SyncVals · Trajectory

checkpoint-system

claude-code claude-opus-4-8 ✗ failed GOOD_FAILURE ↑ 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_FAILUREHonest miss, the agent ran correctly but couldn't solve it. Expected for a hard task; the task is sound.

SubtypeWrong Approach

EvidenceTest failure message: 'beacon export must be wired to the Beacon Sprite2D in the scene'. The agent created the checkpoint.tscn with `beacon = NodePath("Beacon")` and `charge_label = NodePath("ChargeLabel")`, but the test validator at line 48-50 checks `if beacon_ref == null or not (beacon_ref is Sprite2D)`, expecting actual node references, not NodePath strings. The validator test is correct and properly wired node references are required by the instruction ('each wired in the scene to the Beacon and ChargeLabel nodes').

Root causeThe agent misunderstood Godot's scene serialization format and used NodePath string assignments instead of actual node references. In Godot, NodePath() creates a path reference (serializes as a string), not a direct node object reference, causing the validator's type check to fail.

RecommendationN/A - task is fine

Trajectory

Tool-by-tool agent trajectory

14 tool calls · 3 tool types · 14 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. Let me start with the script, then author the scene.

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 the player lights a checkpoint flagged as the level's final one.\nsignal level_complete\n\n@export var checkpoint_id: int = 0\n@export var is_final_checkpoint: bool = false\n\n## Colors the beacon as it charges (sampled by charge fraction).\n@export var charge_gradient: Gradient\n## Scales the beacon as it charges (sampled by charge fraction).\n@export var scale_curve: Curve\n\n## Scene-wired references to the visual nodes.\n@export var beacon: Sprite2D\n@export var charge_label: Label\n\n## True once lit; cleared by reset() so it can be lit again.\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: Node) -> void:\n\t# Only the player can light a checkpoint, and only while it is unlit.\n\tif is_active or not body.is_in_group(\"Player\"):\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

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

Both files exist as stubs. Let me replace them.

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 the player lights a checkpoint flagged as the level's final one.\nsignal level_complete\n\n@export var checkpoint_id: int = 0\n@export var is_final_checkpoint: bool = false\n\n## Colors the beacon as it charges (sampled by charge fraction).\n@export var charge_gradient: Gradient\n## Scales the beacon as it charges (sampled by charge fraction).\n@export var scale_curve: Curve\n\n## Scene-wired references to the visual nodes.\n@export var beacon: Sprite2D\n@export var charge_label: Label\n\n## True once lit; cleared by reset() so it can be lit again.\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: Node) -> void:\n\t# Only the player can light a checkpoint, and only while it is unlit.\n\tif is_active or not body.is_in_group(\"Player\"):\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)

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_checkpoint\"]\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_checkpoint\")\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)

Both files are done. Summary of what I built: **`scripts/checkpoint.gd`** , `Checkpoint` class (`extends Area2D`): - Signals `activated(id: int)` and `level_complete`. - 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 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` when final. - `reset()` clears `is_active`. **`scenes/checkpoint.tscn`** , `Checkpoint` (`Area2D`) with the script attached, the `charge_gradient` (blue→cyan→white at 0/0.5/1) and `scale_curve` (1.0/1.8/2.0, `max_value` raised to 2.0) authored as sub-resources, `beacon`/`charge_label` wired to the child nodes, a 32×32 `RectangleShape2D` `CollisionShape2D`, a `Beacon` `Sprite2D`, a `ChargeLabel` `Label`, and the `body_entered → _on_body_entered` connection. One note: the `Beacon` `Sprite2D` has no texture assigned (none was specified), so it won't render until you give it one , the pulsing modulate/scale logic is fully wired regardless.

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_FAILED: beacon export must be wired to the Beacon Sprite2D in the scene

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_301fee52f01b4bd8. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_301fee52f01b4bd8 · verifier authoritative; classifier explanatory.