderr
+	r, w, _ := os.Pipe()
+	os.Stderr = w
+	defer func() { os.Stderr = oldStderr }()
+
+	// Trigger warning
+	tr, err := NewTCPTransport("0.0.0.0:9101")
+	if err != nil {
+		t.Fatalf("Failed to create transport: %v", err)
+	}
+	defer tr.listener.Close()
+
+	// Restore stderr
+	w.Close()
+	var buf bytes.Buffer
+	_, _ = io.Copy(&buf, r)
+
+	output := buf.String()
+	if !strings.Contains(output, "WARNING") {
+		t.Error("Expected warning for binding to 0.0.0.0, but didn't find it in stderr")
+	}
+}
+
+func TestServeTCP_Connection(t *testing.T) {
+	s, err := New()
+	if err != nil {
+		t.Fatalf("Failed to create service: %v", err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// Use a random port for testing to avoid collisions
+	addr := "127.0.0.1:0"
+
+	// Create transport first to get the actual address if we use :0
+	tr, err := NewTCPTransport(addr)
+	if err != nil {
+		t.Fatalf("Failed to create transport: %v", err)
+	}
+	actualAddr := tr.listener.Addr().String()
+	tr.listener.Close() // Close it so ServeTCP can re-open it or use the same address
+
+	// Start server in background
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- s.ServeTCP(ctx, actualAddr)
+	}()
+
+	// Give it a moment to start
+	time.Sleep(100 * time.Millisecond)
+
+	// Connect to the server
+	conn, err := net.Dial("tcp", actualAddr)
+	if err != nil {
+		t.Fatalf("Failed to connect to server: %v", err)
+	}
+	defer conn.Close()
+
+	// Verify we can write to it
+	_, err = conn.Write([]byte("{}\n"))
+	if err != nil {
+		t.Errorf("Failed to write to connection: %v", err)
+	}
+
+	// Shutdown server
+	cancel()
+	err = <-errCh
+	if err != nil {
+		t.Errorf("ServeTCP returned error: %v", err)
+	}
+}
+
+func TestRun_TCPTrigger(t *testing.T) {
+	s, err := New()
+	if err != nil {
+		t.Fatalf("Failed to create service: %v", err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	// Set MCP_ADDR to empty to trigger default TCP
+	os.Setenv("MCP_ADDR", "")
+	defer os.Unsetenv("MCP_ADDR")
+
+	// We use a random port for testing, but Run will try to use 127.0.0.1:9100 by default if we don't override.
+	// Since 9100 might be in use, we'll set MCP_ADDR to use :0 (random port)
+	os.Setenv("MCP_ADDR", "127.0.0.1:0")
+
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- s.Run(ctx)
+	}()
+
+	// Give it a moment to start
+	time.Sleep(100 * time.Millisecond)
+
+	// Since we can't easily get the actual port used by Run (it's internal),
+	// we just verify it didn't immediately fail.
+	select {
+	case err := <-errCh:
+		t.Fatalf("Run failed immediately: %v", err)
+	default:
+		// still running, which is good
+	}
+
+	cancel()
+	_ = <-errCh
+}
+
+func TestServeTCP_MultipleConnections(t *testing.T) {
+	s, err := New()
+	if err != nil {
+		t.Fatalf("Failed to create service: %v", err)
+	}
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	addr := "127.0.0.1:0"
+	tr, err := NewTCPTransport(addr)
+	if err != nil {
+		t.Fatalf("Failed to create transport: %v", err)
+	}
+	actualAddr := tr.listener.Addr().String()
+	tr.listener.Close()
+
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- s.ServeTCP(ctx, actualAddr)
+	}()
+
+	time.Sleep(100 * time.Millisecond)
+
+	// Connect multiple clients
+	const numClients = 3
+	for i := 0; i < numClients; i++ {
+		conn, err := net.Dial("tcp", actualAddr)
+		if err != nil {
+			t.Fatalf("Client %d failed to connect: %v", i, err)
+		}
+		defer conn.Close()
+		_, err = conn.Write([]byte("{}\n"))
+		if err != nil {
+			t.Errorf("Client %d failed to write: %v", i, err)
+		}
+	}
+
+	cancel()
+	err = <-errCh
+	if err != nil {
+		t.Errorf("ServeTCP returned error: %v", err)
+	}
+}