fix(mcp): add safe type assertions and complete stub handlers

Replace all 32 unchecked type assertions (result.(Type)) with safe
ok-pattern checks that return descriptive errors on type mismatch.

Complete stub handlers in tools_window.go (restore, title, visibility,
fullscreen) and tools_layout.go (save, restore, list, delete, get,
tile, snap) using proper IPC message types instead of workarounds.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

pkg/mcp/mcp_test.go

@@ -48,7 +48,8 @@ func TestMCP_Good_ClipboardRoundTrip(t *testing.T) {
 	result, handled, err := c.QUERY(clipboard.QueryText{})
 	require.NoError(t, err)
 	assert.True(t, handled)
-	content, _ := result.(clipboard.ClipboardContent)
+	content, ok := result.(clipboard.ClipboardContent)
+	require.True(t, ok, "expected ClipboardContent type")
 	assert.Equal(t, "hello", content.Text)
 }
 

pkg/mcp/tools_clipboard.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/clipboard"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -20,7 +21,10 @@ func (s *Subsystem) clipboardRead(_ context.Context, _ *mcp.CallToolRequest, _ C
 	if err != nil {
 		return nil, ClipboardReadOutput{}, err
 	}
-	content, _ := result.(clipboard.ClipboardContent)
+	content, ok := result.(clipboard.ClipboardContent)
+	if !ok {
+		return nil, ClipboardReadOutput{}, fmt.Errorf("unexpected result type from clipboard read query")
+	}
 	return nil, ClipboardReadOutput{Content: content.Text}, nil
 }
 
@@ -38,7 +42,10 @@ func (s *Subsystem) clipboardWrite(_ context.Context, _ *mcp.CallToolRequest, in
 	if err != nil {
 		return nil, ClipboardWriteOutput{}, err
 	}
-	success, _ := result.(bool)
+	success, ok := result.(bool)
+	if !ok {
+		return nil, ClipboardWriteOutput{}, fmt.Errorf("unexpected result type from clipboard write task")
+	}
 	return nil, ClipboardWriteOutput{Success: success}, nil
 }
 
@@ -54,7 +61,10 @@ func (s *Subsystem) clipboardHas(_ context.Context, _ *mcp.CallToolRequest, _ Cl
 	if err != nil {
 		return nil, ClipboardHasOutput{}, err
 	}
-	content, _ := result.(clipboard.ClipboardContent)
+	content, ok := result.(clipboard.ClipboardContent)
+	if !ok {
+		return nil, ClipboardHasOutput{}, fmt.Errorf("unexpected result type from clipboard has query")
+	}
 	return nil, ClipboardHasOutput{HasContent: content.HasContent}, nil
 }
 
@@ -70,7 +80,10 @@ func (s *Subsystem) clipboardClear(_ context.Context, _ *mcp.CallToolRequest, _
 	if err != nil {
 		return nil, ClipboardClearOutput{}, err
 	}
-	success, _ := result.(bool)
+	success, ok := result.(bool)
+	if !ok {
+		return nil, ClipboardClearOutput{}, fmt.Errorf("unexpected result type from clipboard clear task")
+	}
 	return nil, ClipboardClearOutput{Success: success}, nil
 }
 

pkg/mcp/tools_contextmenu.go

@@ -4,6 +4,7 @@ package mcp
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/contextmenu"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -24,10 +25,15 @@ type ContextMenuAddOutput struct {
 
 func (s *Subsystem) contextMenuAdd(_ context.Context, _ *mcp.CallToolRequest, input ContextMenuAddInput) (*mcp.CallToolResult, ContextMenuAddOutput, error) {
 	// Convert map[string]any to ContextMenuDef via JSON round-trip
-	menuJSON, _ := json.Marshal(input.Menu)
+	menuJSON, err := json.Marshal(input.Menu)
+	if err != nil {
+		return nil, ContextMenuAddOutput{}, fmt.Errorf("failed to marshal menu definition: %w", err)
+	}
 	var menuDef contextmenu.ContextMenuDef
-	_ = json.Unmarshal(menuJSON, &menuDef)
-	_, _, err := s.core.PERFORM(contextmenu.TaskAdd{Name: input.Name, Menu: menuDef})
+	if err := json.Unmarshal(menuJSON, &menuDef); err != nil {
+		return nil, ContextMenuAddOutput{}, fmt.Errorf("failed to unmarshal menu definition: %w", err)
+	}
+	_, _, err = s.core.PERFORM(contextmenu.TaskAdd{Name: input.Name, Menu: menuDef})
 	if err != nil {
 		return nil, ContextMenuAddOutput{}, err
 	}
@@ -65,14 +71,22 @@ func (s *Subsystem) contextMenuGet(_ context.Context, _ *mcp.CallToolRequest, in
 	if err != nil {
 		return nil, ContextMenuGetOutput{}, err
 	}
-	menu, _ := result.(*contextmenu.ContextMenuDef)
+	menu, ok := result.(*contextmenu.ContextMenuDef)
+	if !ok {
+		return nil, ContextMenuGetOutput{}, fmt.Errorf("unexpected result type from context menu get query")
+	}
 	if menu == nil {
 		return nil, ContextMenuGetOutput{}, nil
 	}
 	// Convert to map[string]any via JSON round-trip to avoid cyclic type in schema
-	menuJSON, _ := json.Marshal(menu)
+	menuJSON, err := json.Marshal(menu)
+	if err != nil {
+		return nil, ContextMenuGetOutput{}, fmt.Errorf("failed to marshal context menu: %w", err)
+	}
 	var menuMap map[string]any
-	_ = json.Unmarshal(menuJSON, &menuMap)
+	if err := json.Unmarshal(menuJSON, &menuMap); err != nil {
+		return nil, ContextMenuGetOutput{}, fmt.Errorf("failed to unmarshal context menu: %w", err)
+	}
 	return nil, ContextMenuGetOutput{Menu: menuMap}, nil
 }
 
@@ -88,11 +102,19 @@ func (s *Subsystem) contextMenuList(_ context.Context, _ *mcp.CallToolRequest, _
 	if err != nil {
 		return nil, ContextMenuListOutput{}, err
 	}
-	menus, _ := result.(map[string]contextmenu.ContextMenuDef)
+	menus, ok := result.(map[string]contextmenu.ContextMenuDef)
+	if !ok {
+		return nil, ContextMenuListOutput{}, fmt.Errorf("unexpected result type from context menu list query")
+	}
 	// Convert to map[string]any via JSON round-trip to avoid cyclic type in schema
-	menusJSON, _ := json.Marshal(menus)
+	menusJSON, err := json.Marshal(menus)
+	if err != nil {
+		return nil, ContextMenuListOutput{}, fmt.Errorf("failed to marshal context menus: %w", err)
+	}
 	var menusMap map[string]any
-	_ = json.Unmarshal(menusJSON, &menusMap)
+	if err := json.Unmarshal(menusJSON, &menusMap); err != nil {
+		return nil, ContextMenuListOutput{}, fmt.Errorf("failed to unmarshal context menus: %w", err)
+	}
 	return nil, ContextMenuListOutput{Menus: menusMap}, nil
 }
 

pkg/mcp/tools_dialog.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/dialog"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -30,7 +31,10 @@ func (s *Subsystem) dialogOpenFile(_ context.Context, _ *mcp.CallToolRequest, in
 	if err != nil {
 		return nil, DialogOpenFileOutput{}, err
 	}
-	paths, _ := result.([]string)
+	paths, ok := result.([]string)
+	if !ok {
+		return nil, DialogOpenFileOutput{}, fmt.Errorf("unexpected result type from open file dialog")
+	}
 	return nil, DialogOpenFileOutput{Paths: paths}, nil
 }
 
@@ -56,7 +60,10 @@ func (s *Subsystem) dialogSaveFile(_ context.Context, _ *mcp.CallToolRequest, in
 	if err != nil {
 		return nil, DialogSaveFileOutput{}, err
 	}
-	path, _ := result.(string)
+	path, ok := result.(string)
+	if !ok {
+		return nil, DialogSaveFileOutput{}, fmt.Errorf("unexpected result type from save file dialog")
+	}
 	return nil, DialogSaveFileOutput{Path: path}, nil
 }
 
@@ -78,7 +85,10 @@ func (s *Subsystem) dialogOpenDirectory(_ context.Context, _ *mcp.CallToolReques
 	if err != nil {
 		return nil, DialogOpenDirectoryOutput{}, err
 	}
-	path, _ := result.(string)
+	path, ok := result.(string)
+	if !ok {
+		return nil, DialogOpenDirectoryOutput{}, fmt.Errorf("unexpected result type from open directory dialog")
+	}
 	return nil, DialogOpenDirectoryOutput{Path: path}, nil
 }
 
@@ -103,7 +113,10 @@ func (s *Subsystem) dialogConfirm(_ context.Context, _ *mcp.CallToolRequest, inp
 	if err != nil {
 		return nil, DialogConfirmOutput{}, err
 	}
-	button, _ := result.(string)
+	button, ok := result.(string)
+	if !ok {
+		return nil, DialogConfirmOutput{}, fmt.Errorf("unexpected result type from confirm dialog")
+	}
 	return nil, DialogConfirmOutput{Button: button}, nil
 }
 
@@ -127,7 +140,10 @@ func (s *Subsystem) dialogPrompt(_ context.Context, _ *mcp.CallToolRequest, inpu
 	if err != nil {
 		return nil, DialogPromptOutput{}, err
 	}
-	button, _ := result.(string)
+	button, ok := result.(string)
+	if !ok {
+		return nil, DialogPromptOutput{}, fmt.Errorf("unexpected result type from prompt dialog")
+	}
 	return nil, DialogPromptOutput{Button: button}, nil
 }
 

pkg/mcp/tools_environment.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/environment"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -20,7 +21,10 @@ func (s *Subsystem) themeGet(_ context.Context, _ *mcp.CallToolRequest, _ ThemeG
 	if err != nil {
 		return nil, ThemeGetOutput{}, err
 	}
-	theme, _ := result.(environment.ThemeInfo)
+	theme, ok := result.(environment.ThemeInfo)
+	if !ok {
+		return nil, ThemeGetOutput{}, fmt.Errorf("unexpected result type from theme query")
+	}
 	return nil, ThemeGetOutput{Theme: theme}, nil
 }
 
@@ -36,7 +40,10 @@ func (s *Subsystem) themeSystem(_ context.Context, _ *mcp.CallToolRequest, _ The
 	if err != nil {
 		return nil, ThemeSystemOutput{}, err
 	}
-	info, _ := result.(environment.EnvironmentInfo)
+	info, ok := result.(environment.EnvironmentInfo)
+	if !ok {
+		return nil, ThemeSystemOutput{}, fmt.Errorf("unexpected result type from environment info query")
+	}
 	return nil, ThemeSystemOutput{Info: info}, nil
 }
 

pkg/mcp/tools_layout.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/window"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -18,13 +19,10 @@ type LayoutSaveOutput struct {
 }
 
 func (s *Subsystem) layoutSave(_ context.Context, _ *mcp.CallToolRequest, input LayoutSaveInput) (*mcp.CallToolResult, LayoutSaveOutput, error) {
-	// Save current window arrangement as a named layout.
-	// This delegates through IPC to the display orchestrator's SaveLayout method.
-	result, _, err := s.core.QUERY(window.QueryWindowList{})
+	_, _, err := s.core.PERFORM(window.TaskSaveLayout{Name: input.Name})
 	if err != nil {
 		return nil, LayoutSaveOutput{}, err
 	}
-	_ = result // Layout saving is coordinated by the display orchestrator
 	return nil, LayoutSaveOutput{Success: true}, nil
 }
 
@@ -38,6 +36,10 @@ type LayoutRestoreOutput struct {
 }
 
 func (s *Subsystem) layoutRestore(_ context.Context, _ *mcp.CallToolRequest, input LayoutRestoreInput) (*mcp.CallToolResult, LayoutRestoreOutput, error) {
+	_, _, err := s.core.PERFORM(window.TaskRestoreLayout{Name: input.Name})
+	if err != nil {
+		return nil, LayoutRestoreOutput{}, err
+	}
 	return nil, LayoutRestoreOutput{Success: true}, nil
 }
 
@@ -49,7 +51,15 @@ type LayoutListOutput struct {
 }
 
 func (s *Subsystem) layoutList(_ context.Context, _ *mcp.CallToolRequest, _ LayoutListInput) (*mcp.CallToolResult, LayoutListOutput, error) {
-	return nil, LayoutListOutput{}, nil
+	result, _, err := s.core.QUERY(window.QueryLayoutList{})
+	if err != nil {
+		return nil, LayoutListOutput{}, err
+	}
+	layouts, ok := result.([]window.LayoutInfo)
+	if !ok {
+		return nil, LayoutListOutput{}, fmt.Errorf("unexpected result type from layout list query")
+	}
+	return nil, LayoutListOutput{Layouts: layouts}, nil
 }
 
 // --- layout_delete ---
@@ -62,6 +72,10 @@ type LayoutDeleteOutput struct {
 }
 
 func (s *Subsystem) layoutDelete(_ context.Context, _ *mcp.CallToolRequest, input LayoutDeleteInput) (*mcp.CallToolResult, LayoutDeleteOutput, error) {
+	_, _, err := s.core.PERFORM(window.TaskDeleteLayout{Name: input.Name})
+	if err != nil {
+		return nil, LayoutDeleteOutput{}, err
+	}
 	return nil, LayoutDeleteOutput{Success: true}, nil
 }
 
@@ -75,7 +89,15 @@ type LayoutGetOutput struct {
 }
 
 func (s *Subsystem) layoutGet(_ context.Context, _ *mcp.CallToolRequest, input LayoutGetInput) (*mcp.CallToolResult, LayoutGetOutput, error) {
-	return nil, LayoutGetOutput{}, nil
+	result, _, err := s.core.QUERY(window.QueryLayoutGet{Name: input.Name})
+	if err != nil {
+		return nil, LayoutGetOutput{}, err
+	}
+	layout, ok := result.(*window.Layout)
+	if !ok {
+		return nil, LayoutGetOutput{}, fmt.Errorf("unexpected result type from layout get query")
+	}
+	return nil, LayoutGetOutput{Layout: layout}, nil
 }
 
 // --- layout_tile ---
@@ -89,6 +111,10 @@ type LayoutTileOutput struct {
 }
 
 func (s *Subsystem) layoutTile(_ context.Context, _ *mcp.CallToolRequest, input LayoutTileInput) (*mcp.CallToolResult, LayoutTileOutput, error) {
+	_, _, err := s.core.PERFORM(window.TaskTileWindows{Mode: input.Mode, Windows: input.Windows})
+	if err != nil {
+		return nil, LayoutTileOutput{}, err
+	}
 	return nil, LayoutTileOutput{Success: true}, nil
 }
 
@@ -103,6 +129,10 @@ type LayoutSnapOutput struct {
 }
 
 func (s *Subsystem) layoutSnap(_ context.Context, _ *mcp.CallToolRequest, input LayoutSnapInput) (*mcp.CallToolResult, LayoutSnapOutput, error) {
+	_, _, err := s.core.PERFORM(window.TaskSnapWindow{Name: input.Name, Position: input.Position})
+	if err != nil {
+		return nil, LayoutSnapOutput{}, err
+	}
 	return nil, LayoutSnapOutput{Success: true}, nil
 }
 

pkg/mcp/tools_notification.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/notification"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -43,7 +44,10 @@ func (s *Subsystem) notificationPermissionRequest(_ context.Context, _ *mcp.Call
 	if err != nil {
 		return nil, NotificationPermissionRequestOutput{}, err
 	}
-	granted, _ := result.(bool)
+	granted, ok := result.(bool)
+	if !ok {
+		return nil, NotificationPermissionRequestOutput{}, fmt.Errorf("unexpected result type from notification permission request")
+	}
 	return nil, NotificationPermissionRequestOutput{Granted: granted}, nil
 }
 
@@ -59,7 +63,10 @@ func (s *Subsystem) notificationPermissionCheck(_ context.Context, _ *mcp.CallTo
 	if err != nil {
 		return nil, NotificationPermissionCheckOutput{}, err
 	}
-	status, _ := result.(notification.PermissionStatus)
+	status, ok := result.(notification.PermissionStatus)
+	if !ok {
+		return nil, NotificationPermissionCheckOutput{}, fmt.Errorf("unexpected result type from notification permission check")
+	}
 	return nil, NotificationPermissionCheckOutput{Granted: status.Granted}, nil
 }
 

pkg/mcp/tools_screen.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/screen"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -20,7 +21,10 @@ func (s *Subsystem) screenList(_ context.Context, _ *mcp.CallToolRequest, _ Scre
 	if err != nil {
 		return nil, ScreenListOutput{}, err
 	}
-	screens, _ := result.([]screen.Screen)
+	screens, ok := result.([]screen.Screen)
+	if !ok {
+		return nil, ScreenListOutput{}, fmt.Errorf("unexpected result type from screen list query")
+	}
 	return nil, ScreenListOutput{Screens: screens}, nil
 }
 
@@ -38,7 +42,10 @@ func (s *Subsystem) screenGet(_ context.Context, _ *mcp.CallToolRequest, input S
 	if err != nil {
 		return nil, ScreenGetOutput{}, err
 	}
-	scr, _ := result.(*screen.Screen)
+	scr, ok := result.(*screen.Screen)
+	if !ok {
+		return nil, ScreenGetOutput{}, fmt.Errorf("unexpected result type from screen get query")
+	}
 	return nil, ScreenGetOutput{Screen: scr}, nil
 }
 
@@ -54,7 +61,10 @@ func (s *Subsystem) screenPrimary(_ context.Context, _ *mcp.CallToolRequest, _ S
 	if err != nil {
 		return nil, ScreenPrimaryOutput{}, err
 	}
-	scr, _ := result.(*screen.Screen)
+	scr, ok := result.(*screen.Screen)
+	if !ok {
+		return nil, ScreenPrimaryOutput{}, fmt.Errorf("unexpected result type from screen primary query")
+	}
 	return nil, ScreenPrimaryOutput{Screen: scr}, nil
 }
 
@@ -73,7 +83,10 @@ func (s *Subsystem) screenAtPoint(_ context.Context, _ *mcp.CallToolRequest, inp
 	if err != nil {
 		return nil, ScreenAtPointOutput{}, err
 	}
-	scr, _ := result.(*screen.Screen)
+	scr, ok := result.(*screen.Screen)
+	if !ok {
+		return nil, ScreenAtPointOutput{}, fmt.Errorf("unexpected result type from screen at point query")
+	}
 	return nil, ScreenAtPointOutput{Screen: scr}, nil
 }
 
@@ -89,7 +102,10 @@ func (s *Subsystem) screenWorkAreas(_ context.Context, _ *mcp.CallToolRequest, _
 	if err != nil {
 		return nil, ScreenWorkAreasOutput{}, err
 	}
-	areas, _ := result.([]screen.Rect)
+	areas, ok := result.([]screen.Rect)
+	if !ok {
+		return nil, ScreenWorkAreasOutput{}, fmt.Errorf("unexpected result type from screen work areas query")
+	}
 	return nil, ScreenWorkAreasOutput{WorkAreas: areas}, nil
 }
 

pkg/mcp/tools_tray.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/systray"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -67,7 +68,10 @@ func (s *Subsystem) trayInfo(_ context.Context, _ *mcp.CallToolRequest, _ TrayIn
 	if err != nil {
 		return nil, TrayInfoOutput{}, err
 	}
-	config, _ := result.(map[string]any)
+	config, ok := result.(map[string]any)
+	if !ok {
+		return nil, TrayInfoOutput{}, fmt.Errorf("unexpected result type from tray config query")
+	}
 	return nil, TrayInfoOutput{Config: config}, nil
 }
 

pkg/mcp/tools_webview.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/webview"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -102,7 +103,10 @@ func (s *Subsystem) webviewScreenshot(_ context.Context, _ *mcp.CallToolRequest,
 	if err != nil {
 		return nil, WebviewScreenshotOutput{}, err
 	}
-	sr, _ := result.(webview.ScreenshotResult)
+	sr, ok := result.(webview.ScreenshotResult)
+	if !ok {
+		return nil, WebviewScreenshotOutput{}, fmt.Errorf("unexpected result type from webview screenshot")
+	}
 	return nil, WebviewScreenshotOutput{Base64: sr.Base64, MimeType: sr.MimeType}, nil
 }
 
@@ -242,7 +246,10 @@ func (s *Subsystem) webviewConsole(_ context.Context, _ *mcp.CallToolRequest, in
 	if err != nil {
 		return nil, WebviewConsoleOutput{}, err
 	}
-	msgs, _ := result.([]webview.ConsoleMessage)
+	msgs, ok := result.([]webview.ConsoleMessage)
+	if !ok {
+		return nil, WebviewConsoleOutput{}, fmt.Errorf("unexpected result type from webview console query")
+	}
 	return nil, WebviewConsoleOutput{Messages: msgs}, nil
 }
 
@@ -280,7 +287,10 @@ func (s *Subsystem) webviewQuery(_ context.Context, _ *mcp.CallToolRequest, inpu
 	if err != nil {
 		return nil, WebviewQueryOutput{}, err
 	}
-	el, _ := result.(*webview.ElementInfo)
+	el, ok := result.(*webview.ElementInfo)
+	if !ok {
+		return nil, WebviewQueryOutput{}, fmt.Errorf("unexpected result type from webview query")
+	}
 	return nil, WebviewQueryOutput{Element: el}, nil
 }
 
@@ -300,7 +310,10 @@ func (s *Subsystem) webviewQueryAll(_ context.Context, _ *mcp.CallToolRequest, i
 	if err != nil {
 		return nil, WebviewQueryAllOutput{}, err
 	}
-	els, _ := result.([]*webview.ElementInfo)
+	els, ok := result.([]*webview.ElementInfo)
+	if !ok {
+		return nil, WebviewQueryAllOutput{}, fmt.Errorf("unexpected result type from webview query all")
+	}
 	return nil, WebviewQueryAllOutput{Elements: els}, nil
 }
 
@@ -320,7 +333,10 @@ func (s *Subsystem) webviewDOMTree(_ context.Context, _ *mcp.CallToolRequest, in
 	if err != nil {
 		return nil, WebviewDOMTreeOutput{}, err
 	}
-	html, _ := result.(string)
+	html, ok := result.(string)
+	if !ok {
+		return nil, WebviewDOMTreeOutput{}, fmt.Errorf("unexpected result type from webview DOM tree query")
+	}
 	return nil, WebviewDOMTreeOutput{HTML: html}, nil
 }
 
@@ -339,7 +355,10 @@ func (s *Subsystem) webviewURL(_ context.Context, _ *mcp.CallToolRequest, input
 	if err != nil {
 		return nil, WebviewURLOutput{}, err
 	}
-	url, _ := result.(string)
+	url, ok := result.(string)
+	if !ok {
+		return nil, WebviewURLOutput{}, fmt.Errorf("unexpected result type from webview URL query")
+	}
 	return nil, WebviewURLOutput{URL: url}, nil
 }
 
@@ -358,7 +377,10 @@ func (s *Subsystem) webviewTitle(_ context.Context, _ *mcp.CallToolRequest, inpu
 	if err != nil {
 		return nil, WebviewTitleOutput{}, err
 	}
-	title, _ := result.(string)
+	title, ok := result.(string)
+	if !ok {
+		return nil, WebviewTitleOutput{}, fmt.Errorf("unexpected result type from webview title query")
+	}
 	return nil, WebviewTitleOutput{Title: title}, nil
 }
 

pkg/mcp/tools_window.go

@@ -3,6 +3,7 @@ package mcp
 
 import (
 	"context"
+	"fmt"
 
 	"forge.lthn.ai/core/gui/pkg/window"
 	"github.com/modelcontextprotocol/go-sdk/mcp"
@@ -20,7 +21,10 @@ func (s *Subsystem) windowList(_ context.Context, _ *mcp.CallToolRequest, _ Wind
 	if err != nil {
 		return nil, WindowListOutput{}, err
 	}
-	windows, _ := result.([]window.WindowInfo)
+	windows, ok := result.([]window.WindowInfo)
+	if !ok {
+		return nil, WindowListOutput{}, fmt.Errorf("unexpected result type from window list query")
+	}
 	return nil, WindowListOutput{Windows: windows}, nil
 }
 
@@ -38,7 +42,10 @@ func (s *Subsystem) windowGet(_ context.Context, _ *mcp.CallToolRequest, input W
 	if err != nil {
 		return nil, WindowGetOutput{}, err
 	}
-	info, _ := result.(*window.WindowInfo)
+	info, ok := result.(*window.WindowInfo)
+	if !ok {
+		return nil, WindowGetOutput{}, fmt.Errorf("unexpected result type from window get query")
+	}
 	return nil, WindowGetOutput{Window: info}, nil
 }
 
@@ -54,7 +61,10 @@ func (s *Subsystem) windowFocused(_ context.Context, _ *mcp.CallToolRequest, _ W
 	if err != nil {
 		return nil, WindowFocusedOutput{}, err
 	}
-	windows, _ := result.([]window.WindowInfo)
+	windows, ok := result.([]window.WindowInfo)
+	if !ok {
+		return nil, WindowFocusedOutput{}, fmt.Errorf("unexpected result type from window list query")
+	}
 	for _, w := range windows {
 		if w.Focused {
 			return nil, WindowFocusedOutput{Window: w.Name}, nil
@@ -98,7 +108,10 @@ func (s *Subsystem) windowCreate(_ context.Context, _ *mcp.CallToolRequest, inpu
 	if err != nil {
 		return nil, WindowCreateOutput{}, err
 	}
-	info, _ := result.(window.WindowInfo)
+	info, ok := result.(window.WindowInfo)
+	if !ok {
+		return nil, WindowCreateOutput{}, fmt.Errorf("unexpected result type from window create task")
+	}
 	return nil, WindowCreateOutput{Window: info}, nil
 }
 
@@ -226,8 +239,7 @@ type WindowRestoreOutput struct {
 }
 
 func (s *Subsystem) windowRestore(_ context.Context, _ *mcp.CallToolRequest, input WindowRestoreInput) (*mcp.CallToolResult, WindowRestoreOutput, error) {
-	// Restore uses TaskFocus as a workaround (no dedicated restore task yet)
-	_, _, err := s.core.PERFORM(window.TaskFocus{Name: input.Name})
+	_, _, err := s.core.PERFORM(window.TaskRestore{Name: input.Name})
 	if err != nil {
 		return nil, WindowRestoreOutput{}, err
 	}
@@ -262,8 +274,7 @@ type WindowTitleOutput struct {
 }
 
 func (s *Subsystem) windowTitle(_ context.Context, _ *mcp.CallToolRequest, input WindowTitleInput) (*mcp.CallToolResult, WindowTitleOutput, error) {
-	// No dedicated IPC task for title change; use query to verify window exists
-	_, _, err := s.core.QUERY(window.QueryWindowByName{Name: input.Name})
+	_, _, err := s.core.PERFORM(window.TaskSetTitle{Name: input.Name, Title: input.Title})
 	if err != nil {
 		return nil, WindowTitleOutput{}, err
 	}
@@ -281,12 +292,9 @@ type WindowVisibilityOutput struct {
 }
 
 func (s *Subsystem) windowVisibility(_ context.Context, _ *mcp.CallToolRequest, input WindowVisibilityInput) (*mcp.CallToolResult, WindowVisibilityOutput, error) {
-	// Visibility uses focus/close as approximation (no dedicated visibility task yet)
-	if input.Visible {
-		_, _, err := s.core.PERFORM(window.TaskFocus{Name: input.Name})
-		if err != nil {
-			return nil, WindowVisibilityOutput{}, err
-		}
+	_, _, err := s.core.PERFORM(window.TaskSetVisibility{Name: input.Name, Visible: input.Visible})
+	if err != nil {
+		return nil, WindowVisibilityOutput{}, err
 	}
 	return nil, WindowVisibilityOutput{Success: true}, nil
 }
@@ -302,12 +310,9 @@ type WindowFullscreenOutput struct {
 }
 
 func (s *Subsystem) windowFullscreen(_ context.Context, _ *mcp.CallToolRequest, input WindowFullscreenInput) (*mcp.CallToolResult, WindowFullscreenOutput, error) {
-	// No dedicated fullscreen task in IPC yet; use maximise as approximation
-	if input.Fullscreen {
-		_, _, err := s.core.PERFORM(window.TaskMaximise{Name: input.Name})
-		if err != nil {
-			return nil, WindowFullscreenOutput{}, err
-		}
+	_, _, err := s.core.PERFORM(window.TaskFullscreen{Name: input.Name, Fullscreen: input.Fullscreen})
+	if err != nil {
+		return nil, WindowFullscreenOutput{}, err
 	}
 	return nil, WindowFullscreenOutput{Success: true}, nil
 }