Run 54385280

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0009 USD — 19790 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6123 bytes)
import geopandas as gpd

def main():
    # Read the input parcels file
    parcels_gdf = gpd.read_file('parcels.geojson')
    
    # Create a 25 metre buffer around each parcel
    # Since the input is in EPSG:3857 (meters), the buffer distance is interpreted directly as meters
    buffers_gdf = parcels_gdf.buffer(25)
    
    # Write the buffered geometries to the output file
    buffers_gdf.to_file('simple_buffers.geojson')

if __name__ == "__main__":
    main()
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0009 USD — 21206 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input parcels file
parcels = gpd.read_file("parcels.geojson")

# Apply a 25 metre buffer to each geometry
# The CRS is 3857 (meters), so the distance is 25
parcels['geometry'] = parcels.geometry.buffer(25)

# Write the buffered geometries to the output file
parcels.to_file("simple_buffers.geojson")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0009 USD — 51128 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6123 bytes)
import geopandas as gpd

# Read the input parcels file
gdf = gpd.read_file("parcels.geojson")

# Create a 25 metre buffer around each parcel
# The CRS is EPSG:3857 (meters), so the distance is interpreted as meters
buffered_gdf = gdf.buffer(25)

# Write the buffered features to the output file
buffered_gdf.to_file("simple_buffers.geojson")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0009 USD — 53061 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6123 bytes)
import geopandas as gpd

def main():
    # Read the input file
    parcels = gpd.read_file("parcels.geojson")
    
    # Create a 25 metre buffer around every parcel
    # The CRS is 3857 (meters), so the distance is interpreted correctly
    buffers = parcels.buffer(distance=25)
    
    # Write the output file preserving the CRS
    buffers.to_file("simple_buffers.geojson")

if __name__ == "__main__":
    main()
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0009 USD — 27897 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6123 bytes)
import geopandas as gpd

# Read the input parcels file
parcels = gpd.read_file("parcels.geojson")

# Create a 25 metre buffer around each parcel
# The buffer distance is interpreted in the CRS units (meters for EPSG:3857)
buffered_parcels = parcels.buffer(distance=25)

# Write the buffered features to the output file
buffered_parcels.to_file("simple_buffers.geojson")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0010 USD — 31099 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input file
gdf = gpd.read_file("parcels.geojson")

# Ensure the CRS is EPSG:3857
gdf = gdf.to_crs(epsg=3857)

# Create a 25 metre buffer around each polygon
gdf['geometry'] = gdf.buffer(25)

# Write the output file
gdf.to_file("simple_buffers.geojson")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0019 USD — 42214 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input file
gdf = gpd.read_file('parcels.geojson')

# Apply a 25-meter buffer to the geometry
# Since the input is in EPSG:3857, the buffer distance is interpreted as meters
gdf['geometry'] = gdf.buffer(25)

# Write the output file
gdf.to_file('simple_buffers.geojson')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Import the geopandas library.",
    "Read the 'parcels.geojson' file into a GeoDataFrame.",
    "Apply a 25-meter buffer to the geometry column of the GeoDataFrame.",
    "Write the resulting buffered GeoDataFrame to 'simple_buffers.geojson'."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Verify that 'simple_buffers.geojson' exists in the working directory.",
    "Verify that the number of features in the output file matches the input file.",
    "Verify that the Coordinate Reference System (CRS) of the output file is EPSG:3857."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0018 USD — 54932 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Load the input file
gdf = gpd.read_file('parcels.geojson')

# Ensure the Coordinate Reference System is EPSG:3857
gdf = gdf.to_crs('EPSG:3857')

# Apply a 25 metre buffer to every parcel polygon
gdf['geometry'] = gdf.buffer(25)

# Write the buffered geometries to the output file
gdf.to_file('simple_buffers.geojson')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Load the input file 'parcels.geojson' into a GeoDataFrame, explicitly setting the Coordinate Reference System (CRS) to EPSG:3857.",
    "Apply a 25-meter buffer to every geometry in the GeoDataFrame using the 'buffer' method.",
    "Write the resulting buffered GeoDataFrame to the output file 'simple_buffers.geojson' while preserving the CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm that 'simple_buffers.geojson' exists in the working directory.",
    "Verify that the output GeoDataFrame contains the same number of features as the input.",
    "Check that the output CRS is EPSG:3857.",
    "Ensure all geometries in the output are valid and non-empty."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0018 USD — 33134 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6123 bytes)
import geopandas as gpd

# Load the input file
parcels = gpd.read_file('parcels.geojson')

# Apply a 25 metre buffer to every polygon
buffers = parcels.buffer(25)

# Write the result to the output file
buffers.to_file('simple_buffers.geojson')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Load 'parcels.geojson' into a GeoDataFrame.",
    "Apply a 25-meter buffer to the geometry column.",
    "Write the result to 'simple_buffers.geojson'."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that 'simple_buffers.geojson' exists.",
    "Verify the output feature count matches the input.",
    "Verify the output CRS is EPSG:3857."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0033 USD — 61499 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6123 bytes)
import geopandas as gpd

# Load the input file
gdf = gpd.read_file('parcels.geojson')

# Apply a 25-meter buffer to all geometries
# The input is assumed to be in EPSG:3857 (meters), so the buffer radius is 25
gdf = gdf.buffer(25)

# Write the resulting GeoDataFrame to the output file
gdf.to_file('simple_buffers.geojson')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Load 'parcels.geojson' into a GeoDataFrame.",
    "Verify the CRS is EPSG:3857.",
    "Apply a 25-meter buffer to all geometries using the buffer method.",
    "Write the resulting GeoDataFrame to 'simple_buffers.geojson'."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm 'simple_buffers.geojson' exists in the working directory.",
    "Confirm the output file contains the same number of features as the input.",
    "Confirm the output CRS is EPSG:3857."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0036 USD — 62159 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Load the input file
parcels = gpd.read_file('parcels.geojson')

# Ensure the CRS is EPSG:3857 as requested
if parcels.crs is None:
    parcels = parcels.set_crs('EPSG:3857')
elif parcels.crs.to_epsg() != 3857:
    parcels = parcels.to_crs('EPSG:3857')

# Apply a 25-meter buffer to every geometry
parcels['geometry'] = parcels.buffer(25)

# Write the output file
parcels.to_file('simple_buffers.geojson')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Load the input file 'parcels.geojson' into a GeoDataFrame using geopandas.",
    "Verify the CRS is set to EPSG:3857.",
    "Apply a 25-meter buffer to every geometry in the GeoDataFrame.",
    "Write the resulting buffered GeoDataFrame to 'simple_buffers.geojson'."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm 'simple_buffers.geojson' exists in the working directory.",
    "Verify the output GeoDataFrame has the same number of features as the input.",
    "Check that the output CRS is EPSG:3857.",
    "Ensure all geometries are valid polygons."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0023 USD — 87900 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Load the input file
parcels = gpd.read_file('parcels.geojson')

# Verify CRS is EPSG:3857
if parcels.crs is None:
    parcels = parcels.to_crs('EPSG:3857')
else:
    assert parcels.crs == 'EPSG:3857', "Input CRS is not EPSG:3857"

# Apply 25 metre buffer
parcels['geometry'] = parcels.buffer(25.0)

# Write output
parcels.to_file('simple_buffers.geojson')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Load the input file 'parcels.geojson' into a GeoDataFrame.",
    "Verify the Coordinate Reference System (CRS) is EPSG:3857 to ensure the buffer distance is interpreted in metres.",
    "Apply a 25.0 metre buffer to all geometries in the GeoDataFrame.",
    "Write the buffered GeoDataFrame to the output file 'simple_buffers.geojson', preserving the original CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm the existence of 'simple_buffers.geojson'.",
    "Compare the number of features in the input and output files.",
    "Verify the output CRS is EPSG:3857.",
    "Check that all geometries in the output are valid."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-4.7-flash — exit 0 — accepted — cost 0.0041 USD — 100211 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
import shapely

# Read the input file 'parcels.geojson'
gdf = gpd.read_file('parcels.geojson')

# Ensure the GeoDataFrame is in EPSG:3857 (projected) to calculate metres
if gdf.crs is None or gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

# Apply a 25-metre buffer to the geometry column
gdf['geometry'] = gdf.geometry.buffer(25)

# Write the buffered GeoDataFrame to 'simple_buffers.geojson'
gdf.to_file('simple_buffers.geojson')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Import geopandas and shapely libraries.",
    "Read the input file 'parcels.geojson' into a GeoDataFrame.",
    "Ensure the GeoDataFrame is in EPSG:3857 (projected) to calculate metres.",
    "Apply a 25-metre buffer to the geometry column.",
    "Write the buffered GeoDataFrame to 'simple_buffers.geojson'."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm 'simple_buffers.geojson' exists in the working directory.",
    "Verify the output file is a valid GeoJSON.",
    "Confirm the CRS of the output is EPSG:3857.",
    "Confirm the number of features matches the input."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0003 USD — 8182 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf.set_crs(epsg=3857, inplace=True)
gdf = gdf.to_crs(epsg=3857)
buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0003 USD — 9923 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf.set_crs("EPSG:3857", inplace=True)
gdf = gdf.to_crs("EPSG:3857")
buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0003 USD — 11450 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf = gdf.set_crs("EPSG:3857")
else:
    gdf = gdf.to_crs("EPSG:3857")

buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0003 USD — 12598 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf.set_crs("EPSG:3857", inplace=True)
else:
    gdf = gdf.to_crs("EPSG:3857")

buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0003 USD — 8111 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf.set_crs(epsg=3857, inplace=True)
else:
    gdf = gdf.to_crs(epsg=3857)

buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0010 USD — 16239 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf = gdf.set_crs("EPSG:3857")
else:
    gdf = gdf.to_crs("EPSG:3857")

gdf = gdf.dropna(subset=[gdf.geometry.name])
gdf = gdf[gdf.is_valid]

buffered = gdf.copy()
buffered.geometry = gdf.buffer(25)
buffered = buffered.set_crs("EPSG:3857", allow_override=True)

buffered.to_file("simple_buffers.geojson", driver="GeoJSON")

out = gpd.read_file("simple_buffers.geojson")
assert len(out) == len(gdf)
assert out.crs == "EPSG:3857"
architecture=plan-then-act
stage=planner
plan={"steps":["Import geopandas and shapely.","Read parcels.geojson using geopandas.read_file, ensuring CRS is EPSG:3857.","Verify the input GeoDataFrame contains polygon or multipolygon geometries and no missing geometries.","Create a 25 metre buffer around every parcel geometry using GeoDataFrame.buffer(25).","Replace the active geometry column with the buffered geometries while preserving all original attributes.","Ensure the output GeoDataFrame CRS remains EPSG:3857.","Write the result to simple_buffers.geojson using GeoDataFrame.to_file with driver GeoJSON.","Confirm the output file has one feature per input parcel and the same CRS."],"libraries":["geopandas","shapely","pyproj"],"validation":["Confirm parcels.geojson is readable and has CRS EPSG:3857.","Confirm the number of output features equals the number of input parcels.","Confirm all output geometries are valid buffered polygons or multipolygons.","Confirm simple_buffers.geojson is written and declares CRS EPSG:3857.","Confirm no input attributes are lost and no fabricated geometries are added."]}
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0003 USD — 20970 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf.set_crs("EPSG:3857", inplace=True)
else:
    gdf = gdf.to_crs("EPSG:3857")

buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 1 — rejected — cost 0.0010 USD — 25720 ms
# verifier: FAIL — simple buffer inputs unreadable
# no artifact produced
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None:
    gdf.set_crs(epsg=3857, inplace=True, allow_override=True)
elif gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
buffered = buffered.set_geometry("geometry")
buffered = buffered[buffered.geometry.notna() & ~buffered.geometry.is_empty]

assert len(buffered) == len(gdf), "Feature count mismatch"
assert buffered.crs.to_epsg() == 3857, "Output CRS is not EPSG:3857"
assert buffered.geometry.geom_type.isin(["Polygon", "MultiPolygon"]).all(), "Invalid geometry types"
assert buffered.geometry.is_valid.all(), "Invalid geometries"

for orig_geom, buf_geom in zip(gdf.geometry, buffered.geometry):
    assert buf_geom.intersects(orig_geom), "Buffered geometry does not intersect original"

buffered.to_file("simple_buffers.geojson", driver="GeoJSON", crs="EPSG:3857")
architecture=plan-then-act
stage=planner
plan={"steps":["Load parcels.geojson with geopandas.read_file.","Ensure the GeoDataFrame CRS is EPSG:3857; if missing or different, reproject to EPSG:3857 using to_crs.","Buffer each parcel geometry by 25 metres using GeoDataFrame.geometry.buffer(25).","Assign buffered geometries to a new GeoDataFrame, preserving all original attributes and the projected CRS.","Write the result to simple_buffers.geojson with the CRS set to EPSG:3857."],"libraries":["geopandas","shapely","pyproj"],"validation":["Confirm input feature count equals output feature count.","Confirm output CRS is EPSG:3857.","Confirm every output geometry is a valid Polygon or MultiPolygon and is non-empty.","Confirm each buffered geometry contains or intersects the corresponding original parcel geometry."]}
stage=act
--- execution stdout ---

--- stderr ---
Traceback (most recent call last):
  File "/tmp/arena/solution.py", line 22, in <module>
    buffered.to_file("simple_buffers.geojson", driver="GeoJSON", crs="EPSG:3857")
  File "/usr/local/lib/python3.11/site-packages/geopandas/geodataframe.py", line 1632, in to_file
    _to_file(self, filename, driver, schema, index, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/geopandas/io/file.py", line 731, in _to_file
    _to_file_pyogrio(df, filename, driver, schema, crs, mode, metadata, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/geopandas/io/file.py", line 787, in _to_file_pyogrio
    raise ValueError("Passing 'crs' is not supported with the 'pyogrio' engine.")
ValueError: Passing 'crs' is not supported with the 'pyogrio' engine.

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0011 USD — 24070 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None or gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

input_count = len(gdf)
buffered = gdf.copy()
buffered["geometry"] = gdf.geometry.buffer(25)
buffered = buffered.set_crs(epsg=3857, allow_override=True)

assert len(buffered) == input_count
assert buffered.crs.to_epsg() == 3857
assert buffered.geometry.notna().all()
assert buffered.geometry.is_valid.all()
assert not buffered.geometry.is_empty.any()

buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan={"steps":["Read parcels.geojson using geopandas.read_file.","Ensure the GeoDataFrame CRS is EPSG:3857; if missing or different, reproject to EPSG:3857 using to_crs.","Create a 25 metre buffer around every parcel geometry using GeoDataFrame.buffer(25).","Replace the geometry column with the buffered geometries while preserving all original attributes and row order.","Set the GeoDataFrame CRS to EPSG:3857 to preserve the projected CRS.","Write the result to simple_buffers.geojson using to_file(driver='GeoJSON').","Verify the output has the same number of features as the input and that all geometries are valid polygons."],"libraries":["geopandas","shapely","pyproj"],"validation":["Confirm input feature count equals output feature count.","Confirm output CRS is EPSG:3857.","Confirm every output geometry is a valid shapely geometry and is non-empty.","Confirm no input attributes were dropped beyond the geometry replacement."]}
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0017 USD — 28817 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
if gdf.crs is None or gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

buffered = gdf.copy()
buffered["geometry"] = buffered.buffer(25)
buffered = buffered.set_crs(epsg=3857, allow_override=True)

buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Import geopandas and shapely.",
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file.",
    "Verify the GeoDataFrame CRS is EPSG:3857; if not, reproject to EPSG:3857.",
    "Create a 25 metre buffer around every parcel polygon using GeoDataFrame.buffer(25).",
    "Assign the buffered geometries to the GeoDataFrame geometry column, preserving one feature per input parcel.",
    "Ensure the output GeoDataFrame retains the projected CRS EPSG:3857.",
    "Write the result to simple_buffers.geojson using GeoDataFrame.to_file with driver='GeoJSON'."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm simple_buffers.geojson exists in the working directory.",
    "Confirm the number of features in simple_buffers.geojson equals the number of features in parcels.geojson.",
    "Confirm the output CRS is EPSG:3857.",
    "Confirm each output geometry is a valid Polygon or MultiPolygon with a buffer distance of 25 metres.",
    "Confirm no input parcels were dropped and no fabricated geometries were added."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0022 USD — 34532 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.validation import make_valid

gdf = gpd.read_file("parcels.geojson")

if gdf.crs is None:
    gdf = gdf.set_crs("EPSG:3857")
elif gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs("EPSG:3857")

gdf["geometry"] = gdf["geometry"].apply(lambda geom: make_valid(geom) if not geom.is_valid else geom)

buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)
if buffered.crs is None:
    buffered = buffered.set_crs("EPSG:3857")

buffered.to_file("simple_buffers.geojson", driver="GeoJSON")

out = gpd.read_file("simple_buffers.geojson")
assert len(out) == len(gdf), "Feature count mismatch"
assert out.crs is not None and out.crs.to_epsg() == 3857, "Output CRS is not EPSG:3857"
assert out.geometry.is_valid.all(), "Output contains invalid geometries"
assert not out.geometry.is_empty.any(), "Output contains empty geometries"
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Import geopandas and shapely.",
    "Read parcels.geojson using geopandas.read_file.",
    "Ensure the GeoDataFrame CRS is EPSG:3857; if missing or different, reproject to EPSG:3857 using to_crs('EPSG:3857').",
    "Verify all geometries are valid polygons/multipolygons; if any invalid geometries exist, repair them with shapely.geometry.validation.make_valid or buffer(0) without dropping features.",
    "Create a 25 metre buffer around every parcel geometry using GeoDataFrame.geometry.buffer(25).",
    "Replace the geometry column with the buffered geometries while preserving all original attributes and row order.",
    "Set the GeoDataFrame CRS to EPSG:3857 to preserve the projected CRS.",
    "Write the result to simple_buffers.geojson using to_file(driver='GeoJSON'), ensuring one buffered feature per input parcel.",
    "Validate the output by reading simple_buffers.geojson, confirming feature count equals input feature count, CRS is EPSG:3857, and all geometries are valid and non-empty."
  ],
  "libraries": [
    "geopandas",
    "shapely",
    "pyproj"
  ],
  "validation": [
    "Input feature count equals output feature count.",
    "Output CRS is EPSG:3857.",
    "All output geometries are valid and non-empty.",
    "No input features were dropped or fabricated.",
    "Each output geometry corresponds to a 25 metre buffer of its input parcel."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/zai-org/glm-5.2 — exit 0 — accepted — cost 0.0025 USD — 38514 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import os
import geopandas as gpd

# Read input
gdf = gpd.read_file("parcels.geojson")

# Ensure EPSG:3857
if gdf.crs is None:
    gdf = gdf.set_crs(epsg=3857)
elif gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

input_count = len(gdf)

# Create 25m buffer
buffered = gdf.copy()
buffered["geometry"] = gdf.geometry.buffer(25)
buffered = buffered.set_geometry("geometry")
buffered = buffered.set_crs(epsg=3857)

# Write output
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")

# Validation
out = gpd.read_file("simple_buffers.geojson")
assert os.path.exists("simple_buffers.geojson"), "Output file not created"
assert len(out) == input_count, f"Feature count mismatch: {len(out)} != {input_count}"
assert out.crs is not None and out.crs.to_epsg() == 3857, f"Output CRS not EPSG:3857: {out.crs}"
for geom in out.geometry:
    assert geom is not None and not geom.is_empty, "Empty geometry found"
    assert geom.geom_type in ("Polygon", "MultiPolygon"), f"Invalid geometry type: {geom.geom_type}"
    assert geom.is_valid, "Invalid geometry found"

# Check buffer size relative to original
for orig, buf in zip(gdf.geometry, out.geometry):
    assert buf.area >= orig.area, "Buffered geometry smaller than original"

print("Validation passed")
architecture=full-multi-agent
stage=planner
plan={"steps":["Import geopandas and shapely.","Read parcels.geojson into a GeoDataFrame using geopandas.read_file.","Ensure the GeoDataFrame is in EPSG:3857 by checking .crs and reprojecting with to_crs(epsg=3857) if needed.","Create a 25 metre buffer around every parcel polygon using .buffer(25), assigning the result to a new geometry column or replacing the active geometry.","Preserve all original parcel attributes and maintain one output feature per input parcel.","Set the buffered geometries as the active geometry while keeping the CRS as EPSG:3857.","Write the result to simple_buffers.geojson using to_file(driver='GeoJSON').","Verify the output file exists, has the expected feature count, and has CRS EPSG:3857."],"libraries":["geopandas","shapely"],"validation":["Confirm simple_buffers.geojson was created in the working directory.","Confirm the output feature count equals the input feature count from parcels.geojson.","Confirm the output CRS is EPSG:3857.","Confirm every output geometry is a valid Polygon or MultiPolygon and is non-empty.","Confirm each buffered geometry is larger than or equal to the original parcel extent within a 25 metre buffer tolerance."]}
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---
Validation passed

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0004 USD — 4719 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file
parcels = gpd.read_file("parcels.geojson")

# Create a 25 meter buffer around each parcel polygon
# The CRS is already in EPSG:3857, so the buffer distance is in metres
parcels["geometry"] = parcels.geometry.buffer(25)

# Write the buffered geometries to the output GeoJSON file
parcels.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0005 USD — 5559 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input GeoJSON file
    parcels = gpd.read_file("parcels.geojson")

    # Create a 25-meter buffer around each parcel
    parcels["geometry"] = parcels.geometry.buffer(25)

    # Write the buffered geometries to the output GeoJSON file
    parcels.to_file("simple_buffers.geojson", driver="GeoJSON")

if __name__ == "__main__":
    main()
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0005 USD — 5602 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file (EPSG:3857)
gdf = gpd.read_file("parcels.geojson")

# Create a 25‑metre buffer around each parcel polygon
gdf["geometry"] = gdf.geometry.buffer(25)

# Write the buffered geometries to the output GeoJSON file, preserving the CRS
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0005 USD — 7922 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file
parcels = gpd.read_file("parcels.geojson")

# Create a 25 meter buffer around each parcel polygon
buffers = parcels.copy()
buffers["geometry"] = buffers.geometry.buffer(25)

# Write the buffered geometries to the output GeoJSON file
buffers.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0005 USD — 7262 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file
parcels = gpd.read_file('parcels.geojson')

# Create a 25 meter buffer around each parcel polygon
parcels['geometry'] = parcels.geometry.buffer(25)

# Write the buffered features to the output GeoJSON file
parcels.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0012 USD — 7787 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Ensure the CRS is EPSG:3857
if gdf.crs is None or gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

# Apply a 25‑metre buffer to each geometry
buffered_gdf = gdf.copy()
buffered_gdf.geometry = buffered_gdf.geometry.buffer(25)

# Write the buffered geometries to a new GeoJSON file
buffered_gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Import geopandas as gpd and shapely.geometry.",
    "Read the input GeoJSON file 'parcels.geojson' using gpd.read_file, ensuring the CRS is EPSG:3857.",
    "Apply a 25‑metre buffer to each geometry with the .buffer(25) method, preserving the CRS.",
    "Create a new GeoDataFrame containing the buffered geometries, keeping all original attributes.",
    "Write the resulting GeoDataFrame to 'simple_buffers.geojson' with gdf.to_file, specifying driver='GeoJSON' and ensuring the CRS remains EPSG:3857."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm that the output file 'simple_buffers.geojson' exists and contains the same number of features as the input.",
    "Verify that each feature's geometry is a Polygon or MultiPolygon and that its area is larger than the original.",
    "Check that the CRS of the output is EPSG:3857."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0005 USD — 8021 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Create a 25 meter buffer around each parcel polygon
gdf['geometry'] = gdf.geometry.buffer(25)

# Write the buffered geometries to the output GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0012 USD — 9490 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file
gdf = gpd.read_file("parcels.geojson")

# Ensure the CRS is EPSG:3857
if gdf.crs is None or gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

# Create a 25‑meter buffer around each geometry
gdf["geometry"] = gdf.geometry.buffer(25)

# Write the buffered geometries to a new GeoJSON file
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Import geopandas as gpd and shapely.geometry.",
    "Read the input file `parcels.geojson` using `gpd.read_file`, ensuring the CRS is EPSG:3857.",
    "Apply a 25‑meter buffer to each geometry with `gdf.geometry.buffer(25)`.",
    "Assign the buffered geometries back to the GeoDataFrame, preserving all original attributes.",
    "Write the resulting GeoDataFrame to `simple_buffers.geojson` with `to_file`, specifying `driver='GeoJSON'` and keeping the CRS unchanged.",
    "Optionally, verify that the output file exists and that each feature’s geometry is a Polygon or MultiPolygon."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that `simple_buffers.geojson` is created in the working directory.",
    "Load the output with `gpd.read_file` and confirm that the CRS is still EPSG:3857.",
    "Ensure that the number of features in the output matches the input and that all geometries are valid (e.g., `gdf.is_valid.sum()` equals the number of features)."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0011 USD — 10394 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON
gdf = gpd.read_file("parcels.geojson")

# Ensure the CRS is EPSG:3857
assert gdf.crs == "EPSG:3857", f"Unexpected CRS: {gdf.crs}"

# Apply a 25‑metre buffer to each geometry
gdf["geometry"] = gdf.geometry.buffer(25)

# Write the buffered geometries to the output GeoJSON
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file.",
    "Ensure the GeoDataFrame's CRS is EPSG:3857 (projected).",
    "Apply a 25‑metre buffer to each geometry: gdf['geometry'] = gdf.geometry.buffer(25).",
    "Write the resulting GeoDataFrame to simple_buffers.geojson with geopandas.to_file, preserving the CRS."
  ],
  "libraries": ["geopandas", "shapely"],
  "validation": [
    "Confirm that the output GeoDataFrame has the same number of rows as the input.",
    "Verify that each geometry in the output is a Polygon or MultiPolygon.",
    "Check that the CRS of the output file is EPSG:3857."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0023 USD — 11280 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import os
import geopandas as gpd

input_file = "parcels.geojson"
output_file = "simple_buffers.geojson"

if not os.path.isfile(input_file):
    raise FileNotFoundError(f"Input file '{input_file}' not found.")

gdf = gpd.read_file(input_file)

if gdf.crs.to_epsg() != 3857:
    raise ValueError(f"Input CRS is {gdf.crs}, expected EPSG:3857.")

buffered_geoms = gdf.geometry.buffer(25)

buffered_gdf = gpd.GeoDataFrame(gdf.drop(columns="geometry"), geometry=buffered_geoms, crs=gdf.crs)

buffered_gdf.to_file(output_file, driver="GeoJSON")

if not os.path.isfile(output_file):
    raise RuntimeError(f"Failed to create output file '{output_file}'.")
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file, ensuring the CRS is EPSG:3857.",
    "Apply a 25‑metre buffer to each geometry with the GeoDataFrame's .buffer(25) method (shapely is used under the hood).",
    "Assign the buffered geometries back to a new GeoDataFrame, preserving the original CRS.",
    "Write the resulting GeoDataFrame to simple_buffers.geojson with geopandas.GeoDataFrame.to_file, specifying driver='GeoJSON' and ensuring the CRS remains EPSG:3857."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm that the input file parcels.geojson exists and is readable.",
    "Verify that the output file simple_buffers.geojson is created and contains the same number of features as the input.",
    "Check that each geometry in the output is a Polygon or MultiPolygon and that the CRS is EPSG:3857."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0020 USD — 12460 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    gdf = gpd.read_file("parcels.geojson")
    if gdf.crs.to_epsg() != 3857:
        gdf = gdf.to_crs(epsg=3857)
    gdf["geometry"] = gdf.geometry.buffer(25)
    gdf.to_file("simple_buffers.geojson", driver="GeoJSON")

if __name__ == "__main__":
    main()
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file, ensuring the CRS is EPSG:3857.",
    "Apply a 25‑metre buffer to each geometry with the GeoDataFrame's .buffer(25) method, preserving the projected CRS.",
    "Write the resulting GeoDataFrame to simple_buffers.geojson with geopandas.GeoDataFrame.to_file, specifying driver='GeoJSON' and ensuring the CRS remains EPSG:3857."
  ],
  "libraries": ["geopandas", "shapely"],
  "validation": [
    "Confirm simple_buffers.geojson exists in the working directory.",
    "Verify that the number of features in simple_buffers.geojson equals the number of features in parcels.geojson.",
    "Check that the CRS of simple_buffers.geojson is EPSG:3857."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/openai/gpt-oss-20b — exit 0 — accepted — cost 0.0021 USD — 12848 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Ensure the CRS is EPSG:3857
if gdf.crs is None:
    gdf.set_crs(epsg=3857, inplace=True)
elif gdf.crs.to_epsg() != 3857:
    gdf = gdf.to_crs(epsg=3857)

# Apply a 25‑metre buffer to each geometry
gdf['geometry'] = gdf.geometry.buffer(25)

# Write the buffered geometries to a new GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file, ensuring the CRS is EPSG:3857.",
    "Apply a 25‑metre buffer to each geometry with the GeoDataFrame's .buffer(25) method, preserving the projected CRS.",
    "Write the resulting GeoDataFrame to simple_buffers.geojson with geopandas.GeoDataFrame.to_file, specifying driver='GeoJSON' and ensuring the CRS remains EPSG:3857."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm simple_buffers.geojson exists in the working directory.",
    "Verify that the number of features in simple_buffers.geojson equals the number in parcels.geojson.",
    "Check that the CRS of simple_buffers.geojson is EPSG:3857."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0008 USD — 10762 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input parcels file
gdf = gpd.read_file('parcels.geojson')

# Apply a 25 metre buffer to the geometries
# Since the input is in EPSG:3857, the buffer distance is interpreted in meters
gdf['geometry'] = gdf.buffer(25)

# Write the buffered geometries to the output file, preserving the CRS
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0007 USD — 13068 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input parcels file
gdf = gpd.read_file('parcels.geojson')

# Apply a 25 metre buffer
# The input is in EPSG:3857, so units are in meters
gdf['geometry'] = gdf.buffer(25)

# Write the output to simple_buffers.geojson
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0009 USD — 15521 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input parcels file
    gdf = gpd.read_file('parcels.geojson')
    
    # Apply a 25 metre buffer. 
    # Since the input is in EPSG:3857, the units are in meters.
    gdf['geometry'] = gdf.buffer(25)
    
    # Write the buffered geometries to the output file, preserving the CRS
    gdf.to_file('simple_buffers.geojson', driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0012 USD — 21561 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input parcels file
gdf = gpd.read_file('parcels.geojson')

# Create a 25 metre buffer around every parcel polygon
# The input is in EPSG:3857, which uses meters as units
gdf['geometry'] = gdf.buffer(25)

# Write the result to simple_buffers.geojson, preserving the CRS
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0006 USD — 11881 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input file
    gdf = gpd.read_file('parcels.geojson')
    
    # Ensure the CRS is EPSG:3857 as specified
    # If the file is already in 3857, this does nothing.
    # If it's not, we reproject to ensure the buffer is in meters.
    if gdf.crs is None or gdf.crs.to_epsg() != 3857:
        gdf = gdf.to_crs(epsg=3857)
    
    # Create a 25 metre buffer around every parcel polygon
    # Since the CRS is EPSG:3857, the units are meters.
    gdf['geometry'] = gdf.geometry.buffer(25)
    
    # Write the output file
    gdf.to_file('simple_buffers.geojson', driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0007 USD — 12108 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input parcels file
    gdf = gpd.read_file('parcels.geojson')
    
    # Create a 25 metre buffer. 
    # Since the input is in EPSG:3857, the units are already in meters.
    gdf['geometry'] = gdf.geometry.buffer(25)
    
    # Write the output to simple_buffers.geojson
    gdf.to_file('simple_buffers.geojson', driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0013 USD — 17062 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input file
    input_filename = 'parcels.geojson'
    output_filename = 'simple_buffers.geojson'
    
    gdf = gpd.read_file(input_filename)
    
    # Apply a 25-meter buffer
    # Since the input is in EPSG:3857, units are in meters
    gdf['geometry'] = gdf.geometry.buffer(25)
    
    # Save the resulting GeoDataFrame
    gdf.to_file(output_filename, driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read the input file 'parcels.geojson' into a GeoDataFrame using geopandas.",
    "Apply a 25-meter buffer to the geometry column of the GeoDataFrame using the .buffer() method.",
    "Save the resulting GeoDataFrame to 'simple_buffers.geojson' while preserving the EPSG:3857 CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Verify that the output file 'simple_buffers.geojson' is created.",
    "Confirm that the number of features in the output matches the number of features in the input.",
    "Check that the CRS of the output file remains EPSG:3857.",
    "Ensure the buffer distance applied is exactly 25 units (meters in EPSG:3857)."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0014 USD — 18738 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input file
    gdf = gpd.read_file('parcels.geojson')
    
    # Apply a 25-meter buffer
    # Since the input is in EPSG:3857 (meters), we can buffer directly by 25
    gdf['geometry'] = gdf.buffer(25)
    
    # Write the output file
    gdf.to_file('simple_buffers.geojson', driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read the input file 'parcels.geojson' into a GeoDataFrame using geopandas.",
    "Apply a 25-meter buffer operation to the geometry column of the GeoDataFrame using the .buffer() method.",
    "Ensure the CRS remains EPSG:3857 as specified.",
    "Write the resulting GeoDataFrame to 'simple_buffers.geojson' in GeoJSON format."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Verify that the number of features in the output file matches the number of features in the input file.",
    "Confirm that the CRS of the output file is EPSG:3857.",
    "Check that the geometries in the output are indeed buffered (e.g., by comparing area or bounding box)."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0014 USD — 17226 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input file
    input_filename = 'parcels.geojson'
    output_filename = 'simple_buffers.geojson'
    
    gdf = gpd.read_file(input_filename)
    
    # Ensure the CRS is EPSG:3857 as specified
    # If it's not, the buffer distance of 25 would not be in meters.
    # However, the prompt states it is in EPSG:3857.
    
    # Apply a 25 metre buffer
    # Since the CRS is EPSG:3857, units are in meters.
    gdf['geometry'] = gdf.geometry.buffer(25)
    
    # Write the output file preserving the CRS
    gdf.to_file(output_filename, driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read the input file 'parcels.geojson' into a GeoDataFrame using geopandas.",
    "Verify that the CRS is EPSG:3857 to ensure the buffer distance of 25 is interpreted as meters.",
    "Apply a buffer operation of 25 units to the geometry column of the GeoDataFrame using the .buffer() method.",
    "Write the resulting GeoDataFrame to 'simple_buffers.geojson' while preserving the original CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm the output file 'simple_buffers.geojson' is created.",
    "Verify that the number of features in the output matches the number of features in the input.",
    "Check that the CRS of the output file is EPSG:3857.",
    "Validate that the geometries in the output are indeed buffered versions of the input."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0014 USD — 18272 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input file
    input_filename = 'parcels.geojson'
    output_filename = 'simple_buffers.geojson'
    
    gdf = gpd.read_file(input_filename)
    
    # Apply a 25-meter buffer
    # Since the input is in EPSG:3857 (meters), we can buffer directly
    gdf['geometry'] = gdf.geometry.buffer(25)
    
    # Write the output file
    gdf.to_file(output_filename, driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read the input file 'parcels.geojson' into a GeoDataFrame using geopandas.",
    "Apply a 25-meter buffer to the geometry column of the GeoDataFrame using the .buffer() method.",
    "Save the resulting GeoDataFrame to 'simple_buffers.geojson' while preserving the original EPSG:3857 CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that 'simple_buffers.geojson' exists.",
    "Verify that the number of features in the output matches the number of features in the input.",
    "Confirm the CRS of the output file is EPSG:3857."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0033 USD — 33473 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input file
    gdf = gpd.read_file('parcels.geojson')
    
    # Ensure the CRS is EPSG:3857 as specified to ensure buffer is in meters
    if gdf.crs is None or gdf.crs.to_epsg() != 3857:
        gdf = gdf.to_crs(epsg=3857)
    
    # Apply a 25-meter buffer to the geometry column
    # We use gdf.geometry.buffer because GeoDataFrame itself does not have a .buffer method
    gdf['geometry'] = gdf.geometry.buffer(25)
    
    # Save the resulting GeoDataFrame to 'simple_buffers.geojson'
    gdf.to_file('simple_buffers.geojson', driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read the input file 'parcels.geojson' into a GeoDataFrame using geopandas.",
    "Verify the CRS is EPSG:3857 to ensure the buffer distance of 25 is interpreted as meters.",
    "Apply a 25-meter buffer to the geometry column of the GeoDataFrame using the .buffer() method.",
    "Save the resulting GeoDataFrame to 'simple_buffers.geojson' while preserving the original CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Verify that the number of features in the output file matches the number of features in the input file.",
    "Confirm the output CRS is EPSG:3857.",
    "Check that the geometries in the output file are indeed buffered versions of the input geometries."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0030 USD — 34176 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read the input file
gdf = gpd.read_file('parcels.geojson')

# Apply a 25-meter buffer to the geometry column
# Since the input is in EPSG:3857, units are in meters.
gdf['geometry'] = gdf.geometry.buffer(25)

# Save the resulting GeoDataFrame to 'simple_buffers.geojson'
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read the input file 'parcels.geojson' using geopandas.",
    "Apply a 25-meter buffer to the geometry column of the GeoDataFrame using the .buffer() method.",
    "Save the resulting GeoDataFrame to 'simple_buffers.geojson' while preserving the EPSG:3857 coordinate reference system."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Verify that the number of features in 'simple_buffers.geojson' matches the number of features in 'parcels.geojson'.",
    "Confirm that the CRS of the output file is EPSG:3857.",
    "Ensure that the buffer operation was applied to all geometries without dropping any rows."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/google/gemma-4-26b-a4b-it — exit 0 — accepted — cost 0.0044 USD — 111533 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    # Read the input file
    gdf = gpd.read_file('parcels.geojson')
    
    # Apply a 25 metre buffer
    # The input is in EPSG:3857, so the buffer distance of 25 is in meters
    gdf['geometry'] = gdf.geometry.buffer(25)
    
    # Write the resulting GeoDataFrame to the output file, preserving the CRS
    gdf.to_file('simple_buffers.geojson', driver='GeoJSON')

if __name__ == "__main__":
    main()
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read the input file 'parcels.geojson' into a GeoDataFrame using geopandas.",
    "Verify that the CRS is EPSG:3857 to ensure the buffer distance of 25 is interpreted as 25 meters.",
    "Apply the .buffer(25) operation to the geometry column of the GeoDataFrame.",
    "Write the resulting GeoDataFrame to 'simple_buffers.geojson' while preserving the CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm the output file 'simple_buffers.geojson' is created.",
    "Verify that the number of features in the output matches the number of features in the input.",
    "Check that the CRS of the output file remains EPSG:3857.",
    "Ensure no features or attributes were lost during the buffering process."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0008 USD — 17589 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

parcels = gpd.read_file("parcels.geojson")
buffered = parcels.copy()
buffered["geometry"] = buffered.buffer(25)
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0011 USD — 26604 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
gdf["geometry"] = gdf.buffer(25)
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — rejected — cost 0.0019 USD — 33860 ms
# verifier: FAIL — simple buffer inputs unreadable
# no artifact produced

architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0017 USD — 39217 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

parcels = gpd.read_file("parcels.geojson")
parcels["geometry"] = parcels.geometry.buffer(25)
parcels.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0008 USD — 17465 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
gdf["geometry"] = gdf.geometry.buffer(25)
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0019 USD — 35520 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
gdf["geometry"] = gdf.geometry.buffer(25)
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Load parcels.geojson into a GeoDataFrame with geopandas.read_file()",
    "Record the input CRS (EPSG:3857) for preservation",
    "Apply a 25-metre buffer to each geometry via gdf.geometry.buffer(25)",
    "Build the output GeoDataFrame using the buffered geometries while retaining all original attribute rows and the recorded CRS",
    "Write the output GeoDataFrame to simple_buffers.geojson using to_file(driver='GeoJSON')"
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "simple_buffers.geojson exists on disk",
    "Output feature count equals input feature count",
    "Output CRS is EPSG:3857",
    "No null or empty geometries in the output",
    "All output geometries are Polygon or MultiPolygon"
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0024 USD — 45037 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
original_count = len(gdf)
original_crs = gdf.crs

gdf.geometry = gdf.geometry.buffer(25)

assert len(gdf) == original_count, "Feature count changed after buffering"
assert gdf.crs == original_crs, "CRS was not preserved"

gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Load parcels.geojson into a GeoDataFrame using geopandas.read_file().",
    "Verify the GeoDataFrame CRS is EPSG:3857.",
    "Apply a 25-metre buffer to every geometry using GeoDataFrame.buffer(25).",
    "Ensure the resulting GeoDataFrame has the same row count as the input and retains original attributes.",
    "Write the buffered GeoDataFrame to simple_buffers.geojson with driver='GeoJSON', preserving the EPSG:3857 CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "simple_buffers.geojson exists on disk.",
    "Output GeoDataFrame CRS matches EPSG:3857.",
    "Output feature count equals input parcels.geojson feature count.",
    "No output geometries are None or empty.",
    "All output geometries are valid."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — rejected — cost 0.0019 USD — 38346 ms
# verifier: FAIL — simple buffer inputs unreadable
# no artifact produced

architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — rejected — cost 0.0019 USD — 73711 ms
# verifier: FAIL — simple buffer inputs unreadable
# no artifact produced

architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0027 USD — 50462 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
original_count = len(gdf)

assert gdf.crs is not None, "Input CRS is missing"
assert gdf.crs.to_epsg() == 3857, f"Expected EPSG:3857, got {gdf.crs}"

gdf["geometry"] = gdf.geometry.buffer(25)

assert len(gdf) == original_count, "Feature count mismatch"
assert gdf.crs.to_epsg() == 3857, "Output CRS was changed"
assert gdf.geometry.isna().sum() == 0, "Null geometries found in output"

gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file().",
    "Verify the GeoDataFrame's CRS is EPSG:3857.",
    "Apply a 25-metre buffer to every geometry using gdf.geometry.buffer(25).",
    "Construct a new GeoDataFrame with the buffered geometries, retaining all original rows and attributes, and explicitly preserve the EPSG:3857 CRS.",
    "Write the resulting GeoDataFrame to simple_buffers.geojson using to_file(driver='GeoJSON')."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm simple_buffers.geojson exists on disk.",
    "Assert the output feature count equals the input parcels.geojson feature count.",
    "Assert the output GeoDataFrame CRS is EPSG:3857.",
    "Assert no null geometries exist in the output.",
    "Assert all output geometries are valid Polygon or MultiPolygon types."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0042 USD — 71637 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")

if gdf.crs is None:
    gdf = gdf.set_crs(epsg=3857)

buffered = gdf.copy()
buffered.geometry = gdf.geometry.buffer(25)

buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Load parcels.geojson with geopandas.read_file() and verify its CRS is EPSG:3857.",
    "Apply a 25-metre buffer to each geometry using GeoDataFrame.buffer(25) to produce one buffered geometry per input parcel.",
    "Construct a new GeoDataFrame containing the buffered geometries, preserving original attributes and the EPSG:3857 CRS.",
    "Export the resulting GeoDataFrame to simple_buffers.geojson using to_file(driver='GeoJSON')."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm simple_buffers.geojson exists in the working directory.",
    "Assert the output feature count matches the input parcels.geojson feature count.",
    "Assert the output CRS is EPSG:3857.",
    "Assert no null or empty geometries exist in the output."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=false
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0056 USD — 81117 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read input
gdf = gpd.read_file('parcels.geojson')

# Verify CRS is EPSG:3857
if gdf.crs is None or gdf.crs.to_epsg() != 3857:
    raise ValueError(f"Expected EPSG:3857, got {gdf.crs}")

# Verify all geometries are Polygon or MultiPolygon
valid_types = {'Polygon', 'MultiPolygon'}
if not set(gdf.geom_type).issubset(valid_types):
    raise ValueError("Non-polygonal geometries found in input")

# Apply 25-metre buffer preserving all attributes
out = gdf.copy()
out['geometry'] = out.geometry.buffer(25)

# Confirm output integrity
assert len(out) == len(gdf), "Row count mismatch"
assert out.geometry.notna().all(), "Output contains null geometries"
assert (~out.geometry.is_empty).all(), "Output contains empty geometries"
assert set(out.geom_type).issubset(valid_types), "Output contains invalid geometry types"

# Preserve projected CRS
out.crs = gdf.crs

# Write result
out.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan={"steps":["Read parcels.geojson into a GeoDataFrame using geopandas.read_file.","Verify the input CRS is EPSG:3857 and that all features are polygonal geometries.","Apply a 25-metre buffer to each geometry via GeoDataFrame.buffer(25).","Build a new GeoDataFrame from the buffered geometries while preserving all original attributes and the EPSG:3857 CRS.","Confirm the output has the same row count as the input and contains no null or empty geometries.","Write the result to simple_buffers.geojson using to_file with driver='GeoJSON' and crs='EPSG:3857'."],"libraries":["geopandas","shapely"],"validation":["simple_buffers.geojson exists and is readable.","Output row count equals input row count.","Output CRS is EPSG:3857.","No null or empty geometries in the output.","All output geometries are Polygon or MultiPolygon types."]}
stage=builder
stage=auditor
auditor_output_present=false
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.6 — exit 0 — accepted — cost 0.0050 USD — 85937 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon, MultiPolygon

gdf = gpd.read_file("parcels.geojson")

if gdf.crs is None:
    gdf = gdf.set_crs(epsg=3857)
else:
    gdf = gdf.to_crs(epsg=3857)

buffers = gdf.copy()
buffers["geometry"] = gdf.geometry.buffer(25)

assert len(buffers) == len(gdf), "Row count mismatch"
assert buffers.crs.to_string() == "EPSG:3857", "CRS mismatch"
assert buffers.geometry.notna().all(), "Null geometries found"
assert (~buffers.geometry.is_empty).all(), "Empty geometries found"
assert all(isinstance(geom, (Polygon, MultiPolygon)) for geom in buffers.geometry), "Invalid geometry types"

buffers.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file().",
    "Verify the GeoDataFrame CRS is EPSG:3857; if missing, assign EPSG:3857.",
    "Apply a 25-metre buffer to each geometry using gdf.geometry.buffer(25) to produce a new GeoSeries.",
    "Construct a new GeoDataFrame from the buffered geometries, preserving all original columns/attributes and the EPSG:3857 CRS.",
    "Validate that the output GeoDataFrame has the same row count as the input and contains no null or empty geometries.",
    "Write the resulting GeoDataFrame to simple_buffers.geojson using to_file(driver='GeoJSON')."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Assert simple_buffers.geojson exists on disk.",
    "Assert the output feature count equals the input parcels.geojson feature count.",
    "Assert the output CRS is EPSG:3857.",
    "Assert no null geometries exist in the output.",
    "Assert all output geometries are valid Polygon or MultiPolygon types."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0004 USD — 8772 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
gdf["geometry"] = gdf.geometry.buffer(25)
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0003 USD — 10017 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
gdf["geometry"] = gdf.geometry.buffer(25)
gdf.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0005 USD — 12860 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")
gdf = gdf.set_crs(epsg=3857, allow_override=True)

buffered = gdf.copy()
buffered["geometry"] = buffered.geometry.buffer(25)

buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0008 USD — 16775 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
if gdf.crs is None:
    gdf = gdf.set_crs(epsg=3857)

gdf['geometry'] = gdf.buffer(25)

gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0005 USD — 9786 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf.geometry.buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0012 USD — 14472 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file("parcels.geojson")

assert gdf.crs is not None and gdf.crs.to_epsg() == 3857, "Input CRS must be EPSG:3857"

buffered = gdf.copy()
buffered.geometry = gdf.geometry.buffer(25)

assert len(buffered) == len(gdf), "Feature count must be preserved"
assert buffered.geometry.is_valid.all(), "All buffered geometries must be valid"
assert buffered.geometry.notna().all(), "No null geometries allowed"

buffered.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file().",
    "Verify the input CRS is EPSG:3857.",
    "Apply a 25-metre buffer to every parcel geometry using GeoDataFrame.geometry.buffer(25).",
    "Construct a new GeoDataFrame containing the buffered geometries and the original attributes, one row per input parcel.",
    "Assign the output CRS to EPSG:3857 to preserve the projected coordinate system.",
    "Write the result to simple_buffers.geojson using GeoDataFrame.to_file()."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Input and output feature counts are identical.",
    "Output CRS is EPSG:3857.",
    "No null or empty geometries exist in the output.",
    "All output geometries are valid polygons.",
    "Each buffered geometry is a 25-metre buffer of its corresponding input parcel."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0015 USD — 20112 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

def main():
    input_path = "parcels.geojson"
    output_path = "simple_buffers.geojson"

    gdf = gpd.read_file(input_path)

    if gdf.crs is None:
        gdf.set_crs(epsg=3857, inplace=True)
    elif gdf.crs.to_epsg() != 3857:
        gdf = gdf.to_crs(epsg=3857)

    gdf["geometry"] = gdf.geometry.buffer(25)

    assert gdf.crs.to_epsg() == 3857, "Output CRS must be EPSG:3857"
    assert not gdf.geometry.isna().any(), "Buffered geometries must not be null"

    gdf.to_file(output_path, driver="GeoJSON")

if __name__ == "__main__":
    main()
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file().",
    "Verify the GeoDataFrame CRS is EPSG:3857; if not, set/confirm it before buffering.",
    "Apply a 25-metre buffer to every parcel geometry using GeoDataFrame.geometry.buffer(25).",
    "Assign the buffered geometries back to the GeoDataFrame, preserving one output row per input parcel and all original attributes.",
    "Confirm the output GeoDataFrame retains the EPSG:3857 CRS and contains no fabricated or dropped features.",
    "Write the result to simple_buffers.geojson using GeoDataFrame.to_file(driver='GeoJSON') with CRS preserved."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "simple_buffers.geojson is created and readable by geopandas.",
    "Output CRS equals EPSG:3857.",
    "Output feature count equals input parcels.geojson feature count.",
    "Every output geometry is a valid Polygon or MultiPolygon and not null.",
    "No input parcels are dropped and no extra geometries are fabricated."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0013 USD — 25113 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
if gdf.crs is None:
    gdf = gdf.set_crs(epsg=3857)
gdf['geometry'] = gdf.geometry.buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0011 USD — 16751 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
import os

input_path = "parcels.geojson"
output_path = "simple_buffers.geojson"

gdf = gpd.read_file(input_path)

assert gdf.crs is not None, "Input CRS is missing"
assert gdf.crs.to_epsg() == 3857, f"Expected EPSG:3857, got {gdf.crs.to_epsg()}"

gdf["geometry"] = gdf.geometry.buffer(25.0)

gdf.to_file(output_path, driver="GeoJSON")
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Import geopandas and verify parcels.geojson is present in the working directory.",
    "Read parcels.geojson using geopandas.read_file() and confirm its CRS is EPSG:3857.",
    "Apply a 25-metre buffer to every parcel geometry using GeoDataFrame.buffer(25), preserving one output feature per input parcel.",
    "Assign the buffered geometries back to the GeoDataFrame, keeping all original attributes and the original projected CRS (EPSG:3857).",
    "Write the result to simple_buffers.geojson using GeoDataFrame.to_file(driver='GeoJSON') with CRS preserved."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Output file simple_buffers.geojson exists and is readable.",
    "Output CRS equals EPSG:3857.",
    "Output feature count matches input parcels.geojson feature count.",
    "Every output geometry is a valid Polygon or MultiPolygon and is non-empty.",
    "Each buffered geometry fully contains or equals its corresponding input parcel geometry."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0026 USD — 28528 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read input parcels
parcels = gpd.read_file("parcels.geojson")

# Verify CRS is EPSG:3857
assert parcels.crs is not None, "Input CRS is missing"
assert parcels.crs.to_epsg() == 3857, f"Expected EPSG:3857, got {parcels.crs.to_epsg()}"

# Create 25-metre buffers, preserving attributes and index
buffers = parcels.copy()
buffers.geometry = parcels.geometry.buffer(25)

# Validate output
assert len(buffers) == len(parcels), "Feature count mismatch"
assert buffers.crs.to_epsg() == 3857, "Output CRS must be EPSG:3857"
assert buffers.geometry.is_valid.all(), "Invalid geometries in output"
assert buffers.geometry.is_empty.sum() == 0, "Empty geometries in output"

# Verify each buffer fully contains its original parcel
assert buffers.geometry.contains(parcels.geometry, align=True).all(), "Not all buffers contain their original parcels"

# Write output GeoJSON
buffers.to_file("simple_buffers.geojson", driver="GeoJSON")
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Import geopandas and verify the working directory contains parcels.geojson.",
    "Read parcels.geojson using geopandas.read_file() and confirm the CRS is EPSG:3857.",
    "Apply a 25-metre buffer to every parcel geometry using GeoDataFrame.buffer(25), producing one buffered Polygon/MultiPolygon per input parcel.",
    "Construct a new GeoDataFrame from the buffered geometries, copying the original attributes/index to preserve feature correspondence.",
    "Set the CRS of the new GeoDataFrame to EPSG:3857 to preserve the projected coordinate system.",
    "Write the result to simple_buffers.geojson using GeoDataFrame.to_file(driver='GeoJSON')."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Input and output GeoDataFrames have the same number of features (no drops or fabricated geometries).",
    "Output CRS is EPSG:3857.",
    "Every output geometry is a valid Polygon or MultiPolygon and is non-empty.",
    "Each buffered geometry fully contains its corresponding original parcel geometry (buffer distance >= 25 m).",
    "Output file simple_buffers.geojson is written and readable by geopandas.read_file()."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 0 — accepted — cost 0.0028 USD — 32811 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

# Read input
gdf = gpd.read_file("parcels.geojson")

# Ensure projected CRS is EPSG:3857
if gdf.crs is None:
    gdf = gdf.set_crs("EPSG:3857")
elif gdf.crs.to_string() != "EPSG:3857":
    gdf = gdf.to_crs("EPSG:3857")

# Create 25-metre buffers
buffered = gdf.copy()
buffered.geometry = gdf.geometry.buffer(25)

# Write output
buffered.to_file("simple_buffers.geojson", driver="GeoJSON")

# Validation
assert len(buffered) == len(gdf), "Feature count mismatch"
assert buffered.crs.to_string() == "EPSG:3857", "CRS not preserved"
assert buffered.geometry.is_valid.all(), "Invalid geometries found"
assert buffered.geometry.notna().all(), "Null geometries found"
print("simple_buffers.geojson written successfully")
print("Input features:", len(gdf))
print("Output features:", len(buffered))
print("CRS:", buffered.crs.to_string())
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read parcels.geojson into a GeoDataFrame using geopandas.read_file.",
    "Verify the GeoDataFrame CRS is EPSG:3857; if missing or different, set/confirm it before buffering.",
    "Apply a 25-metre buffer to every parcel geometry using GeoDataFrame.geometry.buffer(25).",
    "Construct a new GeoDataFrame containing the buffered geometries and the original parcel attributes, preserving the EPSG:3857 CRS.",
    "Write the result to simple_buffers.geojson using to_file(driver='GeoJSON'), ensuring one buffered feature per input parcel."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Confirm the output feature count equals the input feature count.",
    "Confirm the output CRS is EPSG:3857.",
    "Confirm every output geometry is a valid Polygon/MultiPolygon and not null.",
    "Spot-check a few geometries to ensure they are visibly expanded by approximately 25 metres."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---
simple_buffers.geojson written successfully
Input features: 2
Output features: 2
CRS: EPSG:3857

# attempt undefined — model: @cf/moonshotai/kimi-k2.7-code — exit 1 — rejected — cost 0.0033 USD — 36613 ms
# verifier: FAIL — simple buffer inputs unreadable
# no artifact produced
import geopandas as gpd

# Load input parcels
gdf = gpd.read_file("parcels.geojson")

# Verify CRS is EPSG:3857
assert gdf.crs is not None, "Input CRS is missing"
input_epsg = gdf.crs.to_epsg()
assert input_epsg == 3857, f"Expected EPSG:3857, got {input_epsg}"

# Verify all geometries are valid Polygon/MultiPolygon and non-empty
assert gdf.geometry.is_valid.all(), "Input contains invalid geometries"
assert gdf.geometry.notna().all(), "Input contains null geometries"
assert (~gdf.geometry.is_empty).all(), "Input contains empty geometries"
allowed_types = {"Polygon", "MultiPolygon"}
for geom in gdf.geometry:
    assert geom.geom_type in allowed_types, f"Unsupported geometry type: {geom.geom_type}"

# Apply 25-metre buffer preserving attributes and CRS
buffered = gdf.copy()
buffered.geometry = gdf.geometry.buffer(25, cap_style=1, join_style=1)

# Validate output
assert len(buffered) == len(gdf), "Feature count mismatch after buffering"
assert buffered.crs is not None, "Output CRS is missing"
assert buffered.crs.to_epsg() == 3857, "Output CRS changed"
assert buffered.geometry.is_valid.all(), "Output contains invalid geometries"
assert buffered.geometry.notna().all(), "Output contains null geometries"
assert (~buffered.geometry.is_empty).all(), "Output contains empty geometries"
for geom in buffered.geometry:
    assert geom.geom_type in allowed_types, f"Unsupported output geometry type: {geom.geom_type}"

# Write output GeoJSON
buffered.to_file("simple_buffers.geojson", driver="GeoJSON", crs="EPSG:3857")
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Load parcels.geojson with geopandas.read_file and verify the CRS is EPSG:3857.",
    "Inspect the GeoDataFrame to confirm all geometries are Polygon/MultiPolygon types and that there are no null or empty geometries.",
    "Apply a 25-metre buffer to every geometry using GeoDataFrame.geometry.buffer(25) (or shapely.buffer with cap_style=1/join_style=1 for a standard rounded buffer).",
    "Construct a new GeoDataFrame containing the buffered geometries, preserving the original parcel attributes and the EPSG:3857 CRS.",
    "Write the result to simple_buffers.geojson using GeoDataFrame.to_file(driver='GeoJSON', crs='EPSG:3857')."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Input and output feature counts are identical (one buffered feature per input parcel).",
    "Output CRS is EPSG:3857 and matches the input CRS.",
    "All output geometries are valid Polygon or MultiPolygon geometries with no null or empty entries.",
    "Buffer distance is exactly 25 metres in the projected coordinate units.",
    "No features were dropped and no geometries were fabricated."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

--- stderr ---
Traceback (most recent call last):
  File "/tmp/arena/solution.py", line 34, in <module>
    buffered.to_file("simple_buffers.geojson", driver="GeoJSON", crs="EPSG:3857")
  File "/usr/local/lib/python3.11/site-packages/geopandas/geodataframe.py", line 1632, in to_file
    _to_file(self, filename, driver, schema, index, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/geopandas/io/file.py", line 731, in _to_file
    _to_file_pyogrio(df, filename, driver, schema, crs, mode, metadata, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/geopandas/io/file.py", line 787, in _to_file_pyogrio
    raise ValueError("Passing 'crs' is not supported with the 'pyogrio' engine.")
ValueError: Passing 'crs' is not supported with the 'pyogrio' engine.

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0003 USD — 7963 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Load the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Write the output GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0003 USD — 8742 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Write the output GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0003 USD — 8796 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Create a buffer of 25 meters around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Write the output GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0003 USD — 9132 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Load the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Write the output GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0003 USD — 7562 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Load the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Write the output GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0003 USD — 7669 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Load the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Create a buffer of 25 meters around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Save the result to a new GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0009 USD — 14330 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Ensure the data is in the correct projected CRS (EPSG:3857)
gdf = gdf.set_crs(epsg=3857, allow_override=True)

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Write the buffered geometries to a new GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read the input GeoJSON file 'parcels.geojson' using geopandas.",
    "Ensure the data is in the correct projected CRS (EPSG:3857).",
    "Create a 25-meter buffer around each parcel polygon using Shapely.",
    "Write the buffered geometries to a new GeoJSON file 'simple_buffers.geojson' preserving the projected CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that the input file 'parcels.geojson' exists and is readable.",
    "Verify that the output file 'simple_buffers.geojson' is created and contains the expected number of features.",
    "Ensure that each feature in the output file has a valid geometry and is a buffer of the corresponding input feature."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0009 USD — 16361 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Ensure the GeoDataFrame is in the correct CRS (EPSG:3857)
gdf = gdf.set_crs(epsg=3857, allow_override=True)

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Create a new GeoDataFrame with the buffered geometries
buffered_gdf = gdf.copy()

# Write the new GeoDataFrame to a GeoJSON file
buffered_gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read the input GeoJSON file 'parcels.geojson' into a GeoDataFrame.",
    "Ensure the GeoDataFrame is in the correct CRS (EPSG:3857).",
    "Create a 25-meter buffer around each parcel polygon using the Shapely library.",
    "Create a new GeoDataFrame with the buffered geometries.",
    "Write the new GeoDataFrame to a GeoJSON file named 'simple_buffers.geojson' with the same CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that the output GeoJSON file 'simple_buffers.geojson' contains the same number of features as the input file.",
    "Verify that each feature in the output file is a buffered version of the corresponding feature in the input file.",
    "Ensure the CRS of the output file is EPSG:3857."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0009 USD — 14467 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Read the parcels.geojson file into a GeoDataFrame
gdf = gpd.read_file('parcels.geojson')

# Ensure the GeoDataFrame is in the EPSG:3857 CRS
gdf = gdf.set_crs(epsg=3857, allow_override=True)

# Create a 25-metre buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Create a new GeoDataFrame with the buffered geometries
buffered_gdf = gdf.copy()

# Write the new GeoDataFrame to a file named simple_buffers.geojson, preserving the EPSG:3857 CRS
buffered_gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=plan-then-act
stage=planner
plan=```json
{
  "steps": [
    "Read the parcels.geojson file into a GeoDataFrame using geopandas.",
    "Ensure the GeoDataFrame is in the EPSG:3857 CRS.",
    "Create a 25-metre buffer around each parcel polygon using the buffer method from shapely.",
    "Create a new GeoDataFrame with the buffered geometries.",
    "Write the new GeoDataFrame to a file named simple_buffers.geojson, preserving the EPSG:3857 CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that the output file simple_buffers.geojson contains the same number of features as the input file parcels.geojson.",
    "Verify that each feature in the output file is a buffered version of the corresponding feature in the input file.",
    "Ensure that the CRS of the output file is EPSG:3857."
  ]
}
```
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0015 USD — 15828 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Ensure the data is in the correct projected CRS (EPSG:3857)
gdf = gdf.to_crs(epsg=3857)

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].buffer(25)

# Write the buffered geometries to a new GeoJSON file while preserving the projected CRS
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read the input GeoJSON file 'parcels.geojson' using GeoPandas.",
    "Ensure the data is in the correct projected CRS (EPSG:3857).",
    "Create a 25-meter buffer around each parcel polygon using Shapely.",
    "Write the buffered geometries to a new GeoJSON file 'simple_buffers.geojson' while preserving the projected CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that the input file 'parcels.geojson' exists and is readable.",
    "Verify that the output file 'simple_buffers.geojson' contains the same number of features as the input file.",
    "Ensure that each feature in the output file has a buffered geometry."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 1 — rejected — cost 0.0015 USD — 17084 ms
# verifier: FAIL — simple buffer inputs unreadable
# no artifact produced
import geopandas as gpd
from shapely.geometry import Polygon

# Read the input GeoJSON file
gdf = gpd.read_file('parcels.geojson')

# Ensure the data is in the correct projected CRS (EPSG:3857)
gdf = gdf.to_crs(epsg=3857, allow_duplicates=True)

# Create a 25-meter buffer around each parcel polygon
gdf['geometry'] = gdf['geometry'].apply(lambda geom: geom.buffer(25))

# Write the buffered geometries to a new GeoJSON file
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read the input GeoJSON file 'parcels.geojson' using geopandas.",
    "Ensure the data is in the correct projected CRS (EPSG:3857).",
    "Create a 25-meter buffer around each parcel polygon using shapely.",
    "Write the buffered geometries to a new GeoJSON file 'simple_buffers.geojson' preserving the projected CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that the input file 'parcels.geojson' exists and is readable.",
    "Verify that the output file 'simple_buffers.geojson' is created and contains the expected number of features.",
    "Ensure that each feature in the output file has a valid geometry and is a buffer of the corresponding input feature."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

--- stderr ---
Traceback (most recent call last):
  File "/tmp/arena/solution.py", line 8, in <module>
    gdf = gdf.to_crs(epsg=3857, allow_duplicates=True)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: GeoDataFrame.to_crs() got an unexpected keyword argument 'allow_duplicates'

# attempt undefined — model: @cf/mistralai/mistral-small-3.1-24b-instruct — exit 0 — accepted — cost 0.0015 USD — 17652 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd
from shapely.geometry import Polygon

# Read the input GeoJSON file
parcels = gpd.read_file('parcels.geojson')

# Ensure the data is in the correct projected CRS (EPSG:3857)
parcels = parcels.to_crs(epsg=3857)

# Create a 25-metre buffer around each parcel polygon
parcels['geometry'] = parcels['geometry'].buffer(25)

# Write the buffered geometries to a new GeoJSON file
parcels.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan=```json
{
  "steps": [
    "Read the input GeoJSON file 'parcels.geojson' using geopandas.",
    "Ensure the data is in the correct projected CRS (EPSG:3857).",
    "Create a 25-metre buffer around each parcel polygon using shapely.",
    "Write the buffered geometries to a new GeoJSON file 'simple_buffers.geojson' preserving the projected CRS."
  ],
  "libraries": [
    "geopandas",
    "shapely"
  ],
  "validation": [
    "Check that the input file 'parcels.geojson' exists and is readable.",
    "Verify that the output file 'simple_buffers.geojson' is created and contains the expected number of features.",
    "Ensure that each feature in the output file has a valid geometry and is a buffer of the corresponding input feature."
  ]
}
```
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0008 USD — 13845 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

parcels = gpd.read_file('parcels.geojson')
buffers = parcels.copy()
buffers['geometry'] = buffers.geometry.buffer(25)
buffers.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0008 USD — 14709 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

parcels = gpd.read_file('parcels.geojson')
buffers = parcels.copy()
buffers['geometry'] = buffers.geometry.buffer(25)
buffers.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0008 USD — 17023 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf.buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-shot
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0010 USD — 18111 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf.buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0008 USD — 11179 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

parcels = gpd.read_file('parcels.geojson')
buffers = parcels.copy()
buffers['geometry'] = buffers.geometry.buffer(25)
buffers.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0016 USD — 15347 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf['geometry'].buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=plan-then-act
stage=planner
plan={"steps":["Read 'parcels.geojson' into a GeoDataFrame using geopandas","Create a 25-meter buffer around each geometry using shapely's buffer method","Preserve the original CRS (EPSG:3857) in the output GeoDataFrame","Write the buffered geometries to 'simple_buffers.geojson'"],"libraries":["geopandas","shapely"],"validation":["Verify output file 'simple_buffers.geojson' exists","Check that CRS matches EPSG:3857","Ensure number of features equals input parcel count"]}
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0009 USD — 17342 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf.geometry.buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=single-retry
stage=single-code-generation
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0017 USD — 26243 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

parcels = gpd.read_file('parcels.geojson')
parcels['geometry'] = parcels.geometry.buffer(25)
parcels.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=plan-then-act
stage=planner
plan={"steps":["Read 'parcels.geojson' into a GeoDataFrame using geopandas","Create a 25-meter buffer around each geometry in the GeoDataFrame using shapely's buffer method","Preserve the original CRS (EPSG:3857) in the output GeoDataFrame","Write the buffered GeoDataFrame to 'simple_buffers.geojson'"],"libraries":["geopandas","shapely"],"validation":["Verify output file 'simple_buffers.geojson' exists","Check CRS of output matches EPSG:3857","Ensure number of features equals input parcel count"]}
stage=act
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 1 — rejected — cost 0.0022 USD — 27317 ms
# verifier: FAIL — simple buffer inputs unreadable
# no artifact produced
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf.geometry.buffer(25)
gdf.to_file('simple_buffers.geojson', crs='EPSG:3857')
architecture=plan-then-act
stage=planner
plan={"steps":["Read 'parcels.geojson' into a GeoDataFrame using geopandas.","Create a 25-meter buffer around each geometry using the buffer method.","Write the buffered GeoDataFrame to 'simple_buffers.geojson' with EPSG:3857 CRS."],"libraries":["geopandas","shapely"],"validation":["Verify 'simple_buffers.geojson' exists and has same feature count as input.","Check output CRS is EPSG:3857.","Ensure no geometries are null or dropped during buffering."]}
stage=act
--- execution stdout ---

--- stderr ---
Traceback (most recent call last):
  File "/tmp/arena/solution.py", line 5, in <module>
    gdf.to_file('simple_buffers.geojson', crs='EPSG:3857')
  File "/usr/local/lib/python3.11/site-packages/geopandas/geodataframe.py", line 1632, in to_file
    _to_file(self, filename, driver, schema, index, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/geopandas/io/file.py", line 731, in _to_file
    _to_file_pyogrio(df, filename, driver, schema, crs, mode, metadata, **kwargs)
  File "/usr/local/lib/python3.11/site-packages/geopandas/io/file.py", line 787, in _to_file_pyogrio
    raise ValueError("Passing 'crs' is not supported with the 'pyogrio' engine.")
ValueError: Passing 'crs' is not supported with the 'pyogrio' engine.

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0029 USD — 29563 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

parcels = gpd.read_file('parcels.geojson')
buffered = parcels.copy()
buffered.geometry = buffered.geometry.buffer(25)
buffered.crs = 'EPSG:3857'
buffered.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan={"steps":["Read 'parcels.geojson' into a GeoDataFrame using geopandas","Create a 25-meter buffer around each geometry using shapely's buffer method","Preserve original attributes and projected CRS (EPSG:3857) in new GeoDataFrame","Write buffered geometries to 'simple_buffers.geojson' as GeoJSON"],"libraries":["geopandas","shapely"],"validation":["Verify output file contains same number of features as input","Check CRS of output matches EPSG:3857","Ensure all geometries are valid and non-empty"]}
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0028 USD — 43880 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf.geometry.buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan={"steps":["Read 'parcels.geojson' into a GeoDataFrame using geopandas","Create 25-meter buffer around each geometry in the 'geometry' column","Write the resulting GeoDataFrame to 'simple_buffers.geojson'"],"libraries":["geopandas","shapely"],"validation":["Verify output file 'simple_buffers.geojson' exists","Check CRS of output matches EPSG:3857","Ensure number of features equals input file"]}
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---

# attempt undefined — model: @cf/qwen/qwen3-30b-a3b-fp8 — exit 0 — accepted — cost 0.0030 USD — 44362 ms
# verifier: PASS — simple buffer geometry verified
# artifact: download (6171 bytes)
import geopandas as gpd

gdf = gpd.read_file('parcels.geojson')
gdf['geometry'] = gdf.geometry.buffer(25)
gdf.to_file('simple_buffers.geojson', driver='GeoJSON')
architecture=full-multi-agent
stage=planner
plan={"steps":["Read parcels.geojson using geopandas","Create 25-meter buffer around each geometry with geopandas.GeoDataFrame.buffer","Write resulting GeoDataFrame to simple_buffers.geojson"],"libraries":["geopandas","shapely"],"validation":["Verify output file exists","Check CRS matches input (EPSG:3857)","Ensure all original features are preserved with buffered geometries"]}
stage=builder
stage=auditor
auditor_output_present=true
--- execution stdout ---