SyncVals · Trajectory

game-of-life-step

codex gpt-5.5 ✓ resolved GOOD_SUCCESS ↑ View task

Solved from the instruction alone, tests/ and solution/ were withheld from the agent's workspace and restored only for grading.

Reward = tests/test.sh exit code (0 → resolved); the classification below is post-hoc and cannot change it.

Classification , post-hoc; cannot change the reward

GOOD_SUCCESSLegitimate solve, implements the asked-for behavior; tests verify real functionality.

SubtypeLegitimate Solution

EvidenceAgent implemented toroidal Game of Life correctly: (1) reads grid.csv and config.json, (2) preserves walls (value 2), (3) counts only living neighbors (value 1) with wrap-around via modulo arithmetic, (4) applies Conway rules (live with 2-3 neighbors, birth with 3), (5) iterates generations, (6) writes output/next.csv. All 6 tests pass: test_output_exists, test_shipped_dimensions_and_values, test_shipped_walls_preserved, test_shipped_correct (verifies correctness against independent _evolve reference), test_not_identity_copy, and test_hidden_alternates (12 seeded cases with various board sizes and wall configurations). Agent trajectory shows systematic exploration (read stub, inspected data files, implemented logic, verified syntax and output shape) with no shortcuts or hardcoding. Implementation differs stylistically from reference solution but is functionally equivalent.

Root causeAgent correctly understood the complex task specification (toroidal topology, wall semantics, wrap-around neighbor counting, simultaneous updates, generation iteration) and implemented a complete, working solution that passes all tests including 12 hidden test cases with random seeds.

RecommendationN/A - task is fine

Trajectory

Tool-by-tool agent trajectory

30 tool calls · 2 tool types · 38 steps

I’ll inspect the existing stub and data files first, then patch the update logic and run it against the provided inputs to verify the CSV output shape and values.

shell

/bin/zsh -lc "sed -n '1,220p' main.py"

shell

/bin/zsh -lc "sed -n '1,220p' main.py"

output

# Starter stub for the toroidal Game-of-Life task.
#
# It reads the starting board from data/grid.csv and the run settings from
# data/config.json, then (for now) just copies the board straight through
# to output/next.csv WITHOUT advancing any generations. Replace the body so
# it actually evolves the board the requested number of steps under the rules
# described in the task.

import csv
import json
import os

with open("data/grid.csv") as f:
    grid = [[int(x) for x in row] for row in csv.reader(f) if row]

with open("data/config.json") as f:
    config = json.load(f)

generations = int(config["generations"])  # number of steps to advance
topology = config["topology"]

# TODO: replace this passthrough with the evolved board. As written it ignores
# the rules and the generation count, so it does not produce the requested board.
next_grid = grid

os.makedirs("output", exist_ok=True)
with open("output/next.csv", "w", newline="") as f:
    csv.writer(f).writerows(next_grid)

shell

/bin/zsh -lc "sed -n '1,20p' data/grid.csv"

shell

/bin/zsh -lc "sed -n '1,20p' data/grid.csv"

output

1,1,0,0,0,0,0,1
0,0,0,0,1,1,0,1
0,2,0,0,1,0,0,0
0,0,0,0,0,0,2,0
1,0,0,0,0,0,0,0
1,0,1,1,0,0,0,1

shell

/bin/zsh -lc "sed -n '1,80p' data/config.json"

shell

/bin/zsh -lc "sed -n '1,80p' data/config.json"

output

{"topology": "toroidal", "generations": 3}

shell

/bin/zsh -lc 'rg --files'

shell

/bin/zsh -lc 'rg --files'

output

data/grid.csv
data/config.json
main.py
task.toml
environment/README.md
instruction.md

The stub is a straight passthrough. I’m going to replace it with a small toroidal step function that treats only `1` as alive, carries `2` walls unchanged, and iterates exactly the configured generation count.

write · /var/folders/4w/8dz5qwsn6p79xjvgb6gwgs640000gn/T/eval-platform-local-7nbmbh8b/workspace/main.py

(empty file)

write · /var/folders/4w/8dz5qwsn6p79xjvgb6gwgs640000gn/T/eval-platform-local-7nbmbh8b/workspace/main.py

(empty file)

The implementation is in place. I’m running the script now and checking the generated CSV so I can catch formatting or dimension issues, not just syntax errors.

shell

/bin/zsh -lc 'python3 main.py'

shell

/bin/zsh -lc 'python3 main.py'

shell

/bin/zsh -lc 'python3 -m py_compile main.py'

shell

/bin/zsh -lc 'python3 -m py_compile main.py'

The script and bytecode check both completed cleanly. I’m doing one last read of `output/next.csv` and a quick dimension check against the input.

shell

/bin/zsh -lc "sed -n '1,40p' output/next.csv"

shell

/bin/zsh -lc "sed -n '1,40p' output/next.csv"

output

0,1,1,1,0,1,0,0
0,1,1,0,0,0,0,0
0,2,0,0,0,0,0,0
1,1,0,0,0,0,2,0
1,1,0,0,0,0,0,0
1,0,1,0,0,0,0,0

shell

/bin/zsh -lc "python3 - <<'PY'
import csv
for path in ('data/grid.csv', 'output/next.csv'):
    with open(path, newline='') as f:
        rows = list(csv.reader(f))
    print(path, len(rows), len(rows[0]) if rows else 0, sorted({value for row in rows for value in row}))
PY"

shell

/bin/zsh -lc "python3 - <<'PY'
import csv
for path in ('data/grid.csv', 'output/next.csv'):
    with open(path, newline='') as f:
        rows = list(csv.reader(f))
    print(path, len(rows), len(rows[0]) if rows else 0, sorted({value for row in rows for value in row}))
PY"

output

data/grid.csv 6 8 ['0', '1', '2']
output/next.csv 6 8 ['0', '1', '2']

The output has the same 6x8 shape and only `0`, `1`, and `2` values. I’m checking the final diff so the close-out is accurate.

shell

/bin/zsh -lc 'git diff -- main.py output/next.csv'

shell

/bin/zsh -lc 'git diff -- main.py output/next.csv'

output

diff --git a/main.py b/output/next.csv
index 3970717..a35d029 100644
--- a/main.py
+++ b/output/next.csv
@@ -1,71 +1,6 @@
-# Starter stub for the toroidal Game-of-Life task.
-#
-# It reads the starting board from data/grid.csv and the run settings from
-# data/config.json, then (for now) just copies the board straight through
-# to output/next.csv WITHOUT advancing any generations. Replace the body so
-# it actually evolves the board the requested number of steps under the rules
-# described in the task.
-
-import csv
-import json
-import os
-
-with open("data/grid.csv") as f:
-    grid = [[int(x) for x in row] for row in csv.reader(f) if row]
-
-with open("data/config.json") as f:
-    config = json.load(f)
-
-generations = int(config["generations"])  # number of steps to advance
-topology = config["topology"]
-
-if topology != "toroidal":
-    raise ValueError(f"unsupported topology: {topology!r}")
-
-
-def live_neighbour_count(board, row, col):
-    height = len(board)
-    width = len(board[0])
-    live_count = 0
-
-    for row_delta in (-1, 0, 1):
-        for col_delta in (-1, 0, 1):
-            if row_delta == 0 and col_delta == 0:
-                continue
-
-            neighbour_row = (row + row_delta) % height
-            neighbour_col = (col + col_delta) % width
-            if board[neighbour_row][neighbour_col] == 1:
-                live_count += 1
-
-    return live_count
-
-
-def advance_one_generation(board):
-    next_board = []
-
-    for row_index, row in enumerate(board):
-        next_row = []
-        for col_index, cell in enumerate(row):
-            if cell == 2:
-                next_row.append(2)
-                continue
-
-            live_count = live_neighbour_count(board, row_index, col_index)
-            if cell == 1:
-                next_row.append(1 if live_count in (2, 3) else 0)
-            else:
-                next_row.append(1 if live_count == 3 else 0)
-
-        next_board.append(next_row)
-
-    return next_board
-
… (+343 chars truncated)

One note from the diff check: this workspace does not appear to be behaving like a normal git worktree for that comparison, so I’m using direct file checks instead of relying on `git diff` here.

shell

/bin/zsh -lc 'git status --short'

shell

/bin/zsh -lc "sed -n '1,180p' main.py"

shell

/bin/zsh -lc 'git status --short'

output

fatal: not a git repository (or any of the parent directories): .git

shell

/bin/zsh -lc "sed -n '1,180p' main.py"

output

# Starter stub for the toroidal Game-of-Life task.
#
# It reads the starting board from data/grid.csv and the run settings from
# data/config.json, then (for now) just copies the board straight through
# to output/next.csv WITHOUT advancing any generations. Replace the body so
# it actually evolves the board the requested number of steps under the rules
# described in the task.

import csv
import json
import os

with open("data/grid.csv") as f:
    grid = [[int(x) for x in row] for row in csv.reader(f) if row]

with open("data/config.json") as f:
    config = json.load(f)

generations = int(config["generations"])  # number of steps to advance
topology = config["topology"]

if topology != "toroidal":
    raise ValueError(f"unsupported topology: {topology!r}")


def live_neighbour_count(board, row, col):
    height = len(board)
    width = len(board[0])
    live_count = 0

    for row_delta in (-1, 0, 1):
        for col_delta in (-1, 0, 1):
            if row_delta == 0 and col_delta == 0:
                continue

            neighbour_row = (row + row_delta) % height
            neighbour_col = (col + col_delta) % width
            if board[neighbour_row][neighbour_col] == 1:
                live_count += 1

    return live_count


def advance_one_generation(board):
    next_board = []

    for row_index, row in enumerate(board):
        next_row = []
        for col_index, cell in enumerate(row):
            if cell == 2:
                next_row.append(2)
                continue

            live_count = live_neighbour_count(board, row_index, col_index)
            if cell == 1:
                next_row.append(1 if live_count in (2, 3) else 0)
            else:
                next_row.append(1 if live_count == 3 else 0)

        next_board.append(next_row)

    return next_board


next_grid = grid
for _ in range(generations):
    next_grid = advance_one_generation(next_grid)

os.makedirs("output", exist_ok=True)
with open("output/next.csv", "w", newline="") as 
… (+42 chars truncated)

`main.py` now contains the expected toroidal evolution logic. I’m cleaning up any transient bytecode from the verification run so the workspace only keeps the requested source/output files.

shell

/bin/zsh -lc 'rg --files'

shell

/bin/zsh -lc "find . -type d -name '__pycache__' -print"

shell

/bin/zsh -lc 'rg --files'

output

data/grid.csv
data/config.json
main.py
task.toml
environment/README.md
instruction.md
__pycache__/main.cpython-312.pyc
output/next.csv

shell

/bin/zsh -lc "find . -type d -name '__pycache__' -print"

output

./__pycache__

shell

/bin/zsh -lc 'rm -rf __pycache__'

shell

/bin/zsh -lc 'rm -rf __pycache__'

Implemented the toroidal Game of Life logic in [main.py](/var/folders/4w/8dz5qwsn6p79xjvgb6gwgs640000gn/T/eval-platform-local-7nbmbh8b/workspace/main.py). It now: - Reads `data/grid.csv` and `data/config.json` - Preserves wall cells as `2` - Counts only live `1` neighbours with wrap-around indexing - Applies the update simultaneously for the configured generations - Writes the final board to [output/next.csv](/var/folders/4w/8dz5qwsn6p79xjvgb6gwgs640000gn/T/eval-platform-local-7nbmbh8b/workspace/output/next.csv) Verified with `python3 main.py` and `python3 -m py_compile main.py`; output dimensions match the input `6x8` grid.

Final diff , what the agent changed

--- a/main.py

+++ b/main.py

@@ -19,9 +19,52 @@

generations = int(config["generations"]) # number of steps to advance

topology = config["topology"]

-# TODO: replace this passthrough with the evolved board. As written it ignores

-# the rules and the generation count, so it does not produce the requested board.

+if topology != "toroidal":

+ raise ValueError(f"unsupported topology: {topology!r}")

+def live_neighbour_count(board, row, col):

+ height = len(board)

+ width = len(board[0])

+ live_count = 0

+ for row_delta in (-1, 0, 1):

+ for col_delta in (-1, 0, 1):

+ if row_delta == 0 and col_delta == 0:

+ continue

+ neighbour_row = (row + row_delta) % height

+ neighbour_col = (col + col_delta) % width

+ if board[neighbour_row][neighbour_col] == 1:

+ live_count += 1

+ return live_count

+def advance_one_generation(board):

+ next_board = []

+ for row_index, row in enumerate(board):

+ next_row = []

+ for col_index, cell in enumerate(row):

+ if cell == 2:

+ next_row.append(2)

+ continue

+ live_count = live_neighbour_count(board, row_index, col_index)

+ if cell == 1:

+ next_row.append(1 if live_count in (2, 3) else 0)

+ else:

+ next_row.append(1 if live_count == 3 else 0)

+ next_board.append(next_row)

+ return next_board

next_grid = grid

+for _ in range(generations):

+ next_grid = advance_one_generation(next_grid)

os.makedirs("output", exist_ok=True)

with open("output/next.csv", "w", newline="") as f:

--- /dev/null

+++ b/output/next.csv

@@ -0,0 +1,6 @@

+0,1,1,1,0,1,0,0

+0,1,1,0,0,0,0,0

+0,2,0,0,0,0,0,0

+1,1,0,0,0,0,2,0

+1,1,0,0,0,0,0,0

+1,0,1,0,0,0,0,0

Verifier output , the proof behind the reward

tests/test.sh

============================= test session starts ==============================
platform darwin -- Python 3.12.4, pytest-8.4.1, pluggy-1.6.0 -- /Library/Frameworks/Python.framework/Versions/3.12/bin/python3
cachedir: .pytest_cache
rootdir: <tmp>/workspace
plugins: anyio-4.12.1, respx-0.22.0, mock-3.15.1, asyncio-0.21.1
asyncio: mode=Mode.STRICT
collecting ... collected 6 items

tests/test_outputs.py::test_output_exists PASSED                         [ 16%]
tests/test_outputs.py::test_shipped_dimensions_and_values PASSED         [ 33%]
tests/test_outputs.py::test_shipped_walls_preserved PASSED               [ 50%]
tests/test_outputs.py::test_shipped_correct PASSED                       [ 66%]
tests/test_outputs.py::test_not_identity_copy PASSED                     [ 83%]
tests/test_outputs.py::test_hidden_alternates PASSED                     [100%]

============================== 6 passed in 0.28s ===============================

Reproduce this trial: git checkout 2f94510 && PYTHONPATH=src python3 scripts/build_site.py , then open trial/trial_2a7c35308b764080. Re-running the agent live requires EVAL_PLATFORM_ENABLE_OAUTH_SMOKE=1 and is non-deterministic.

Trial trial_2a7c35308b764080 · verifier authoritative; classifier explanatory.