diff --git a/go.sum b/go.sum
index 8d5eb67..a533655 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,3 @@
-dappco.re/go/core v0.4.7 h1:KmIA/2lo6rl1NMtLrKqCWfMlUqpDZYH3q0/d10dTtGA=
-dappco.re/go/core v0.4.7/go.mod h1:f2/tBZ3+3IqDrg2F5F598llv0nmb/4gJVCFzM5geE4A=
 dappco.re/go/core v0.8.0-alpha.1 h1:gj7+Scv+L63Z7wMxbJYHhaRFkHJo2u4MMPuUSv/Dhtk=
 dappco.re/go/core v0.8.0-alpha.1/go.mod h1:f2/tBZ3+3IqDrg2F5F598llv0nmb/4gJVCFzM5geE4A=
 forge.lthn.ai/core/api v0.1.5 h1:NwZrcOyBjaiz5/cn0n0tnlMUodi8Or6FHMx59C7Kv2o=
diff --git a/pkg/mcp/ide/bridge_test.go b/pkg/mcp/ide/bridge_test.go
index f1e3881..ad51959 100644
--- a/pkg/mcp/ide/bridge_test.go
+++ b/pkg/mcp/ide/bridge_test.go
@@ -412,11 +412,10 @@ func TestBridge_Good_NoAuthHeaderWhenTokenEmpty(t *testing.T) {
 	}
 }
 
-func TestBridge_Good_WithTokenOption(t *testing.T) {
-	// Verify the WithToken option function works.
+func TestBridge_Good_ConfigToken(t *testing.T) {
+	// Verify the Config DTO carries token settings through unchanged.
 	cfg := DefaultConfig()
-	opt := WithToken("my-token")
-	opt(&cfg)
+	cfg.Token = "my-token"
 
 	if cfg.Token != "my-token" {
 		t.Errorf("expected token 'my-token', got %q", cfg.Token)
@@ -424,14 +423,14 @@ func TestBridge_Good_WithTokenOption(t *testing.T) {
 }
 
 func TestSubsystem_Good_Name(t *testing.T) {
-	sub := New(nil)
+	sub := New(nil, Config{})
 	if sub.Name() != "ide" {
 		t.Errorf("expected name 'ide', got %q", sub.Name())
 	}
 }
 
 func TestSubsystem_Good_NilHub(t *testing.T) {
-	sub := New(nil)
+	sub := New(nil, Config{})
 	if sub.Bridge() != nil {
 		t.Error("expected nil bridge when hub is nil")
 	}
diff --git a/pkg/mcp/ide/config.go b/pkg/mcp/ide/config.go
index ff64419..8511687 100644
--- a/pkg/mcp/ide/config.go
+++ b/pkg/mcp/ide/config.go
@@ -25,33 +25,22 @@ type Config struct {
 
 // DefaultConfig returns sensible defaults for local development.
 func DefaultConfig() Config {
-	return Config{
-		LaravelWSURL:         "ws://localhost:9876/ws",
-		WorkspaceRoot:        ".",
-		ReconnectInterval:    2 * time.Second,
-		MaxReconnectInterval: 30 * time.Second,
+	return Config{}.WithDefaults()
+}
+
+// WithDefaults fills unset fields with the default development values.
+func (c Config) WithDefaults() Config {
+	if c.LaravelWSURL == "" {
+		c.LaravelWSURL = "ws://localhost:9876/ws"
 	}
-}
-
-// Option configures the IDE subsystem.
-type Option func(*Config)
-
-// WithLaravelURL sets the Laravel WebSocket endpoint.
-func WithLaravelURL(url string) Option {
-	return func(c *Config) { c.LaravelWSURL = url }
-}
-
-// WithWorkspaceRoot sets the workspace root directory.
-func WithWorkspaceRoot(root string) Option {
-	return func(c *Config) { c.WorkspaceRoot = root }
-}
-
-// WithReconnectInterval sets the base reconnect interval.
-func WithReconnectInterval(d time.Duration) Option {
-	return func(c *Config) { c.ReconnectInterval = d }
-}
-
-// WithToken sets the Bearer token for WebSocket authentication.
-func WithToken(token string) Option {
-	return func(c *Config) { c.Token = token }
+	if c.WorkspaceRoot == "" {
+		c.WorkspaceRoot = "."
+	}
+	if c.ReconnectInterval == 0 {
+		c.ReconnectInterval = 2 * time.Second
+	}
+	if c.MaxReconnectInterval == 0 {
+		c.MaxReconnectInterval = 30 * time.Second
+	}
+	return c
 }
diff --git a/pkg/mcp/ide/ide.go b/pkg/mcp/ide/ide.go
index 64c4274..c4f7565 100644
--- a/pkg/mcp/ide/ide.go
+++ b/pkg/mcp/ide/ide.go
@@ -19,13 +19,12 @@ type Subsystem struct {
 	hub    *ws.Hub
 }
 
-// New creates an IDE subsystem. The ws.Hub is used for real-time forwarding;
-// pass nil if headless (tools still work but real-time streaming is disabled).
-func New(hub *ws.Hub, opts ...Option) *Subsystem {
-	cfg := DefaultConfig()
-	for _, opt := range opts {
-		opt(&cfg)
-	}
+// New creates an IDE subsystem from a Config DTO.
+//
+// The ws.Hub is used for real-time forwarding; pass nil if headless
+// (tools still work but real-time streaming is disabled).
+func New(hub *ws.Hub, cfg Config) *Subsystem {
+	cfg = cfg.WithDefaults()
 	var bridge *Bridge
 	if hub != nil {
 		bridge = NewBridge(hub, cfg)
diff --git a/pkg/mcp/ide/tools_test.go b/pkg/mcp/ide/tools_test.go
index 21a01fa..ae74eae 100644
--- a/pkg/mcp/ide/tools_test.go
+++ b/pkg/mcp/ide/tools_test.go
@@ -15,7 +15,7 @@ import (
 
 // newNilBridgeSubsystem returns a Subsystem with no hub/bridge (headless mode).
 func newNilBridgeSubsystem() *Subsystem {
-	return New(nil)
+	return New(nil, Config{})
 }
 
 // newConnectedSubsystem returns a Subsystem with a connected bridge and a
@@ -42,10 +42,10 @@ func newConnectedSubsystem(t *testing.T) (*Subsystem, context.CancelFunc, *httpt
 	ctx, cancel := context.WithCancel(context.Background())
 	go hub.Run(ctx)
 
-	sub := New(hub,
-		WithLaravelURL(wsURL(ts)),
-		WithReconnectInterval(50*time.Millisecond),
-	)
+	sub := New(hub, Config{
+		LaravelWSURL:      wsURL(ts),
+		ReconnectInterval: 50 * time.Millisecond,
+	})
 	sub.StartBridge(ctx)
 
 	waitConnected(t, sub.Bridge(), 2*time.Second)
@@ -690,7 +690,7 @@ func TestSubsystem_Good_RegisterTools(t *testing.T) {
 	// RegisterTools requires a real mcp.Server which is complex to construct
 	// in isolation. This test verifies the Subsystem can be created and
 	// the Bridge/Shutdown path works end-to-end.
-	sub := New(nil)
+	sub := New(nil, Config{})
 	if sub.Bridge() != nil {
 		t.Error("expected nil bridge with nil hub")
 	}
@@ -701,20 +701,20 @@ func TestSubsystem_Good_RegisterTools(t *testing.T) {
 
 // TestSubsystem_Good_StartBridgeNilHub verifies StartBridge is a no-op with nil hub.
 func TestSubsystem_Good_StartBridgeNilHub(t *testing.T) {
-	sub := New(nil)
+	sub := New(nil, Config{})
 	// Should not panic
 	sub.StartBridge(context.Background())
 }
 
-// TestSubsystem_Good_WithOptions verifies all config options apply correctly.
-func TestSubsystem_Good_WithOptions(t *testing.T) {
+// TestSubsystem_Good_WithConfig verifies the Config DTO applies correctly.
+func TestSubsystem_Good_WithConfig(t *testing.T) {
 	hub := ws.NewHub()
-	sub := New(hub,
-		WithLaravelURL("ws://custom:1234/ws"),
-		WithWorkspaceRoot("/tmp/test"),
-		WithReconnectInterval(5*time.Second),
-		WithToken("secret-123"),
-	)
+	sub := New(hub, Config{
+		LaravelWSURL:      "ws://custom:1234/ws",
+		WorkspaceRoot:     "/tmp/test",
+		ReconnectInterval: 5 * time.Second,
+		Token:             "secret-123",
+	})
 
 	if sub.cfg.LaravelWSURL != "ws://custom:1234/ws" {
 		t.Errorf("expected custom URL, got %q", sub.cfg.LaravelWSURL)
@@ -761,7 +761,10 @@ func TestChatSend_Good_BridgeMessageType(t *testing.T) {
 	ctx := t.Context()
 	go hub.Run(ctx)
 
-	sub := New(hub, WithLaravelURL(wsURL(ts)), WithReconnectInterval(50*time.Millisecond))
+	sub := New(hub, Config{
+		LaravelWSURL:      wsURL(ts),
+		ReconnectInterval: 50 * time.Millisecond,
+	})
 	sub.StartBridge(ctx)
 	waitConnected(t, sub.Bridge(), 2*time.Second)
 
diff --git a/pkg/mcp/mcp.go b/pkg/mcp/mcp.go
index 785fe9c..7541a20 100644
--- a/pkg/mcp/mcp.go
+++ b/pkg/mcp/mcp.go
@@ -9,6 +9,7 @@ import (
 	"iter"
 	"net/http"
 	"os"
+	"path/filepath"
 	"slices"
 	"sync"
 
@@ -93,10 +94,18 @@ func New(opts Options) (*Service, error) {
 	} else {
 		root := opts.WorkspaceRoot
 		if root == "" {
-			root = core.Env("DIR_CWD")
+			cwd, err := os.Getwd()
+			if err != nil {
+				return nil, core.E("mcp.New", "failed to get working directory", err)
+			}
+			root = cwd
 		}
-		s.workspaceRoot = root
-		m, merr := io.NewSandboxed(root)
+		abs, err := filepath.Abs(root)
+		if err != nil {
+			return nil, core.E("mcp.New", "failed to resolve workspace root", err)
+		}
+		s.workspaceRoot = abs
+		m, merr := io.NewSandboxed(abs)
 		if merr != nil {
 			return nil, core.E("mcp.New", "failed to create workspace medium", merr)
 		}
@@ -177,7 +186,6 @@ func (s *Service) Shutdown(ctx context.Context) error {
 	return nil
 }
 
-
 // WSHub returns the WebSocket hub, or nil if not configured.
 //
 //	if hub := svc.WSHub(); hub != nil {
@@ -423,8 +431,8 @@ type LanguageInfo struct {
 //	}
 type EditDiffInput struct {
 	Path       string `json:"path"`                  // e.g. "main.go"
-	OldString  string `json:"old_string"`             // text to find
-	NewString  string `json:"new_string"`             // replacement text
+	OldString  string `json:"old_string"`            // text to find
+	NewString  string `json:"new_string"`            // replacement text
 	ReplaceAll bool   `json:"replace_all,omitempty"` // replace all occurrences (default: first only)
 }
 
@@ -668,7 +676,6 @@ func (s *Service) Run(ctx context.Context) error {
 	})
 }
 
-
 // countOccurrences counts non-overlapping instances of substr in s.
 func countOccurrences(s, substr string) int {
 	if substr == "" {