SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

checkpoint-system

claude-code claude-opus-4-8 ✓ resolved GOOD_SUCCESS ↑ View task
Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.
Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.
Classification , post-hoc; cannot change the reward
GOOD_SUCCESSLegitimate solve, implements the asked-for behavior; tests verify real functionality.
SubtypeLegitimate Solution
EvidenceTest output shows 'VALIDATION_PASSED: Checkpoint beacon works correctly' with reward 1.0. Agent wrote checkpoint.gd implementing Checkpoint class with all required signals (activated, level_complete), exports (checkpoint_id, is_final_checkpoint, charge_gradient, scale_curve, beacon, charge_label), and methods (apply_charge, _on_body_entered, reset). Agent created checkpoint.tscn with Area2D root, CollisionShape2D (32x32), Beacon Sprite2D, ChargeLabel Label, authored Gradient and Curve sub-resources with correct color stops (0.1,0.2,0.6 → 0.2,0.9,1.0 → 1,1,1) and baked curve samples (1.0→1.8→2.0), and wired node references. Agent debugged Godot scene serialization semantics to discover the required node_paths=PackedStringArray marker for export resolution."
Root causeAgent successfully implemented all task requirements through proper understanding of the Godot scene/script system. The agent discovered and corrected a non-obvious serialization detail (node_paths marker in .tscn) through systematic debugging, demonstrating genuine problem-solving rather than pattern matching.
RecommendationN/A - task is fine
Trajectory
Tool-by-tool agent trajectory
41 tool calls · 3 tool types · 41 steps
Build an animated checkpoint beacon for a 2D platformer. Create `scenes/checkpoint.tscn` with an `Area2D` root node named `Checkpoint` (attach `scripts/checkpoint.gd`). Give it these children: - a `CollisionShape2D` using a `RectangleShape2D` sized 32×32, - a `Sprite2D` named `Beacon` (the visual that pulses as the checkpoint charges), - a `Label` named `ChargeLabel`. Wire the area so bodies entering it reach the script's `_on_body_entered(body)` handler. In `scripts/checkpoint.gd`, implement the `Checkpoint` class: - Export an int `checkpoint_id` (default `0`) and a bool `is_final_checkpoint` (default `false`). Expose a public bool `is_active` (default `false`). - Export a `Gradient` resource named `charge_gradient`, authored in the scene with three color stops: offset `0.0` is deep blue `Color(0.1, 0.2, 0.6)`, offset `0.5` is bright cyan `Color(0.2, 0.9, 1.0)`, offset `1.0` is white `Color(1.0, 1.0, 1.0)`. - Export a `Curve` resource named `scale_curve`, authored so that sampling its baked value returns `1.0` at position `0.0`, `1.8` at position `0.5`, and `2.0` at position `1.0`. - Export a `Sprite2D` reference named `beacon` and a `Label` reference named `charge_label`, each wired in the scene to the `Beacon` and `ChargeLabel` nodes. Behavior: - `apply_charge(t: float)` drives the beacon's look for a charge fraction `t` in `[0, 1]`: set `beacon.modulate` to `charge_gradient` sampled at `t`, and set `beacon.scale` to `Vector2.ONE * scale_curve.sample_baked(t)`. - Only the player can light a checkpoint , the player belongs to the `"Player"` group; any other body that enters must be ignored. The first time the player reaches an unlit checkpoint, set it active, drive the beacon to full charge by calling `apply_charge(1.0)`, write the checkpoint's id into `charge_label.text`, and emit `activated` carrying `checkpoint_id`. While it stays lit, re-touching it does nothing. - A final checkpoint (`is_final_checkpoint == true`) must also emit `level_complete` at the moment it activates. - `reset()` re-arms the checkpoint (sets `is_active` back to false) so it can be lit again. Declare the signals `activated(id: int)` and `level_complete`.
I'll create both files. This is a straightforward Godot scene + script task.
Write
{
  "file_path": "/home/user/task/scripts/checkpoint.gd",
  "content": "class_name Checkpoint\nextends Area2D\n\n## Emitted when the player first lights this checkpoint.\nsignal activated(id: int)\n## Emitted when a final checkpoint activates, completing the level.\nsignal level_complete\n\n## Identifies this checkpoint within the level.\n@export var checkpoint_id: int = 0\n## When true, lighting this checkpoint also finishes the level.\n@export var is_final_checkpoint: bool = false\n\n## True once the player has lit this checkpoint.\nvar is_active: bool = false\n\n## Colors the beacon takes as it charges from cold (0.0) to full (1.0).\n@export var charge_gradient: Gradient\n## Drives the beacon's scale as it charges from 0.0 to 1.0.\n@export var scale_curve: Curve\n\n## The pulsing beacon visual.\n@export var beacon: Sprite2D\n## Displays the checkpoint id once lit.\n@export var charge_label: Label\n\n\n## Drives the beacon's look for a charge fraction [param t] in [0, 1].\nfunc apply_charge(t: float) -> void:\n\tbeacon.modulate = charge_gradient.sample(t)\n\tbeacon.scale = Vector2.ONE * scale_curve.sample_baked(t)\n\n\nfunc _on_body_entered(body: Node2D) -> void:\n\t# Only the player can light a checkpoint, and only an unlit one.\n\tif not body.is_in_group(\"Player\"):\n\t\treturn\n\tif is_active:\n\t\treturn\n\n\tis_active = true\n\tapply_charge(1.0)\n\tcharge_label.text = str(checkpoint_id)\n\tactivated.emit(checkpoint_id)\n\n\tif is_final_checkpoint:\n\t\tlevel_complete.emit()\n\n\n## Re-arms the checkpoint so it can be lit again.\nfunc reset() -> void:\n\tis_active = false\n"
}
output
<tool_use_error>File has not been read yet. Read it first before writing to it.</tool_use_error>

[error] tool reported failure
Read
{
  "file_path": "/home/user/task/scripts/checkpoint.gd"
}
output
1	extends Area2D
2	class_name Checkpoint
3	
4	func _ready() -> void:
5		pass
6
Write
{
  "file_path": "/home/user/task/scripts/checkpoint.gd",
  "content": "class_name Checkpoint\nextends Area2D\n\n## Emitted when the player first lights this checkpoint.\nsignal activated(id: int)\n## Emitted when a final checkpoint activates, completing the level.\nsignal level_complete\n\n## Identifies this checkpoint within the level.\n@export var checkpoint_id: int = 0\n## When true, lighting this checkpoint also finishes the level.\n@export var is_final_checkpoint: bool = false\n\n## True once the player has lit this checkpoint.\nvar is_active: bool = false\n\n## Colors the beacon takes as it charges from cold (0.0) to full (1.0).\n@export var charge_gradient: Gradient\n## Drives the beacon's scale as it charges from 0.0 to 1.0.\n@export var scale_curve: Curve\n\n## The pulsing beacon visual.\n@export var beacon: Sprite2D\n## Displays the checkpoint id once lit.\n@export var charge_label: Label\n\n\n## Drives the beacon's look for a charge fraction [param t] in [0, 1].\nfunc apply_charge(t: float) -> void:\n\tbeacon.modulate = charge_gradient.sample(t)\n\tbeacon.scale = Vector2.ONE * scale_curve.sample_baked(t)\n\n\nfunc _on_body_entered(body: Node2D) -> void:\n\t# Only the player can light a checkpoint, and only an unlit one.\n\tif not body.is_in_group(\"Player\"):\n\t\treturn\n\tif is_active:\n\t\treturn\n\n\tis_active = true\n\tapply_charge(1.0)\n\tcharge_label.text = str(checkpoint_id)\n\tactivated.emit(checkpoint_id)\n\n\tif is_final_checkpoint:\n\t\tlevel_complete.emit()\n\n\n## Re-arms the checkpoint so it can be lit again.\nfunc reset() -> void:\n\tis_active = false\n"
}
output
The file /home/user/task/scripts/checkpoint.gd has been updated successfully. (file state is current in your context , no need to Read it back)
Now let me check the existing scene file and project structure.
Bash
ls -la && echo "---SCENES---" && ls -la scenes/ 2>/dev/null && echo "---PROJECT---" && cat project.godot 2>/dev/null | head -40
output
total 12
drwxr-xr-x 5 user user  128 Jun 21 19:05 .
drwxr-x--- 3 user user  128 Jun 21 19:05 ..
drwxr-xr-x 4 user user 4096 Jun 21 19:05 .godot
-rw-r--r-- 1 user user  205 Jun 21 07:51 project.godot
drwxr-xr-x 2 user user  128 Jun 21 07:51 scenes
drwxr-xr-x 2 user user 4096 Jun 21 19:06 scripts
---SCENES---
total 9
drwxr-xr-x 2 user user 128 Jun 21 07:51 .
drwxr-xr-x 5 user user 128 Jun 21 19:05 ..
-rw-r--r-- 1 user user  73 Jun 21 07:51 checkpoint.tscn
-rw-r--r-- 1 user user 208 Jun 21 07:51 main.tscn
-rw-r--r-- 1 user user 291 Jun 21 07:51 test.tscn
---PROJECT---
config_version=5

[application]

config/name="Checkpoint System"
run/main_scene="res://scenes/main.tscn"
config/features=PackedStringArray("4.4")

[rendering]

renderer/rendering_method="gl_compatibility"

[stdout]
total 12
drwxr-xr-x 5 user user  128 Jun 21 19:05 .
drwxr-x--- 3 user user  128 Jun 21 19:05 ..
drwxr-xr-x 4 user user 4096 Jun 21 19:05 .godot
-rw-r--r-- 1 user user  205 Jun 21 07:51 project.godot
drwxr-xr-x 2 user user  128 Jun 21 07:51 scenes
drwxr-xr-x 2 user user 4096 Jun 21 19:06 scripts
---SCENES---
total 9
drwxr-xr-x 2 user user 128 Jun 21 07:51 .
drwxr-xr-x 5 user user 128 Jun 21 19:05 ..
-rw-r--r-- 1 user user  73 Jun 21 07:51 checkpoint.tscn
-rw-r--r-- 1 user user 208 Jun 21 07:51 main.tscn
-rw-r--r-- 1 user user 291 Jun 21 07:51 test.tscn
---PROJECT---
config_version=5

[application]

config/name="Checkpoint System"
run/main_scene="res://scenes/main.tscn"
config/features=PackedStringArray("4.4")

[rendering]

renderer/rendering_method="gl_compatibility"
Bash
echo "===checkpoint.tscn===" && cat scenes/checkpoint.tscn && echo "===main.tscn===" && cat scenes/main.tscn && echo "===test.tscn===" && cat scenes/test.tscn && echo "===uid file===" && cat scripts/checkpoint.gd.uid 2>/dev/null; ls scripts/
output
===checkpoint.tscn===
[gd_scene load_steps=1 format=3]

[node name="Checkpoint" type="Area2D"]
===main.tscn===
[gd_scene load_steps=2 format=3]

[ext_resource type="PackedScene" path="res://scenes/checkpoint.tscn" id="1"]

[node name="Main" type="Node2D"]

[node name="Checkpoint" parent="." instance=ExtResource("1")]
===test.tscn===
[gd_scene load_steps=3 format=3]

[ext_resource type="Script" path="res://scripts/test.gd" id="1"]
[ext_resource type="PackedScene" path="res://scenes/main.tscn" id="2"]

[node name="TestRunner" type="Node"]
script = ExtResource("1")

[node name="Main" parent="." instance=ExtResource("2")]
===uid file===
uid://bh5v66gv2lgfa
checkpoint.gd
checkpoint.gd.uid
test.gd
test.gd.uid

[stdout]
===checkpoint.tscn===
[gd_scene load_steps=1 format=3]

[node name="Checkpoint" type="Area2D"]
===main.tscn===
[gd_scene load_steps=2 format=3]

[ext_resource type="PackedScene" path="res://scenes/checkpoint.tscn" id="1"]

[node name="Main" type="Node2D"]

[node name="Checkpoint" parent="." instance=ExtResource("1")]
===test.tscn===
[gd_scene load_steps=3 format=3]

[ext_resource type="Script" path="res://scripts/test.gd" id="1"]
[ext_resource type="PackedScene" path="res://scenes/main.tscn" id="2"]

[node name="TestRunner" type="Node"]
script = ExtResource("1")

[node name="Main" parent="." instance=ExtResource("2")]
===uid file===
uid://bh5v66gv2lgfa
checkpoint.gd
checkpoint.gd.uid
test.gd
test.gd.uid
Now I'll write the scene file, following the project's path-based ext_resource convention.
Write
{
  "file_path": "/home/user/task/scenes/checkpoint.tscn",
  "content": "[gd_scene load_steps=5 format=3]\n\n[ext_resource type=\"Script\" path=\"res://scripts/checkpoint.gd\" id=\"1\"]\n\n[sub_resource type=\"Gradient\" id=\"Gradient_1\"]\noffsets = PackedFloat32Array(0, 0.5, 1)\ncolors = PackedColorArray(0.1, 0.2, 0.6, 1, 0.2, 0.9, 1, 1, 1, 1, 1, 1)\n\n[sub_resource type=\"Curve\" id=\"Curve_1\"]\nmax_value = 2.0\n_data = [Vector2(0, 1), 0.0, 0.0, 0, 0, Vector2(0.5, 1.8), 0.0, 0.0, 0, 0, Vector2(1, 2), 0.0, 0.0, 0, 0]\npoint_count = 3\n\n[sub_resource type=\"RectangleShape2D\" id=\"Rect_1\"]\nsize = Vector2(32, 32)\n\n[node name=\"Checkpoint\" type=\"Area2D\"]\nscript = ExtResource(\"1\")\ncharge_gradient = SubResource(\"Gradient_1\")\nscale_curve = SubResource(\"Curve_1\")\nbeacon = NodePath(\"Beacon\")\ncharge_label = NodePath(\"ChargeLabel\")\n\n[node name=\"CollisionShape2D\" type=\"CollisionShape2D\" parent=\".\"]\nshape = SubResource(\"Rect_1\")\n\n[node name=\"Beacon\" type=\"Sprite2D\" parent=\".\"]\n\n[node name=\"ChargeLabel\" type=\"Label\" parent=\".\"]\n\n[connection signal=\"body_entered\" from=\".\" to=\".\" method=\"_on_body_entered\"]\n"
}
output
<tool_use_error>File has not been read yet. Read it first before writing to it.</tool_use_error>

[error] tool reported failure
Read
{
  "file_path": "/home/user/task/scenes/checkpoint.tscn"
}
output
1	[gd_scene load_steps=1 format=3]
2	
3	[node name="Checkpoint" type="Area2D"]
4
Write
{
  "file_path": "/home/user/task/scenes/checkpoint.tscn",
  "content": "[gd_scene load_steps=5 format=3]\n\n[ext_resource type=\"Script\" path=\"res://scripts/checkpoint.gd\" id=\"1\"]\n\n[sub_resource type=\"Gradient\" id=\"Gradient_1\"]\noffsets = PackedFloat32Array(0, 0.5, 1)\ncolors = PackedColorArray(0.1, 0.2, 0.6, 1, 0.2, 0.9, 1, 1, 1, 1, 1, 1)\n\n[sub_resource type=\"Curve\" id=\"Curve_1\"]\nmax_value = 2.0\n_data = [Vector2(0, 1), 0.0, 0.0, 0, 0, Vector2(0.5, 1.8), 0.0, 0.0, 0, 0, Vector2(1, 2), 0.0, 0.0, 0, 0]\npoint_count = 3\n\n[sub_resource type=\"RectangleShape2D\" id=\"Rect_1\"]\nsize = Vector2(32, 32)\n\n[node name=\"Checkpoint\" type=\"Area2D\"]\nscript = ExtResource(\"1\")\ncharge_gradient = SubResource(\"Gradient_1\")\nscale_curve = SubResource(\"Curve_1\")\nbeacon = NodePath(\"Beacon\")\ncharge_label = NodePath(\"ChargeLabel\")\n\n[node name=\"CollisionShape2D\" type=\"CollisionShape2D\" parent=\".\"]\nshape = SubResource(\"Rect_1\")\n\n[node name=\"Beacon\" type=\"Sprite2D\" parent=\".\"]\n\n[node name=\"ChargeLabel\" type=\"Label\" parent=\".\"]\n\n[connection signal=\"body_entered\" from=\".\" to=\".\" method=\"_on_body_entered\"]\n"
}
output
The file /home/user/task/scenes/checkpoint.tscn has been updated successfully. (file state is current in your context , no need to Read it back)
Let me check the test setup and validate by running Godot if available.
Bash
cat scripts/test.gd 2>/dev/null; echo "---"; which godot godot4 2>/dev/null || echo "no godot binary"
output
extends Node

const GTOL := 0.04
const CTOL := 0.09

func _ready() -> void:
	await get_tree().process_frame
	run_validation()

func run_validation() -> void:
	var node = get_node_or_null("Main")
	if node == null:
		return _fail("Main scene not found")
	var cp = node.get_node_or_null("Checkpoint")
	if cp == null:
		return _fail("Checkpoint node not found under Main")
	if not (cp is Area2D):
		return _fail("Checkpoint must extend Area2D")

	var col = cp.get_node_or_null("CollisionShape2D")
	if col == null or not (col.shape is RectangleShape2D):
		return _fail("Checkpoint needs a CollisionShape2D with a RectangleShape2D")
	var rect := col.shape as RectangleShape2D
	if not is_equal_approx(rect.size.x, 32.0) or not is_equal_approx(rect.size.y, 32.0):
		return _fail("RectangleShape2D size must be 32x32")

	var beacon_node = cp.get_node_or_null("Beacon")
	if beacon_node == null or not (beacon_node is Sprite2D):
		return _fail("Checkpoint must have a Sprite2D child named Beacon")
	var label_node = cp.get_node_or_null("ChargeLabel")
	if label_node == null or not (label_node is Label):
		return _fail("Checkpoint must have a Label child named ChargeLabel")

	if not cp.has_signal("activated"):
		return _fail("Checkpoint must declare 'activated' signal")
	if not cp.has_signal("level_complete"):
		return _fail("Checkpoint must declare 'level_complete' signal")

	# exported resources
	var grad = cp.get("charge_gradient")
	if grad == null or not (grad is Gradient):
		return _fail("charge_gradient must be an exported Gradient resource authored in the scene")
	var curve = cp.get("scale_curve")
	if curve == null or not (curve is Curve):
		return _fail("scale_curve must be an exported Curve resource authored in the scene")

	# exported node references must be wired in the scene
	var beacon_ref = cp.get("beacon")
	if beacon_ref == null or not (beacon_ref is Sprite2D):
		return _fail("beacon export must be wired to the Beacon Sprite2D in the scene")
	if beacon_ref != beacon_node:
		return _fail("beacon export must point to the Beacon node")
	var label_ref = cp.get("charge_label")
	if label_ref == null or not (label_ref is Label):
		return _fail("charge_label export must be wired to the ChargeLabel in the scene")
	if label_ref != label_node:
		return _fail("charge_label export must point to the ChargeLabel node")

	# gradient color stops
	if not _color_near(grad.sample(0.0), Color(0.1, 0.2, 0.6)):
		return _fail("charge_gradient at offset 0.0 must be deep blue Color(0.1,0.2,0.6)")
	if not _color_near(grad.sample(0.5), Color(0.2, 0.9, 1.0)):
		return _fail("charge_gradient at offset 0.5 must be bright cyan Color(0.2,0.9,1.0) , needs a middle color stop")
	if not _color_near(grad.sample(1.0), Color(1.0, 1.0, 1.0)):
		return _fail("charge_gradient at offset 1.0 must be white Color(1,1,1)")

	# curve baked samples
	if absf(curve.sample_baked(0.0) - 1.0) > CTOL:
		return _fail("scale_curve at position 0.0 must bake to 1.0")
	if absf(curve.sample_baked(0.5) - 1.8) > CTOL:
		return _fail("scale_curve at position 0.5 must bake to 1.8 , needs a middle control point")
	if absf(curve.sample_baked(1.0) - 2.0) > CTOL:
		return _fail("scale_curve at position 1.0 must bake to 2.0")

	# behavioral: apply_charge drives the wired beacon
	if not cp.has_method("apply_charge"):
		return _fail("Checkpoint must define apply_charge(t)")
	cp.apply_charge(0.5)
	if not _color_near(beacon_ref.modulate, Color(0.2, 0.9, 1.0)):
		return _fail("apply_charge(0.5) must set beacon.modulate to the gradient color at 0.5 (cyan)")
	if absf(beacon_ref.scale.x - 1.8) > CTOL or absf(beacon_ref.scale.y - 1.8) > CTOL:
		return _fail("apply_charge(0.5) must set beacon.scale to Vector2.ONE * scale_curve.sample_baked(0.5) (~1.8)")
	cp.apply_charge(1.0)
	if not _color_near(beacon_ref.modulate, Color(1.0, 1.0, 1.0)):
		return _fail("apply_charge(1.0) must set beacon.modulate to white")
	if absf(beacon_ref.scale.x - 2.0) > CTOL or absf(beacon_ref.scale.y - 2.0) > CTOL:
		return _fail("apply_charge(…[truncated]
My implementation matches all test requirements. Let me run the validation.
Bash
godot --headless --path . scenes/test.tscn 2>&1 | grep -E "VALIDATION|ERROR|SCRIPT ERROR" | head -20
output
VALIDATION_FAILED: beacon export must be wired to the Beacon Sprite2D in the scene

[stdout]
VALIDATION_FAILED: beacon export must be wired to the Beacon Sprite2D in the scene
Bash
godot --headless --path . scenes/test.tscn 2>&1 | grep -iE "error|warning|beacon|nodepath" | head -20
output
WARNING: Started the engine as `root`/superuser. This is a security risk, and subsystems like audio may not work correctly.
Set the environment variable `GODOT_SILENCE_ROOT_WARNING` to 1 to silence this warning.
VALIDATION_FAILED: beacon export must be wired to the Beacon Sprite2D in the scene

[stdout]
WARNING: Started the engine as `root`/superuser. This is a security risk, and subsystems like audio may not work correctly.
Set the environment variable `GODOT_SILENCE_ROOT_WARNING` to 1 to silence this warning.
VALIDATION_FAILED: beacon export must be wired to the Beacon Sprite2D in the scene
Bash
cat > /tmp/dbg.gd <<'EOF'
extends SceneTree
func _init():
	var ps = load("res://scenes/checkpoint.tscn")
	var cp = ps.instantiate()
	get_root().add_child(cp)
	print("beacon=", cp.get("beacon"), " type=", typeof(cp.get("beacon")))
	print("charge_label=", cp.get("charge_label"))
	quit()
EOF
godot --headless --path . --script /tmp/dbg.gd 2>&1 | grep -vE "root.superuser|GODOT_SILENCE|security risk" | head
output
Godot Engine v4.4.stable.official.4c311cbee - https://godotengine.org
     at: setup2 (main/main.cpp:3181)

beacon=<null> type=0
charge_label=<null>

[stdout]
Godot Engine v4.4.stable.official.4c311cbee - https://godotengine.org
     at: setup2 (main/main.cpp:3181)

beacon=<null> type=0
charge_label=<null>
Bash
godot --headless --path . --script /tmp/dbg.gd 2>&1 | grep -vE "root.superuser|GODOT_SILENCE|security risk|setup2|Godot Engine|main/main" | head -20
output
beacon=<null> type=0
charge_label=<null>

[stdout]
beacon=<null> type=0
charge_label=<null>
Let me see how Godot itself serializes a node export, by building and saving the scene programmatically.
Bash
cat > /tmp/gen.gd <<'EOF'
extends SceneTree
func _init():
	var root = Area2D.new()
	root.name = "Checkpoint"
	root.set_script(load("res://scripts/checkpoint.gd"))
	var beacon = Sprite2D.new(); beacon.name = "Beacon"
	var label = Label.new(); label.name = "ChargeLabel"
	root.add_child(beacon); beacon.owner = root
	root.add_child(label); label.owner = root
	root.set("beacon", beacon)
	root.set("charge_label", label)
	var ps = PackedScene.new()
	ps.pack(root)
	ResourceSaver.save(ps, "res://scenes/_gen.tscn")
	quit()
EOF
godot --headless --path . --script /tmp/gen.gd 2>&1 | grep -vE "root.superuser|GODOT_SILENCE|security|setup2|Godot Engine|main/main"
echo "=== generated ==="
cat scenes/_gen.tscn
output
ERROR: 1 RID allocations of type 'P11GodotArea2D' were leaked at exit.
WARNING: 3 RIDs of type "CanvasItem" were leaked.
     at: _free_rids (servers/rendering/renderer_canvas_cull.cpp:2679)
WARNING: ObjectDB instances leaked at exit (run with --verbose for details).
     at: cleanup (core/object/object.cpp:2378)
ERROR: 1 resources still in use at exit (run with --verbose for details).
   at: clear (core/io/resource.cpp:614)
=== generated ===
[gd_scene load_steps=2 format=3]

[ext_resource type="Script" path="res://scripts/checkpoint.gd" id="1_qmfp6"]

[node name="Checkpoint" type="Area2D" node_paths=PackedStringArray("beacon", "charge_label")]
script = ExtResource("1_qmfp6")
beacon = NodePath("Beacon")
charge_label = NodePath("ChargeLabel")

[node name="Beacon" type="Sprite2D" parent="."]

[node name="ChargeLabel" type="Label" parent="."]

[stdout]
ERROR: 1 RID allocations of type 'P11GodotArea2D' were leaked at exit.
WARNING: 3 RIDs of type "CanvasItem" were leaked.
     at: _free_rids (servers/rendering/renderer_canvas_cull.cpp:2679)
WARNING: ObjectDB instances leaked at exit (run with --verbose for details).
     at: cleanup (core/object/object.cpp:2378)
ERROR: 1 resources still in use at exit (run with --verbose for details).
   at: clear (core/io/resource.cpp:614)
=== generated ===
[gd_scene load_steps=2 format=3]

[ext_resource type="Script" path="res://scripts/checkpoint.gd" id="1_qmfp6"]

[node name="Checkpoint" type="Area2D" node_paths=PackedStringArray("beacon", "charge_label")]
script = ExtResource("1_qmfp6")
beacon = NodePath("Beacon")
charge_label = NodePath("ChargeLabel")

[node name="Beacon" type="Sprite2D" parent="."]

[node name="ChargeLabel" type="Label" parent="."]
Found it , the node line needs a `node_paths=PackedStringArray(...)` marker for the export references to resolve. Let me fix my scene and clean up the temp file.
Edit
{
  "replace_all": false,
  "file_path": "/home/user/task/scenes/checkpoint.tscn",
  "old_string": "[node name=\"Checkpoint\" type=\"Area2D\"]\nscript = ExtResource(\"1\")",
  "new_string": "[node name=\"Checkpoint\" type=\"Area2D\" node_paths=PackedStringArray(\"beacon\", \"charge_label\")]\nscript = ExtResource(\"1\")"
}
output
The file /home/user/task/scenes/checkpoint.tscn has been updated successfully. (file state is current in your context , no need to Read it back)
Bash
rm -f scenes/_gen.tscn scenes/_gen.tscn.uid /tmp/gen.gd /tmp/dbg.gd
godot --headless --path . scenes/test.tscn 2>&1 | grep -E "VALIDATION" | head
output
VALIDATION_PASSED: Checkpoint beacon works correctly

[stdout]
VALIDATION_PASSED: Checkpoint beacon works correctly
Validation passes. Both files are complete and working. ## Summary **`scripts/checkpoint.gd`** , the `Checkpoint` class (`extends Area2D`): - Signals `activated(id: int)` and `level_complete`. - Exports `checkpoint_id` (0), `is_final_checkpoint` (false), plus public `is_active` (false). - Exported `charge_gradient: Gradient`, `scale_curve: Curve`, and node refs `beacon: Sprite2D` / `charge_label: Label`. - `apply_charge(t)` sets `beacon.modulate` from the gradient and `beacon.scale` from the baked curve. - `_on_body_entered` ignores non-`"Player"` bodies and already-lit checkpoints; on first player touch it activates, charges to full, writes the id into the label, emits `activated`, and emits `level_complete` if final. - `reset()` re-arms it. **`scenes/checkpoint.tscn`** , `Checkpoint` (Area2D) with the script, a `CollisionShape2D` (32×32 `RectangleShape2D`), a `Beacon` Sprite2D, and a `ChargeLabel` Label. The authored `Gradient` (blue→cyan→white at 0/0.5/1) and `Curve` (1.0/1.8/2.0, `max_value = 2.0` so 2.0 isn't clamped) are wired in, `body_entered` is connected to `_on_body_entered`, and the node refs resolve via the `node_paths=PackedStringArray("beacon", "charge_label")` marker. One non-obvious detail worth noting: hand-written `.tscn` node-export references only resolve if the node line carries that `node_paths=PackedStringArray(...)` marker , without it the exports load as `null`.
Final diff , what the agent changed

No file changes, the agent left the workspace untouched.

Verifier output , the proof behind the reward
tests/test.sh
Godot Engine v4.4.stable.official.4c311cbee - https://godotengine.org
WARNING: Started the engine as `root`/superuser. This is a security risk, and subsystems like audio may not work correctly.
Set the environment variable `GODOT_SILENCE_ROOT_WARNING` to 1 to silence this warning.
     at: setup2 (main/main.cpp:3181)

VALIDATION_PASSED: Checkpoint beacon works correctly

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_33b0d66f404b4195. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_33b0d66f404b4195 · verifier authoritative; classifier explanatory.