Feat/optional physics screencapture modules

MCPForUnity/Editor/Helpers/ComponentOps.cs

@@ -376,6 +376,9 @@ internal static FieldInfo FindSerializedFieldInHierarchy(Type type, string field
 
         private static string CheckPhysicsConflict(GameObject target, Type componentType)
         {
+            // A 2D-vs-3D conflict is only possible when both physics modules are installed;
+            // if either is absent, its component types can't exist, so there's nothing to check.
+#if MCP_HAS_PHYSICS && MCP_HAS_PHYSICS_2D
             bool isAdding2DPhysics =
                 typeof(Rigidbody2D).IsAssignableFrom(componentType) ||
                 typeof(Collider2D).IsAssignableFrom(componentType);
@@ -398,6 +401,7 @@ private static string CheckPhysicsConflict(GameObject target, Type componentType
                     return $"Cannot add 3D physics component '{componentType.Name}' because the GameObject '{target.name}' already has a 2D Rigidbody or Collider.";
                 }
             }
+#endif
 
             return null;
         }

MCPForUnity/Editor/Helpers/GameObjectSerializer.cs

@@ -528,13 +528,15 @@ public static object GetComponentData(Component c, bool includeNonPublicSerializ
                 }
                 // --- End Skip Transform Properties ---
 
+#if MCP_HAS_PHYSICS
                 // --- Skip Collider properties that cause native crashes via PhysX ---
                 if (typeof(Collider).IsAssignableFrom(componentType) &&
                     propName == "GeometryHolder")
                 {
                     skipProperty = true;
                 }
                 // --- End Skip Collider Properties ---
+#endif
 
                 // Skip if flagged
                 if (skipProperty)

MCPForUnity/Editor/MCPForUnity.Editor.asmdef

@@ -19,6 +19,21 @@
             "name": "com.unity.visualeffectgraph",
             "expression": "0.0.0",
             "define": "UNITY_VFX_GRAPH"
+        },
+        {
+            "name": "com.unity.modules.physics",
+            "expression": "1.0.0",
+            "define": "MCP_HAS_PHYSICS"
+        },
+        {
+            "name": "com.unity.modules.physics2d",
+            "expression": "1.0.0",
+            "define": "MCP_HAS_PHYSICS_2D"
+        },
+        {
+            "name": "com.unity.modules.screencapture",
+            "expression": "1.0.0",
+            "define": "MCP_HAS_SCREEN_CAPTURE"
         }
     ],
     "noEngineReferences": false

MCPForUnity/Editor/Tools/GameObjects/GameObjectComponentHelpers.cs

@@ -32,6 +32,9 @@ internal static object AddComponentInternal(GameObject targetGo, string typeName
                 return new ErrorResponse("Cannot add another Transform component.");
             }
 
+            // A 2D-vs-3D conflict is only possible when both physics modules are installed;
+            // if either is absent, its component types can't exist, so there's nothing to check.
+#if MCP_HAS_PHYSICS && MCP_HAS_PHYSICS_2D
             bool isAdding2DPhysics = typeof(Rigidbody2D).IsAssignableFrom(componentType) || typeof(Collider2D).IsAssignableFrom(componentType);
             bool isAdding3DPhysics = typeof(Rigidbody).IsAssignableFrom(componentType) || typeof(Collider).IsAssignableFrom(componentType);
 
@@ -49,6 +52,7 @@ internal static object AddComponentInternal(GameObject targetGo, string typeName
                     return new ErrorResponse($"Cannot add 3D physics component '{typeName}' because the GameObject '{targetGo.name}' already has a 2D Rigidbody or Collider.");
                 }
             }
+#endif
 
             Component existingComponent = targetGo.GetComponent(componentType);
             if (existingComponent != null && !AllowsMultiple(componentType))

MCPForUnity/Editor/Tools/ManageAsset.cs

@@ -10,13 +10,15 @@
 using MCPForUnity.Editor.Tools;
 using MCPForUnity.Runtime.Helpers;
 
+#if MCP_HAS_PHYSICS
 #if UNITY_6000_0_OR_NEWER
 using PhysicsMaterialType = UnityEngine.PhysicsMaterial;
 using PhysicsMaterialCombine = UnityEngine.PhysicsMaterialCombine;
 #else
 using PhysicsMaterialType = UnityEngine.PhysicMaterial;
 using PhysicsMaterialCombine = UnityEngine.PhysicMaterialCombine;
 #endif
+#endif
 
 namespace MCPForUnity.Editor.Tools
 {
@@ -224,11 +226,17 @@ private static object CreateAsset(JObject @params)
                 }
                 else if (lowerAssetType == "physicsmaterial")
                 {
+#if MCP_HAS_PHYSICS
                     PhysicsMaterialType pmat = new PhysicsMaterialType();
                     if (properties != null)
                         ApplyPhysicsMaterialProperties(pmat, properties);
                     AssetDatabase.CreateAsset(pmat, fullPath);
                     newAsset = pmat;
+#else
+                    return new ErrorResponse(
+                        "Cannot create a PhysicsMaterial: the Physics module (com.unity.modules.physics) is not installed. "
+                        + "Enable it via Window > Package Manager > Built-in > Physics.");
+#endif
                 }
                 else if (lowerAssetType == "prefab")
                 {
@@ -876,6 +884,7 @@ private static void EnsureDirectoryExists(string directoryPath)
 
 
 
+#if MCP_HAS_PHYSICS
         /// <summary>
         ///  Applies properties from JObject to a PhysicsMaterial.
         /// </summary>
@@ -946,6 +955,7 @@ private static bool ApplyPhysicsMaterialProperties(PhysicsMaterialType pmat, JOb
 
             return modified;
         }
+#endif
 
         /// <summary>
         /// Generic helper to set properties on any UnityEngine.Object using reflection.

MCPForUnity/Editor/Tools/ManageScene.cs

@@ -1460,8 +1460,9 @@ private static bool TryGetRendererBounds(GameObject target, out Bounds bounds)
         private static bool TryGetColliderBounds(GameObject target, out Bounds bounds)
         {
             bounds = default(Bounds);
-            var colliders = target.GetComponentsInChildren<Collider>(true);
             bool hasBounds = false;
+#if MCP_HAS_PHYSICS
+            var colliders = target.GetComponentsInChildren<Collider>(true);
             foreach (var collider in colliders)
             {
                 if (collider == null || !collider.gameObject.activeInHierarchy)
@@ -1477,7 +1478,9 @@ private static bool TryGetColliderBounds(GameObject target, out Bounds bounds)
                     bounds.Encapsulate(collider.bounds);
                 }
             }
+#endif
 
+#if MCP_HAS_PHYSICS_2D
             var colliders2D = target.GetComponentsInChildren<Collider2D>(true);
             foreach (var collider in colliders2D)
             {
@@ -1494,6 +1497,7 @@ private static bool TryGetColliderBounds(GameObject target, out Bounds bounds)
                     bounds.Encapsulate(collider.bounds);
                 }
             }
+#endif
 
             return hasBounds;
         }

MCPForUnity/Editor/Tools/ManageUI.cs

@@ -811,10 +811,12 @@ private static object SerializeVisualElement(VisualElement element, int depth, i
 
         // Play-mode coroutine capture state.  Only one capture is in-flight at a
         // time; concurrent render_ui calls while a capture is pending are rejected
-        // with an explicit error.
+        // with an explicit error.  Only used when the Screen Capture module is present.
+#if MCP_HAS_SCREEN_CAPTURE
         private static Texture2D s_pendingCaptureTex;
         private static bool s_pendingCaptureDone;
         private static bool s_pendingCaptureStarted;
+#endif
 
         private static object RenderUI(JObject @params)
         {
@@ -854,6 +856,7 @@ private static object RenderUI(JObject @params)
             // Second call: result is ready – save PNG and return data.
             if (Application.isPlaying)
             {
+#if MCP_HAS_SCREEN_CAPTURE
                 // Build the output paths (used by both the pending and ready branches)
                 string resolvedPlayName = string.IsNullOrWhiteSpace(fileName)
                     ? $"ui-render-{DateTime.Now:yyyyMMdd-HHmmss}.png"
@@ -954,6 +957,12 @@ private static object RenderUI(JObject @params)
                         { "gameObject", (object)target ?? uxmlPath },
                         { "note", "A screen capture was scheduled for the end of this frame. Call render_ui once more to get the result." }
                     });
+#else
+                return new ErrorResponse(
+                    "Play-mode UI capture requires the Screen Capture module (com.unity.modules.screencapture), " +
+                    "which is not installed. Enable it via Window > Package Manager > Built-in > Screen Capture, " +
+                    "or render the UI outside Play mode (which captures via a RenderTexture instead).");
+#endif
             }
             // ── End play-mode branch ────────────────────────────────────────────────
 

MCPForUnity/Editor/Tools/Physics/CollisionMatrixOps.cs

@@ -16,6 +16,19 @@ public static object GetCollisionMatrix(JObject @params)
             if (dimension != "3d" && dimension != "2d")
                 return new ErrorResponse($"Invalid dimension: '{dimension}'. Use '3d' or '2d'.");
 
+            if (dimension == "2d")
+            {
+#if !MCP_HAS_PHYSICS_2D
+                return new ErrorResponse("Physics 2D module (com.unity.modules.physics2d) is not installed.");
+#endif
+            }
+            else
+            {
+#if !MCP_HAS_PHYSICS
+                return new ErrorResponse("Physics module (com.unity.modules.physics) is not installed.");
+#endif
+            }
+
             var layers = new List<object>();
             var populatedIndices = new List<int>();
 
@@ -38,9 +51,23 @@ public static object GetCollisionMatrix(JObject @params)
                 {
                     if (j > i) continue;
                     string nameB = LayerMask.LayerToName(j);
-                    bool collides = dimension == "2d"
-                        ? !Physics2D.GetIgnoreLayerCollision(i, j)
-                        : !UnityEngine.Physics.GetIgnoreLayerCollision(i, j);
+                    bool collides;
+                    if (dimension == "2d")
+                    {
+#if MCP_HAS_PHYSICS_2D
+                        collides = !Physics2D.GetIgnoreLayerCollision(i, j);
+#else
+                        return new ErrorResponse("Physics 2D module (com.unity.modules.physics2d) is not installed.");
+#endif
+                    }
+                    else
+                    {
+#if MCP_HAS_PHYSICS
+                        collides = !UnityEngine.Physics.GetIgnoreLayerCollision(i, j);
+#else
+                        return new ErrorResponse("Physics module (com.unity.modules.physics) is not installed.");
+#endif
+                    }
                     row[nameB] = collides;
                 }
 
@@ -83,13 +110,21 @@ public static object SetCollisionMatrix(JObject @params)
 
             if (dimension == "2d")
             {
+#if MCP_HAS_PHYSICS_2D
                 Physics2D.IgnoreLayerCollision(layerA, layerB, !collide);
                 MarkSettingsDirty("ProjectSettings/Physics2DSettings.asset");
+#else
+                return new ErrorResponse("Physics 2D module (com.unity.modules.physics2d) is not installed.");
+#endif
             }
             else
             {
+#if MCP_HAS_PHYSICS
                 UnityEngine.Physics.IgnoreLayerCollision(layerA, layerB, !collide);
                 MarkSettingsDirty("ProjectSettings/DynamicsManager.asset");
+#else
+                return new ErrorResponse("Physics module (com.unity.modules.physics) is not installed.");
+#endif
             }
 
             string nameA = LayerMask.LayerToName(layerA);