Overview The Summer Engine MCP server exposes 23 tools in three categories: Scene (10), Debug (9), and Project (4). All tools require the engine to be running with a project open. If the engine isn’t running, tools return a clear error message.
Critical: Value formats. Properties like position, rotation_degrees, and mesh use engine string syntax, not raw JSON objects. See Value Formats below.When setting properties via summer_set_prop or summer_set_resource_property, use these formats:
Type Format Example Vector3 "Vector3(x, y, z)""Vector3(0, 10, 0)"Vector2 "Vector2(x, y)""Vector2(100, 200)"Color "Color(r, g, b, a)" RGBA 0.0 to 1.0"Color(1, 0.5, 0, 1)"Transform3D "Transform3D(...)" basis + origin"Transform3D(1,0,0, 0,1,0, 0,0,1, 0,5,0)"Resource Class name, auto-instantiated "BoxMesh", "SphereMesh", "StandardMaterial3D"Number Native JSON 1.5, 42Boolean Native JSON true, falseString Native JSON "hello"
Wrong: "position": {x: 0, y: 10, z: 0} stays Dictionary, failsRight: "position": "Vector3(0, 10, 0)" parses to Vector3
summer_add_node Add a new node to the scene tree.
Parameter Type Required Description parentstring Yes Parent path, e.g. ./World or ./World/Enemies typestring Yes Node type, e.g. MeshInstance3D, CharacterBody3D namestring Yes Name for the new node
Common node types: Node3D, MeshInstance3D, CharacterBody3D, Camera3D, DirectionalLight3D, CollisionShape3D, Area3D, Node2D, Sprite2D, Control, Button, VBoxContainer, AudioStreamPlayer.Example: summer_add_node(parent="./", type="DirectionalLight3D", name="Sun")summer_set_prop Set a property on a node. Primary way to configure nodes after adding them.
Parameter Type Required Description pathstring Yes Node path, e.g. ./World/Player keystring Yes Property name, e.g. position, mesh, visible valuestring | number | boolean Yes Value in engine string format for complex types
Common properties: position, rotation_degrees, scale, visible, mesh, shadow_enabled, light_energy, fov.Example: summer_set_prop(path="./World/Player", key="position", value="Vector3(0, 1, 0)")summer_set_resource_property Set a nested property on a resource attached to a node (e.g., shape size, material color).
Parameter Type Required Description nodePathstring Yes Node path resourcePropertystring Yes Resource property on node, e.g. shape, mesh, material_override subPropertystring Yes Property on the resource, e.g. size, radius, albedo_color valuestring | number | boolean Yes Value in engine string format
Example: summer_set_resource_property(nodePath="./Player/CollisionShape3D", resourceProperty="shape", subProperty="size", value="Vector3(1, 2, 1)")summer_remove_node Remove a node from the scene tree. All children are removed. Cannot remove root. Supports undo.
Parameter Type Required Description pathstring Yes Node path to remove
summer_save_scene Save the current scene to disk. Call after making changes to persist them.
Parameter Type Required Description pathstring No Save-as path for creating a new scene file, e.g. res://levels/level2.tscn
summer_open_scene Open a scene file in the editor. Use to switch between scenes.
Parameter Type Required Description pathstring Yes Scene path, e.g. res://main.tscn
summer_instantiate_scene Add an existing scene or 3D model as a child node. Use for .tscn prefabs or .glb/.gltf models.
Parameter Type Required Description parentstring Yes Parent node path scenestring Yes Scene/model path, e.g. res://player.tscn or res://models/tree.glb namestring No Override the instance name
summer_connect_signal Connect a signal between two nodes. The receiver must have a script with the specified method.
Parameter Type Required Description emitterstring Yes Node that fires the signal signalstring Yes Signal name, e.g. body_entered, pressed, timeout receiverstring Yes Node with the handler script methodstring Yes Method name in receiver’s script
Common signals: body_entered, body_exited, pressed, timeout, area_entered, input_event.summer_select_node Select a node in the editor’s scene tree and show it in the inspector.
Parameter Type Required Description nodePathstring Yes Node path to select scenePathstring No Open this scene first, then select the node
summer_replace_node Replace a node with a different type or scene, preserving position and children.
Parameter Type Required Description pathstring Yes Node path to replace typestring No New node type, e.g. RigidBody3D scenestring No Scene to replace with, e.g. res://enemies/boss.tscn
summer_get_diagnostics Quick overview of errors and warnings from the editor console and runtime debugger. Call this first before diving into console or debugger details.
Workflow: summer_get_diagnostics → if errors, use summer_get_console or summer_get_debugger_errors → fix → summer_get_diagnostics again to verify.summer_get_console Read recent messages from the editor’s Output panel. Use after diagnostics indicate console issues.
Parameter Type Required Description max_linesnumber No Max lines to return (default 100) filterstring No Only return lines containing this string typeenum No Filter by: error, warning, std, editor
summer_clear_console Clear the editor’s Output panel. Useful before running the game for a clean slate.
summer_get_debugger_errors Read runtime errors and warnings from the debugger (null refs, missing nodes, physics errors). Different from console. These occur while the game is running.
Parameter Type Required Description max_errorsnumber No Max errors to return (default 50) include_stackboolean No Include stack traces
summer_play Start running the game in the engine. Use summer_game_snapshot to see what the player sees.
Parameter Type Required Description scenestring No Scene to run instead of main scene
summer_stop Stop the running game. Call before making scene changes. Some operations require the game to be stopped.
summer_is_running Check if the game is currently running. Returns the active scene path if running.
summer_viewport_snapshot Capture a screenshot of the editor’s 3D/2D viewport (editor camera, not game camera).
summer_game_snapshot Capture a screenshot of the running game (player’s view). Call summer_play first. Returns base64 JPEG.
summer_project_setting Set a project setting in project.godot.
Parameter Type Required Description keystring Yes Setting key path, e.g. application/config/name valuestring | number | boolean Yes Setting value
Common settings: application/config/name, application/run/main_scene, display/window/size/viewport_width, physics/3d/default_gravity.Set up input controls. Creates the action if it doesn’t exist, then binds events.
Parameter Type Required Description namestring Yes Action name, e.g. jump, move_forward eventsarray Yes Array of input event objects
Event format: { type: "key", key: "W" } or { type: "mouse_button", button: 1 } (1=left, 2=right, 3=middle).summer_get_scene_tree Get the full scene tree structure of the currently open scene. Returns all nodes with types, paths, and children. Use to understand the scene before making changes.
summer_import_from_url Download a file from a URL and import it into the project. Triggers the engine’s full import pipeline. Use for .glb, .gltf, .obj, .png, .ogg, etc.
Parameter Type Required Description urlstring Yes HTTP(S) URL to download from pathstring No Target path in project. Auto-inferred from URL if omitted.
summer_import_from_url_batch Download multiple files from URLs in one operation. Single filesystem scan after all downloads. Faster than importing one at a time.
Parameter Type Required Description importsarray Yes Array of {url, path} objects
Next Steps
Building a Game Step-by-step: how an AI builds a full game with these tools
MCP Setup Connect Cursor, Claude Code, or Windsurf
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