SyncValsverifier → artifact → classifier → verdict
SyncVals · Trajectory

car-scene-assembly

claude-code claude-opus-4-8 ✗ failed BAD_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
BAD_FAILUREThe task is at fault, underspecified/contradictory instruction, brittle/flaky tests, or tests demanding undiscoverable behavior.
SubtypeUnderspecified Instruction
EvidenceThe instruction.md says to "find the correct forward-facing vertical car body in the spritesheet" but does not specify which car. The test.gd hardcodes the expected region as `Rect2(291, 0, 70, 133)` with radius 34 and height 138. The agent inspected the spritesheet, found the top-left car at `Rect2(0, 0, 70, 130)`, and implemented it reasonably. The test failed with message "VALIDATION_FAILED: Wrong car selected , find the correct forward-facing vertical car body in the spritesheet" but provided no additional guidance about which specific region is correct. The required region coordinates (291, 0, 70, 133) are not mentioned in instruction.md and cannot be discovered from the buggy codebase alone, they only exist in the hidden test validation script.
Root causeThe instruction asks the agent to find "the correct" car in the spritesheet without specifying which one (by region coordinates). The agent must reverse-engineer this from the test, which they cannot see. The specific region Rect2(291, 0, 70, 133) is only defined in the hidden test.gd and is impossible for the agent to discover.
RecommendationAdd the specific region coordinates to instruction.md. Change 'find the correct forward-facing vertical car body' to 'find the forward-facing car at region Rect2(291, 0, 70, 133) in the spritesheet' OR improve the test failure message to include the correct region so agents can iterate when they pick the wrong car."
Trajectory
Tool-by-tool agent trajectory
43 tool calls · 3 tool types · 43 steps
# Car Scene Assembly In scenes/car.tscn, keep the CharacterBody2D named Car as the root and add the following hierarchy. Add a Sprite2D as the first child: use res://assets/spritesheet_vehicles.png, enable region cropping to isolate the forward-facing car sprite from the sheet, and rotate it 90° so the car faces forward. Add a CollisionShape2D sibling at the default position with a CapsuleShape2D sized to closely match the car sprite, also rotated 90°. Finally, add a Camera2D child of Car at the origin with no offset.
Read
{
  "file_path": "/home/user/task/scenes/car.tscn"
}
output
1	[gd_scene load_steps=1 format=3 uid="uid://codexcarsetupscene"]
2	
3	[node name="Car" type="CharacterBody2D"]
4
Bash
ls /home/user/task && echo "---ASSETS---" && ls /home/user/task/assets 2>/dev/null && echo "---SCENES---" && ls /home/user/task/scenes 2>/dev/null

{
  "description": "List project files and assets"
}
output
assets
project.godot
scenes
scripts
tmp_check.gd.uid
---ASSETS---
spritesheet_vehicles.png
spritesheet_vehicles.png.import
---SCENES---
car.tscn
main.tscn
test.tscn

[stdout]
assets
project.godot
scenes
scripts
tmp_check.gd.uid
---ASSETS---
spritesheet_vehicles.png
spritesheet_vehicles.png.import
---SCENES---
car.tscn
main.tscn
test.tscn
Read
{
  "file_path": "/home/user/task/assets/spritesheet_vehicles.png.import"
}
output
1	[remap]
2	
3	importer="texture"
4	type="CompressedTexture2D"
5	uid="uid://4j3r3nq5e1ub"
6	path="res://.godot/imported/spritesheet_vehicles.png-e16a3162cc0edb8275366b9e44a79438.ctex"
7	metadata={
8	"vram_texture": false
9	}
10	
11	[deps]
12	
13	source_file="res://assets/spritesheet_vehicles.png"
14	dest_files=["res://.godot/imported/spritesheet_vehicles.png-e16a3162cc0edb8275366b9e44a79438.ctex"]
15	
16	[params]
17	
18	compress/mode=0
19	compress/high_quality=false
20	compress/lossy_quality=0.7
21	compress/hdr_compression=1
22	compress/normal_map=0
23	compress/channel_pack=0
24	mipmaps/generate=false
25	mipmaps/limit=-1
26	roughness/mode=0
27	roughness/src_normal=""
28	process/fix_alpha_border=true
29	process/premult_alpha=false
30	process/normal_map_invert_y=false
31	process/hdr_as_srgb=false
32	process/hdr_clamp_exposure=false
33	process/size_limit=0
34	detect_3d/compress_to=1
35
Read
{
  "file_path": "/home/user/task/assets/spritesheet_vehicles.png"
}
output
{"type": "image", "source": {"type": "base64", "data": "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…[truncated]
Read
{
  "file_path": "/home/user/task/scenes/main.tscn"
}
output
1	[gd_scene load_steps=2 format=3 uid="uid://codexcarsetupmain"]
2	
3	[ext_resource type="PackedScene" path="res://scenes/car.tscn" id="1_j7vsa"]
4	
5	[node name="Main" type="Node2D"]
6	
7	[node name="Car" parent="." instance=ExtResource("1_j7vsa")]
8
Bash
python3 -c "
from PIL import Image
im = Image.open('assets/spritesheet_vehicles.png')
print('size', im.size, 'mode', im.mode)
" 2>/dev/null || (command -v identify >/dev/null && identify assets/spritesheet_vehicles.png) || file assets/spritesheet_vehicles.png

{
  "description": "Get spritesheet dimensions"
}
output
Exit code 127
/bin/bash: line 9: file: command not found

[error] tool reported failure
Bash
python3 - <<'EOF'
import struct
with open('assets/spritesheet_vehicles.png','rb') as f:
    data=f.read(33)
# PNG IHDR
w,h=struct.unpack('>II', data[16:24])
print('width',w,'height',h)
EOF

{
  "description": "Read PNG IHDR dimensions"
}
output
width 1024 height 512

[stdout]
width 1024 height 512
Bash
pip install pillow -q 2>/dev/null; python3 - <<'EOF'
from PIL import Image
im = Image.open('assets/spritesheet_vehicles.png').convert('RGBA')
W,H = im.size
px = im.load()
# find bounding box of top-left connected sprite via flood fill from (10,10)
from collections import deque
def alpha(x,y): return px[x,y][3]>10
# Find top-left car: scan first column region. The first car occupies roughly x in [0,~64]
# Let's flood fill the connected component containing the first opaque pixel near top-left.
start=None
for y in range(H):
    for x in range(W):
        if alpha(x,y):
            start=(x,y); break
    if start: break
print('first opaque', start)
seen=set([start])
q=deque([start])
minx=miny=10**9; maxx=maxy=-1
while q:
    x,y=q.popleft()
    minx=min(minx,x);maxx=max(maxx,x);miny=min(miny,y);maxy=max(maxy,y)
    for dx in(-1,0,1):
        for dy in(-1,0,1):
            nx,ny=x+dx,y+dy
            if 0<=nx<W and 0<=ny<H and (nx,ny) not in seen and alpha(nx,ny):
                seen.add((nx,ny));q.append((nx,ny))
print('bbox x',minx,maxx,'y',miny,maxy,'w',maxx-minx+1,'h',maxy-miny+1)
EOF

{
  "description": "Find top-left car sprite bounding box"
}
output
Exit code 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'PIL'

[error] tool reported failure
Bash
pip install pillow 2>&1 | tail -2

{
  "description": "Install pillow"
}
output
/bin/bash: line 1: pip: command not found

[stdout]
/bin/bash: line 1: pip: command not found
Bash
python3 -m pip install pillow 2>&1 | tail -3; python3 -c "import sys; print(sys.version)"

{
  "description": "Install pillow via python -m pip"
}
output
/usr/bin/python3: No module named pip
3.12.3 (main, Mar 23 2026, 19:04:32) [GCC 13.3.0]

[stdout]
/usr/bin/python3: No module named pip
3.12.3 (main, Mar 23 2026, 19:04:32) [GCC 13.3.0]
Bash
python3 - <<'EOF'
import zlib, struct
from collections import deque
f=open('assets/spritesheet_vehicles.png','rb').read()
assert f[:8]==b'\x89PNG\r\n\x1a\n'
i=8
W=H=bitd=ct=None
idat=b''
while i<len(f):
    ln=struct.unpack('>I',f[i:i+4])[0]
    typ=f[i+4:i+8]
    data=f[i+8:i+8+ln]
    if typ==b'IHDR':
        W,H,bitd,ct=struct.unpack('>IIBB',data[:10])
    elif typ==b'IDAT':
        idat+=data
    elif typ==b'IEND':
        break
    i+=12+ln
print('W',W,'H',H,'bitdepth',bitd,'colortype',ct)
raw=zlib.decompress(idat)
# color type 6 = RGBA, 8bit -> 4 bytes/px
ch=4 if ct==6 else (3 if ct==2 else None)
assert ch, ct
stride=W*ch
# unfilter
out=bytearray()
prev=bytearray(stride)
def paeth(a,b,c):
    p=a+b-c;pa=abs(p-a);pb=abs(p-b);pc=abs(p-c)
    return a if pa<=pb and pa<=pc else (b if pb<=pc else c)
pos=0
for y in range(H):
    ft=raw[pos];pos+=1
    line=bytearray(raw[pos:pos+stride]);pos+=stride
    if ft==1:
        for x in range(ch,stride): line[x]=(line[x]+line[x-ch])&255
    elif ft==2:
        for x in range(stride): line[x]=(line[x]+prev[x])&255
    elif ft==3:
        for x in range(stride):
            a=line[x-ch] if x>=ch else 0
            line[x]=(line[x]+((a+prev[x])>>1))&255
    elif ft==4:
        for x in range(stride):
            a=line[x-ch] if x>=ch else 0
            c=prev[x-ch] if x>=ch else 0
            line[x]=(line[x]+paeth(a,prev[x],c))&255
    out+=line
    prev=line
# alpha accessor
def alpha(x,y):
    if ch==4:
        return out[(y*W+x)*4+3]>10
    return True
# save for reuse
import pickle
pickle.dump((W,H,ch,bytes(out)),open('/tmp/img.pkl','wb'))
# top-left connected component
start=None
for y in range(H):
    for x in range(W):
        if alpha(x,y): start=(x,y);break
    if start:break
print('first',start)
seen={start};q=deque([start]);minx=miny=10**9;maxx=maxy=-1
while q:
    x,y=q.popleft()
    minx=min(minx,x);maxx=max(maxx,x);miny=min(miny,y);maxy=max(maxy,y)
    for dx in(-1,0,1):
        for dy in(-1,0,1):
            nx,ny=x+dx,y+dy
            if 0<=nx<W and 0<=ny<H and (nx,ny) not in seen and alpha(nx,ny):
                seen.add((nx,ny));q.append((nx,ny))
print('topleft bbox x[%d..%d] y[%d..%d] w=%d h=%d'%(minx,maxx,miny,maxy,maxx-minx+1,maxy-miny+1))
EOF

{
  "description": "Decode PNG and find top-left car bbox"
}
output
W 1024 H 512 bitdepth 8 colortype 6
first (22, 0)
topleft bbox x[0..689] y[0..511] w=690 h=512

[stdout]
W 1024 H 512 bitdepth 8 colortype 6
first (22, 0)
topleft bbox x[0..689] y[0..511] w=690 h=512
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
# Examine first-row band. Find row separations first: scan each row's opaque count across x[0..700]
rows=[]
for y in range(H):
    c=sum(1 for x in range(0,700) if a(x,y))
    rows.append(c)
# print rows where count is low (gaps)
gaps=[y for y in range(H) if rows[y]<20]
print('low-density rows:',gaps)
EOF

{
  "description": "Find horizontal row gaps"
}
output
low-density rows: []

[stdout]
low-density rows: []
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
# column density in top band y[0..118]
band=range(0,118)
dens=[sum(1 for y in band if a(x,y)) for x in range(0,720)]
# find local minima / low columns
for x in range(0,720):
    if dens[x]<8:
        print('lowcol',x,dens[x])
EOF

{
  "description": "Column density in top band"
}
output
lowcol 675 0
lowcol 676 0
lowcol 677 0
lowcol 678 0
lowcol 679 0
lowcol 680 0
lowcol 681 0
lowcol 682 0
lowcol 683 0
lowcol 684 0
lowcol 685 0
lowcol 686 0
lowcol 687 0
lowcol 688 0
lowcol 689 0
lowcol 690 0
lowcol 691 0
lowcol 692 0
lowcol 693 0
lowcol 694 0
lowcol 695 0
lowcol 696 0
lowcol 697 0
lowcol 698 0
lowcol 699 0
lowcol 700 0
lowcol 701 0
lowcol 702 0
lowcol 703 0
lowcol 704 0
lowcol 705 0
lowcol 706 0
lowcol 707 0
lowcol 708 0
lowcol 709 0
lowcol 710 0
lowcol 711 0
lowcol 712 0
lowcol 713 0
lowcol 714 0
lowcol 715 0
lowcol 716 0
lowcol 717 0
lowcol 718 0
lowcol 719 0

[stdout]
lowcol 675 0
lowcol 676 0
lowcol 677 0
lowcol 678 0
lowcol 679 0
lowcol 680 0
lowcol 681 0
lowcol 682 0
lowcol 683 0
lowcol 684 0
lowcol 685 0
lowcol 686 0
lowcol 687 0
lowcol 688 0
lowcol 689 0
lowcol 690 0
lowcol 691 0
lowcol 692 0
lowcol 693 0
lowcol 694 0
lowcol 695 0
lowcol 696 0
lowcol 697 0
lowcol 698 0
lowcol 699 0
lowcol 700 0
lowcol 701 0
lowcol 702 0
lowcol 703 0
lowcol 704 0
lowcol 705 0
lowcol 706 0
lowcol 707 0
lowcol 708 0
lowcol 709 0
lowcol 710 0
lowcol 711 0
lowcol 712 0
lowcol 713 0
lowcol 714 0
lowcol 715 0
lowcol 716 0
lowcol 717 0
lowcol 718 0
lowcol 719 0
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
band=range(0,118)
dens=[sum(1 for y in band if a(x,y)) for x in range(0,680)]
# print as compact rows of 10
for x in range(0,680,1):
    pass
# find local minima below threshold relative to neighbors
mins=[]
for x in range(2,678):
    if dens[x]<=dens[x-1] and dens[x]<=dens[x+1] and dens[x]<60:
        mins.append((x,dens[x]))
print('candidate boundary cols (low density):')
print(mins)
EOF

{
  "description": "Find local minima boundary columns"
}
output
candidate boundary cols (low density):
[(70, 34), (72, 32), (73, 32), (143, 34), (145, 30), (146, 30), (216, 32), (217, 32), (219, 37), (288, 24), (289, 24), (291, 37), (360, 24), (361, 24), (506, 51), (507, 51), (546, 32), (548, 31), (549, 31), (589, 57), (591, 54), (673, 25), (675, 0), (676, 0), (677, 0)]

[stdout]
candidate boundary cols (low density):
[(70, 34), (72, 32), (73, 32), (143, 34), (145, 30), (146, 30), (216, 32), (217, 32), (219, 37), (288, 24), (289, 24), (291, 37), (360, 24), (361, 24), (506, 51), (507, 51), (546, 32), (548, 31), (549, 31), (589, 57), (591, 54), (673, 25), (675, 0), (676, 0), (677, 0)]
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
# vertical density in left column band x[0..72]
band=range(0,72)
dens=[sum(1 for x in band if a(x,y)) for y in range(0,H)]
mins=[]
for y in range(2,H-2):
    if dens[y]<=dens[y-1] and dens[y]<=dens[y+1] and dens[y]<40:
        mins.append((y,dens[y]))
print('row boundary candidates:', mins[:30])
EOF

{
  "description": "Find row boundaries in left column"
}
output
row boundary candidates: [(130, 26), (131, 26), (133, 27), (250, 27), (251, 27), (381, 26), (382, 26), (384, 27), (501, 0), (502, 0), (503, 0), (504, 0), (505, 0), (506, 0), (507, 0), (508, 0), (509, 0)]

[stdout]
row boundary candidates: [(130, 26), (131, 26), (133, 27), (250, 27), (251, 27), (381, 26), (382, 26), (384, 27), (501, 0), (502, 0), (503, 0), (504, 0), (505, 0), (506, 0), (507, 0), (508, 0), (509, 0)]
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
# tight bbox within cell x[0..71] y[0..130]
minx=miny=10**9;maxx=maxy=-1
for y in range(0,131):
    for x in range(0,72):
        if a(x,y):
            minx=min(minx,x);maxx=max(maxx,x);miny=min(miny,y);maxy=max(maxy,y)
print('car1 tight bbox x[%d..%d] y[%d..%d] w=%d h=%d'%(minx,maxx,miny,maxy,maxx-minx+1,maxy-miny+1))
EOF

{
  "description": "Tight bbox of first car within its cell"
}
output
car1 tight bbox x[0..71] y[0..130] w=72 h=131

[stdout]
car1 tight bbox x[0..71] y[0..130] w=72 h=131
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
for y in [40,60,90]:
    row=''.join('#' if a(x,y) else '.' for x in range(0,150))
    print(y, row)
EOF

{
  "description": "Visualize opaque spans across first two cars"
}
output
40 .#####################################################################....#####################################################################....###
60 ..###################################################################......###################################################################......##
90 .####################################################################.....####################################################################.....###

[stdout]
40 .#####################################################################....#####################################################################....###
60 ..###################################################################......###################################################################......##
90 .####################################################################.....####################################################################.....###
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
col=''.join('#' if a(35,y) else '.' for y in range(0,260))
print(col)
# spans
y=0;spans=[]
inside=False
for yy in range(0,260):
    v=a(35,yy)
    if v and not inside: s=yy;inside=True
    if not v and inside: spans.append((s,yy-1));inside=False
if inside: spans.append((s,259))
print('vertical opaque spans at x=35:',spans)
EOF

{
  "description": "Vertical span of first car center column"
}
output
####################################################################################################################################################################################################################################################################
vertical opaque spans at x=35: [(0, 259)]

[stdout]
####################################################################################################################################################################################################################################################################
vertical opaque spans at x=35: [(0, 259)]
Bash
python3 - <<'EOF'
import pickle
W,H,ch,out=pickle.load(open('/tmp/img.pkl','rb'))
def a(x,y): return out[(y*W+x)*4+3]>10
for y in range(118,140):
    row=''.join('#' if a(x,y) else '.' for x in range(0,72))
    print(y, row)
EOF

{
  "description": "Inspect rows between car1 and car2"
}
output
118 ########################################################################
119 .#######################################################################
120 .#####################################################################..
121 .#####################################################################..
122 ..####################################################################..
123 ..###################################################################...
124 ...#################################################################....
125 ....################################################################....
126 .....#############################################################......
127 ......###########################################################.......
128 ........#######################################################.........
129 .............#############################################..............
130 .......................##########################.......................
131 .......................##########################.......................
132 ......................###########################.......................
133 ......................###########################.......................
134 ............###############################################.............
135 .........#####################################################..........
136 .......#########################################################........
137 ......###########################################################.......
138 .....#############################################################......
139 ....###############################################################.....

[stdout]
118 ########################################################################
119 .#######################################################################
120 .#####################################################################..
121 .#####################################################################..
122 ..####################################################################..
123 ..###################################################################...
124 ...#################################################################....
125 ....################################################################....
126 .....#############################################################......
127 ......###########################################################.......
128 ........#######################################################.........
129 .............#############################################..............
130 .......................##########################.......................
131 .......................##########################.......................
132 ......................###########################.......................
133 ......................###########################.......................
134 ............###############################################.............
135 .........#####################################################..........
136 .......#########################################################........
137 ......###########################################################.......
138 .....#############################################################......
139 ....###############################################################.....
Now I have what I need. The top-left forward-facing (pointing-up) car occupies region `(0,0,70,130)`, cells are tightly packed but x70–73 / y130–133 are the inter-car waists, so that rect isolates it cleanly. Let me write the scene.
Write
{
  "file_path": "/home/user/task/scenes/car.tscn",
  "content": "[gd_scene load_steps=3 format=3 uid=\"uid://codexcarsetupscene\"]\n\n[ext_resource type=\"Texture2D\" uid=\"uid://4j3r3nq5e1ub\" path=\"res://assets/spritesheet_vehicles.png\" id=\"1_car\"]\n\n[sub_resource type=\"CapsuleShape2D\" id=\"CapsuleShape2D_car\"]\nradius = 35.0\nheight = 130.0\n\n[node name=\"Car\" type=\"CharacterBody2D\"]\n\n[node name=\"Sprite2D\" type=\"Sprite2D\" parent=\".\"]\nrotation = 1.5707963267948966\ntexture = ExtResource(\"1_car\")\nregion_enabled = true\nregion_rect = Rect2(0, 0, 70, 130)\n\n[node name=\"CollisionShape2D\" type=\"CollisionShape2D\" parent=\".\"]\nrotation = 1.5707963267948966\nshape = SubResource(\"CapsuleShape2D_car\")\n\n[node name=\"Camera2D\" type=\"Camera2D\" parent=\".\"]\n"
}
output
The file /home/user/task/scenes/car.tscn has been updated successfully. (file state is current in your context , no need to Read it back)
Done. `scenes/car.tscn` now assembles the full hierarchy under the existing `Car` (CharacterBody2D) root: - **Sprite2D** (first child) , uses `spritesheet_vehicles.png` with `region_enabled = true` and `region_rect = Rect2(0, 0, 70, 130)`, which isolates the top-left forward-facing (originally up-pointing) sedan. I verified against the decoded PNG that this rect lands exactly on that car: the inter-car gaps fall at columns 70–73 and the vertical waist at rows 130–133, so neighbors don't bleed in. Rotated `+90°` (1.5708 rad) so the car faces forward (+X). - **CollisionShape2D** (sibling, default position 0,0) , `CapsuleShape2D` with `radius = 35` / `height = 130`, matching the 70×130 sprite, also rotated 90° so its long axis aligns with the now horizontally-facing car. - **Camera2D** (child of Car) , at the origin, no offset (all defaults). `load_steps` is set to 3 (1 ext_resource + 1 sub_resource + 1), and the texture reference reuses the asset's existing import UID. One judgment call worth flagging: I rotated `+90°` (clockwise) so forward = +X, the standard Godot 2D convention. If your movement code treats a different axis as forward, say so and I'll flip the sign.
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: Wrong car selected , find the correct forward-facing vertical car body in the spritesheet

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_7d6a2170af56475b. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_7d6a2170af56475b · verifier authoritative; classifier explanatory.