prefab-sentinel
MCP server for safely inspecting and editing Unity/VRChat prefabs, scenes, and assets. It diagnoses override collisions, broken references, and runtime exceptions, with read-only YAML analysis and write operations via an Editor Bridge.
Caution. Specific findings reduced this grade. They are listed on the page. Grades reflect the full trust pyramid: code, verification depth, and reputation. New projects cap at C until adoption is earned.
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tyunta
Source: Glama
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The grade above is for the source repository. Registries can serve a different version, so we mark the ones we were not able to read.
These names and descriptions are the publisher's own, read from the source code. We print them as written. Our assessment is the findings above, not this list.
add_componentAdd a component to an existing GameObject in an open-mode asset.
remove_componentRemove a component from an existing GameObject in an open-mode asset.
copy_component_fieldsCopy serialized field values between components of the same type.
vrcsdk_uploadBuild and upload an avatar or world to VRChat via VRC SDK.
editor_reflectInspect Unity C# APIs via runtime reflection.
editor_inspect_animation_clipRead an AnimationClip's curves and timing (issue #243).
editor_create_animation_clipWrite a new AnimationClip (issue #243, issue #53).
editor_apply_animation_clipPreview-apply an AnimationClip against a live target (issue #243).
editor_create_emptyCreate an empty GameObject with name, optional parent and position.
editor_create_primitiveCreate a primitive GameObject (Cube, Sphere, Cylinder, Capsule, Plane, Quad).
editor_create_ui_elementCreate a uGUI element under the requested parent (issue #195).
editor_batch_createCreate multiple GameObjects in a single request (Undo-grouped).
editor_batch_set_propertySet multiple properties in a single request (Undo-grouped).
editor_batch_set_material_propertySet multiple shader properties on one material in a single request (Undo-grouped).
editor_batch_add_componentAdd components to multiple GameObjects in a single request (Undo-grouped).
editor_open_sceneOpen a Unity scene by asset path.
editor_save_sceneSave the current scene. If asset_path is empty, saves all open scenes in place.
editor_create_sceneCreate a new empty Unity scene and save it to the specified path.
editor_run_scriptRun an arbitrary C# snippet inside the Unity Editor.
editor_run_script_submitStage a C# snippet asynchronously and return an opaque request id (issue #233).
editor_run_script_pollPoll an asynchronous run-script job (issue #233).
editor_set_propertySet a serialized property on a component via Unity's SerializedObject API.
editor_set_propertiesSet multiple serialized properties on a live Unity Editor component in a single Undo group.
editor_safe_save_prefabSave a scene GameObject as a Prefab or Prefab Variant asset with optional strip-and-reattach protection for caller-named component types (issues #193, #228).
editor_set_parentSet the parent of a GameObject in the scene hierarchy (Undo-able).
editor_open_prefabOpen a prefab as the active Prefab Stage (issue #236).
editor_close_prefabClose the active Prefab Stage (issue #236).
editor_add_udonsharp_componentUpsert an UdonSharpBehaviour component on a GameObject.
editor_set_udonsharp_fieldWrite a single serialized field on the unique UdonSharp behaviour at *hierarchy_path*.
editor_wire_persistent_listenerWire a string-mode persistent listener from a UnityEvent to a method on another component.
editor_screenshotCapture a screenshot of the Unity Editor (issues #249, #84).
editor_force_scene_view_refreshBridge-side scene-view refresh primitive (issue #242).
editor_selectSelect a GameObject in the Unity Hierarchy.
editor_frameFrame the selected object in Scene view.
editor_get_cameraGet current Scene view camera state.
editor_set_cameraSet Scene view camera.
editor_list_childrenList children of a GameObject in the running scene.
editor_list_materialsList material slots on renderers under a GameObject at runtime.
editor_list_rootsList root GameObjects in the current Scene or Prefab Stage.
editor_get_material_propertyRead shader property values from a material at runtime.
editor_set_material_propertySet a shader property value on a material at runtime.
editor_consoleCapture Unity Console log entries as structured data.
editor_refreshRefresh the asset database and report any triggered compile.
editor_recompileRecompile scripts and synchronously wait for completion (issue #54).
editor_run_testsRun Unity integration tests via Editor Bridge.
editor_instantiateInstantiate a Prefab into the current Scene.
editor_set_materialReplace a material slot on a Renderer at runtime (Undo-able).
editor_find_renderers_by_materialFind all renderers using a specific material in the current scene.
editor_renameRename a GameObject in the scene (Undo-able).
editor_add_componentAdd a component to a GameObject at runtime (Undo-able).
editor_remove_componentRemove a component from a GameObject at runtime (Undo-able).
editor_create_udon_program_assetCreate an UdonSharpProgramAsset (.asset) for an UdonSharp C# script.
editor_deleteDelete a GameObject from the scene hierarchy (Undo-able).
editor_get_blend_shapesGet BlendShape names and weights, paginated (issue #241).
editor_set_blend_shapeSet a BlendShape weight by name on a SkinnedMeshRenderer (Undo-able).
editor_list_menu_itemsList Unity Editor menu items registered via [MenuItem] attribute.
editor_execute_menu_itemExecute a Unity Editor menu item by path.
set_material_propertySet a single property in a .mat file (offline YAML editing).
copy_assetCopy a Unity text asset with automatic m_Name sync and .meta generation.
rename_assetRename a Unity text asset with automatic m_Name sync and .meta rename.
patch_applyValidate and apply a patch plan to Unity assets.
revert_overridesRemove a specific property override from a Prefab Variant.
activate_projectSet the project scope and warm caches for subsequent requests.
deploy_bridgeDeploy or update Bridge C# files to the Unity project.
get_project_statusShow current session state: cached items, scope, project root.
set_propertySet a serialized field value on a component identified by symbol path.
set_propertiesSet multiple serialized property values on a component in a single transaction.
get_unity_symbolsGet the symbol tree (GameObject/Component hierarchy) of a Unity asset.
find_unity_symbolFind a Unity object by its human-readable symbol path.
find_referencing_assetsFind all assets that reference a given asset path or GUID.
validate_refsScan for broken GUID/fileID references in a Unity project scope.
inspect_wiringAnalyze MonoBehaviour field wiring in a Prefab or Scene.
inspect_variantInspect a Prefab Variant's override chain and effective values.
diff_unity_symbolsShow only the differences between a Variant and its Base.
list_serialized_fieldsList serialized C# fields for a Unity script.
validate_field_renameAnalyze the impact of renaming a serialized C# field (read-only).
check_field_coverageDetect unused C# fields or orphaned YAML propertyPaths in scope.
inspect_materialsShow per-renderer material slot assignments with override/inherited markers.
inspect_material_assetInspect shader, properties, and texture references in a .mat file.
validate_structureValidate internal YAML structure (fileID duplicates, Transform consistency).
inspect_hierarchyDisplay the GameObject hierarchy tree of a Unity asset.
validate_all_wiringScan all .prefab/.unity files in scope for null references.
validate_runtimeRun runtime validation: UdonSharp compile + ClientSim execution.
UNITYTOOL_PATCH_BRIDGETool annotations
No tools have read-only/destructive annotations
Add readOnlyHint or destructiveHint annotations to every tool so hosts can warn users before invoking.
All four hints declared on every tool
83/83 tools missing one or more hints — add_component (missing: readOnlyHint, destructiveHint, idempotentHint, openWorldHint); remove_component (missing: readOnlyHint, destructiveHint, idempotentHint, openWorldHint); copy_component_fields (missing: readOnlyHint, destructiveHint, idempotentHint, openWorldHint), +80 more. OpenAI's directory rejects tools where any of the four hints are missing or non-boolean.
For every tool, set all four hints (readOnlyHint, destructiveHint, idempotentHint, openWorldHint) to explicit true/false values that match the handler’s actual behaviour.
Destructive tools are labelled
1 tool perform destructive updates without destructiveHint — deploy_bridge deletes at line 211 (old_file.unlink())
Add destructiveHint:true to any tool whose handler calls .delete(), .upsert(), .update(), unlink, rm, DELETE, DROP, REPLACE INTO, or any operation that overwrites existing data.
Tool inputs are validated
78/83 tool handlers declare input schemas (94%)
Declare an inputSchema with zod/joi/yup on every tool definition.
Tool handlers catch errors
Only 5/83 tool handlers wrap calls in try/catch (6%)
Wrap each tool handler body in try/catch and return a structured error response.
Tests exist
No test files found
Add tests that exercise each declared tool.
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