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: `VALIDATION_PASSED: Checkpoint beacon works correctly` (verifier/test-stdout.txt, line 6). Reward 1.0 confirmed in result.json. Agent's implementation includes: (1) checkpoint.gd script with correct exports (`checkpoint_id`, `is_final_checkpoint`, `charge_gradient`, `scale_curve`, `beacon`, `charge_label`), public `is_active` property, and all required methods (`apply_charge`, `_on_body_entered`, `reset`); (2) signals `activated(id: int)` and `level_complete` declared; (3) scenes/checkpoint.tscn with Area2D root, CollisionShape2D (32×32), Sprite2D (Beacon), Label (ChargeLabel), Gradient resource with colors at offsets 0.0 (0.1,0.2,0.6), 0.5 (0.2,0.9,1.0), 1.0 (1,1,1), Curve resource with points at 0.0→1.0, 0.5→1.8, 1.0→2.0, node_paths declaration for export references, and body_entered signal connection to _on_body_entered. All test checks pass in test.gd lines 14-113 (node structure, shape size, gradient colors, curve samples, apply_charge behavior, body group filtering, signal emission).
Root causeThe agent correctly understood the detailed specification, implemented all required components accurately, and resolved a Godot-specific scene format issue (node_paths declaration) through systematic debugging. The implementation is complete, functional, and passes all validation checks.
RecommendationN/A - task is fine
Trajectory
Tool-by-tool agent trajectory
42 tool calls · 3 tool types · 42 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 the script and scene files for the checkpoint beacon. Let me write both.
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.\nsignal level_complete\n\n@export var checkpoint_id: int = 0\n@export var is_final_checkpoint: bool = false\n\n## Drives the beacon's colour as it charges from deep blue to white.\n@export var charge_gradient: Gradient\n## Drives the beacon's scale as it charges.\n@export var scale_curve: Curve\n\n## Scene references.\n@export var beacon: Sprite2D\n@export var charge_label: Label\n\n## Whether this checkpoint is currently lit.\nvar is_active: bool = false\n\n\n## Drives the beacon's look for a charge fraction `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.\n\tif not body.is_in_group(\"Player\"):\n\t\treturn\n\t# While it stays lit, re-touching it does nothing.\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
Bash
ls -la /home/user/task /home/user/task/scenes /home/user/task/scripts 2>/dev/null
output
/home/user/task:
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 19:05 scripts

/home/user/task/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

/home/user/task/scripts:
total 14
drwxr-xr-x 2 user user 4096 Jun 21 19:05 .
drwxr-xr-x 5 user user  128 Jun 21 19:05 ..
-rw-r--r-- 1 user user   67 Jun 21 19:01 checkpoint.gd
-rw-r--r-- 1 user user   20 Jun 21 19:05 checkpoint.gd.uid
-rw-r--r-- 1 user user 6642 Jun 21 19:01 test.gd
-rw-r--r-- 1 user user   20 Jun 21 19:05 test.gd.uid

[stdout]
/home/user/task:
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 19:05 scripts

/home/user/task/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

/home/user/task/scripts:
total 14
drwxr-xr-x 2 user user 4096 Jun 21 19:05 .
drwxr-xr-x 5 user user  128 Jun 21 19:05 ..
-rw-r--r-- 1 user user   67 Jun 21 19:01 checkpoint.gd
-rw-r--r-- 1 user user   20 Jun 21 19:05 checkpoint.gd.uid
-rw-r--r-- 1 user user 6642 Jun 21 19:01 test.gd
-rw-r--r-- 1 user user   20 Jun 21 19:05 test.gd.uid
Let me look at the existing files to match conventions and understand any tests.
Read
{
  "file_path": "/home/user/task/scripts/test.gd"
}
output
1	extends Node
2	
3	const GTOL := 0.04
4	const CTOL := 0.09
5	
6	func _ready() -> void:
7		await get_tree().process_frame
8		run_validation()
9	
10	func run_validation() -> void:
11		var node = get_node_or_null("Main")
12		if node == null:
13			return _fail("Main scene not found")
14		var cp = node.get_node_or_null("Checkpoint")
15		if cp == null:
16			return _fail("Checkpoint node not found under Main")
17		if not (cp is Area2D):
18			return _fail("Checkpoint must extend Area2D")
19	
20		var col = cp.get_node_or_null("CollisionShape2D")
21		if col == null or not (col.shape is RectangleShape2D):
22			return _fail("Checkpoint needs a CollisionShape2D with a RectangleShape2D")
23		var rect := col.shape as RectangleShape2D
24		if not is_equal_approx(rect.size.x, 32.0) or not is_equal_approx(rect.size.y, 32.0):
25			return _fail("RectangleShape2D size must be 32x32")
26	
27		var beacon_node = cp.get_node_or_null("Beacon")
28		if beacon_node == null or not (beacon_node is Sprite2D):
29			return _fail("Checkpoint must have a Sprite2D child named Beacon")
30		var label_node = cp.get_node_or_null("ChargeLabel")
31		if label_node == null or not (label_node is Label):
32			return _fail("Checkpoint must have a Label child named ChargeLabel")
33	
34		if not cp.has_signal("activated"):
35			return _fail("Checkpoint must declare 'activated' signal")
36		if not cp.has_signal("level_complete"):
37			return _fail("Checkpoint must declare 'level_complete' signal")
38	
39		# exported resources
40		var grad = cp.get("charge_gradient")
41		if grad == null or not (grad is Gradient):
42			return _fail("charge_gradient must be an exported Gradient resource authored in the scene")
43		var curve = cp.get("scale_curve")
44		if curve == null or not (curve is Curve):
45			return _fail("scale_curve must be an exported Curve resource authored in the scene")
46	
47		# exported node references must be wired in the scene
48		var beacon_ref = cp.get("beacon")
49		if beacon_ref == null or not (beacon_ref is Sprite2D):
50			return _fail("beacon export must be wired to the Beacon Sprite2D in the scene")
51		if beacon_ref != beacon_node:
52			return _fail("beacon export must point to the Beacon node")
53		var label_ref = cp.get("charge_label")
54		if label_ref == null or not (label_ref is Label):
55			return _fail("charge_label export must be wired to the ChargeLabel in the scene")
56		if label_ref != label_node:
57			return _fail("charge_label export must point to the ChargeLabel node")
58	
59		# gradient color stops
60		if not _color_near(grad.sample(0.0), Color(0.1, 0.2, 0.6)):
61			return _fail("charge_gradient at offset 0.0 must be deep blue Color(0.1,0.2,0.6)")
62		if not _color_near(grad.sample(0.5), Color(0.2, 0.9, 1.0)):
63			return _fail("charge_gradient at offset 0.5 must be bright cyan Color(0.2,0.9,1.0) , needs a middle color stop")
64		if not _color_near(grad.sample(1.0), Color(1.0, 1.0, 1.0)):
65			return _fail("charge_gradient at offset 1.0 must be white Color(1,1,1)")
66	
67		# curve baked samples
68		if absf(curve.sample_baked(0.0) - 1.0) > CTOL:
69			return _fail("scale_curve at position 0.0 must bake to 1.0")
70		if absf(curve.sample_baked(0.5) - 1.8) > CTOL:
71			return _fail("scale_curve at position 0.5 must bake to 1.8 , needs a middle control point")
72		if absf(curve.sample_baked(1.0) - 2.0) > CTOL:
73			return _fail("scale_curve at position 1.0 must bake to 2.0")
74	
75		# behavioral: apply_charge drives the wired beacon
76		if not cp.has_method("apply_charge"):
77			return _fail("Checkpoint must define apply_charge(t)")
78		cp.apply_charge(0.5)
79		if not _color_near(beacon_ref.modulate, Color(0.2, 0.9, 1.0)):
80			return _fail("apply_charge(0.5) must set beacon.modulate to the gradient color at 0.5 (cyan)")
81		if absf(beacon_ref.scale.x - 1.8) > CTOL or absf(beacon_ref.scale.y - 1.8) > CTOL:
82			return _fail("apply_charge(0.5) must set beacon.scale to Vector2.ONE * scale_curve.sample_baked(0.5) (~1.8)")
83		cp.apply_charge(1.0)
84		if …[truncated]
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
Read
{
  "file_path": "/home/user/task/scenes/test.tscn"
}
output
1	[gd_scene load_steps=3 format=3]
2	
3	[ext_resource type="Script" path="res://scripts/test.gd" id="1"]
4	[ext_resource type="PackedScene" path="res://scenes/main.tscn" id="2"]
5	
6	[node name="TestRunner" type="Node"]
7	script = ExtResource("1")
8	
9	[node name="Main" parent="." instance=ExtResource("2")]
10
Read
{
  "file_path": "/home/user/task/scenes/main.tscn"
}
output
1	[gd_scene load_steps=2 format=3]
2	
3	[ext_resource type="PackedScene" path="res://scenes/checkpoint.tscn" id="1"]
4	
5	[node name="Main" type="Node2D"]
6	
7	[node name="Checkpoint" parent="." instance=ExtResource("1")]
8
Read
{
  "file_path": "/home/user/task/project.godot"
}
output
1	config_version=5
2	
3	[application]
4	
5	config/name="Checkpoint System"
6	run/main_scene="res://scenes/main.tscn"
7	config/features=PackedStringArray("4.4")
8	
9	[rendering]
10	
11	renderer/rendering_method="gl_compatibility"
12
Read
{
  "file_path": "/home/user/task/scripts/checkpoint.gd.uid"
}
output
1	uid://bh5v66gv2lgfa
2
Now I understand the full picture. The test instances `checkpoint.tscn` via `main.tscn`. Let me write the script and scene.
Write
{
  "file_path": "/home/user/task/scripts/checkpoint.gd",
  "content": "extends Area2D\nclass_name Checkpoint\n\n## Emitted when the player first lights this checkpoint.\nsignal activated(id: int)\n## Emitted when a final checkpoint activates.\nsignal level_complete\n\n@export var checkpoint_id: int = 0\n@export var is_final_checkpoint: bool = false\n\n## Drives the beacon's colour as it charges from deep blue to white.\n@export var charge_gradient: Gradient\n## Drives the beacon's scale as it charges.\n@export var scale_curve: Curve\n\n## Scene references.\n@export var beacon: Sprite2D\n@export var charge_label: Label\n\n## Whether this checkpoint is currently lit.\nvar is_active: bool = false\n\n\n## Drives the beacon's look for a charge fraction `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.\n\tif not body.is_in_group(\"Player\"):\n\t\treturn\n\t# While it stays lit, re-touching it does nothing.\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 the scene with the authored Gradient and Curve resources:
Write
{
  "file_path": "/home/user/task/scenes/checkpoint.tscn",
  "content": "[gd_scene load_steps=5 format=3 uid=\"uid://c8kqx2n0checkp\"]\n\n[ext_resource type=\"Script\" path=\"res://scripts/checkpoint.gd\" id=\"1_chkpt\"]\n\n[sub_resource type=\"RectangleShape2D\" id=\"RectangleShape2D_1\"]\nsize = Vector2(32, 32)\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[node name=\"Checkpoint\" type=\"Area2D\"]\nscript = ExtResource(\"1_chkpt\")\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(\"RectangleShape2D_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 run the validation to confirm everything works.
Bash
which godot godot4 2>/dev/null; ls ~/godot* 2>/dev/null; godot --version 2>/dev/null || godot4 --version 2>/dev/null || echo "no godot binary found"
output
/usr/local/bin/godot
4.4.stable.official.4c311cbee

[stdout]
/usr/local/bin/godot
4.4.stable.official.4c311cbee
Bash
godot --headless --path . res://scenes/test.tscn 2>&1 | grep -E "VALIDATION|SCRIPT ERROR|Parse Error|ERROR" | head -40
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
cat > /tmp/dbg.gd <<'EOF'
extends SceneTree
func _init():
	var ps = load("res://scenes/checkpoint.tscn")
	var cp = ps.instantiate()
	var root = Node.new()
	root.add_child(cp)
	print("beacon=", cp.get("beacon"), " type=", typeof(cp.get("beacon")))
	print("label=", cp.get("charge_label"))
	quit()
EOF
godot --headless --path . --script /tmp/dbg.gd 2>&1 | grep -iE "beacon|label|error" | head
output
beacon=<null> type=0
label=<null>
ERROR: 1 RID allocations of type 'P11GodotArea2D' were leaked at exit.
ERROR: 1 RID allocations of type 'P12GodotShape2D' were leaked at exit.
ERROR: 4 resources still in use at exit (run with --verbose for details).

[stdout]
beacon=<null> type=0
label=<null>
ERROR: 1 RID allocations of type 'P11GodotArea2D' were leaked at exit.
ERROR: 1 RID allocations of type 'P12GodotShape2D' were leaked at exit.
ERROR: 4 resources still in use at exit (run with --verbose for details).
Bash
cat > /tmp/gen.gd <<'EOF'
extends SceneTree
func _init():
	var cp = load("res://scripts/checkpoint.gd").new()
	cp.name = "Checkpoint"
	var be = Sprite2D.new(); be.name = "Beacon"
	var lb = Label.new(); lb.name = "ChargeLabel"
	var col = CollisionShape2D.new(); col.name = "CollisionShape2D"
	cp.add_child(be); cp.add_child(lb); cp.add_child(col)
	be.owner = cp; lb.owner = cp; col.owner = cp
	cp.beacon = be
	cp.charge_label = lb
	var ps = PackedScene.new()
	ps.pack(cp)
	ResourceSaver.save(ps, "res://scenes/_gen.tscn")
	quit()
EOF
godot --headless --path . --script /tmp/gen.gd 2>&1 | grep -iE "error" | head
echo "----"
cat /home/user/task/scenes/_gen.tscn
output
ERROR: 1 RID allocations of type 'P11GodotArea2D' were leaked at exit.
ERROR: 1 resources still in use at exit (run with --verbose for details).
----
[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="."]

[node name="CollisionShape2D" type="CollisionShape2D" parent="."]

[stdout]
ERROR: 1 RID allocations of type 'P11GodotArea2D' were leaked at exit.
ERROR: 1 resources still in use at exit (run with --verbose for details).
----
[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="."]

[node name="CollisionShape2D" type="CollisionShape2D" parent="."]
The root node needs the `node_paths=PackedStringArray(...)` declaration for export node references to resolve. Let me fix the scene.
Edit
{
  "replace_all": false,
  "file_path": "/home/user/task/scenes/checkpoint.tscn",
  "old_string": "[node name=\"Checkpoint\" type=\"Area2D\"]\nscript = ExtResource(\"1_chkpt\")",
  "new_string": "[node name=\"Checkpoint\" type=\"Area2D\" node_paths=PackedStringArray(\"beacon\", \"charge_label\")]\nscript = ExtResource(\"1_chkpt\")"
}
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 /home/user/task/scenes/_gen.tscn; godot --headless --path . res://scenes/test.tscn 2>&1 | grep -E "VALIDATION|SCRIPT ERROR|Parse Error" | head
output
VALIDATION_PASSED: Checkpoint beacon works correctly

[stdout]
VALIDATION_PASSED: Checkpoint beacon works correctly
Validation passes. Done. I built the checkpoint beacon across two files: **`scripts/checkpoint.gd`** , the `Checkpoint` class (`extends Area2D`): - Exports `checkpoint_id` (0), `is_final_checkpoint` (false), `charge_gradient`, `scale_curve`, `beacon`, `charge_label`; public `is_active` (false). - `apply_charge(t)` sets `beacon.modulate` from the gradient and `beacon.scale` from the curve. - `_on_body_entered` ignores non-`"Player"` bodies, lights an unlit checkpoint once (full charge, writes id to label, emits `activated`), also emits `level_complete` for a final checkpoint, and no-ops while lit. - `reset()` re-arms it. Signals `activated(id: int)` and `level_complete` declared. **`scenes/checkpoint.tscn`** , `Area2D` root `Checkpoint` with the script, a `CollisionShape2D` (32×32 `RectangleShape2D`), a `Beacon` `Sprite2D`, and a `ChargeLabel` `Label`. The `Gradient` (blue→cyan→white at 0/0.5/1) and `Curve` (1.0/1.8/2.0, `max_value=2.0`) are authored as sub-resources, the `beacon`/`charge_label` exports are wired via `node_paths`, and `body_entered` is connected to `_on_body_entered`. The project's validation runner (`scenes/test.tscn`) reports `VALIDATION_PASSED` under Godot 4.4. One thing worth flagging: the export node references only resolve when the root node header carries `node_paths=PackedStringArray("beacon", "charge_label")` , without it Godot leaves the properties null. That's the non-obvious bit if you ever hand-edit this scene again.
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_52f5c599ff9c4824. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_52f5c599ff9c4824 · verifier authoritative; classifier explanatory.