diff --git a/.gitmodules b/.gitmodules
index 588953b..93195f4 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,3 @@
 [submodule "verl"]
 	path = verl
-	url = git@github.com:Agent-One-Lab/verl.git
+	url = https://github.com/Agent-One-Lab/verl.git
diff --git a/src/agentfly/envs/chess_env.py b/src/agentfly/envs/chess_env.py
index 43341fa..3c7e9c2 100644
--- a/src/agentfly/envs/chess_env.py
+++ b/src/agentfly/envs/chess_env.py
@@ -5,6 +5,7 @@
 """
 
 import asyncio
+import shutil
 from typing import Any, Dict, List, Optional, Tuple, Union
 
 import chess
@@ -13,6 +14,26 @@
 from .env_base import BaseEnv
 
 
+def _find_stockfish() -> str:
+    """Find the Stockfish binary on the system."""
+    # Check common paths
+    common_paths = [
+        "/usr/games/stockfish",           # Ubuntu/Debian
+        "/usr/bin/stockfish",             # Linux
+        "/opt/homebrew/bin/stockfish",    # macOS (Homebrew ARM)
+        "/usr/local/bin/stockfish",       # macOS (Homebrew Intel)
+    ]
+    for path in common_paths:
+        if shutil.which(path) or __import__('os').path.isfile(path):
+            return path
+    # Try to find in PATH
+    path = shutil.which("stockfish")
+    if path:
+        return path
+    # Default fallback
+    return "/opt/homebrew/bin/stockfish"
+
+
 class ChessPuzzleEnv(BaseEnv):
     """
     Chess puzzle environment using python-chess and Stockfish.
@@ -49,7 +70,7 @@ class ChessPuzzleEnv(BaseEnv):
 
     def __init__(
         self,
-        stockfish_path: str = "/opt/homebrew/bin/stockfish",
+        stockfish_path: str = None,
         analysis_time: float = 0.1,
         analysis_depth: int = 20,
         max_moves: int = 20,
@@ -58,7 +79,7 @@ def __init__(
         Initialize the chess puzzle environment.
 
         Args:
-            stockfish_path: Path to the Stockfish binary. Common paths:
+            stockfish_path: Path to the Stockfish binary. If None, auto-detects. Common paths:
                 - macOS (Homebrew): /opt/homebrew/bin/stockfish
                 - Linux: /usr/bin/stockfish or /usr/games/stockfish
                 - Windows: C:\\path\\to\\stockfish.exe
@@ -67,7 +88,7 @@ def __init__(
             max_moves: Maximum number of moves allowed per puzzle
         """
         super().__init__()
-        self.stockfish_path = stockfish_path
+        self.stockfish_path = stockfish_path or _find_stockfish()
         self.analysis_time = analysis_time
         self.analysis_depth = analysis_depth
         self.max_moves = max_moves
diff --git a/tests/unit/envs/test_chess_env.py b/tests/unit/envs/test_chess_env.py
index 33132f2..0c202af 100644
--- a/tests/unit/envs/test_chess_env.py
+++ b/tests/unit/envs/test_chess_env.py
@@ -7,6 +7,7 @@
 """
 
 import pytest
+import pytest_asyncio
 from agentfly.envs.chess_env import ChessPuzzleEnv
 
 
@@ -17,7 +18,7 @@
 )
 
 
-@pytest.fixture
+@pytest_asyncio.fixture
 async def chess_env():
     """Create and start a chess environment for testing."""
     env = ChessPuzzleEnv()
@@ -171,7 +172,7 @@ async def test_puzzle_state_tracking(chess_env):
     puzzle = {
         "puzzle_id": "test",
         "fen": "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1",
-        "moves": "e2e4 e7e5 g1f3"  # Multi-move puzzle
+        "moves": "e2e4 e7e5 g1f3"  # Multi-move puzzle: e2e4 is setup, e7e5 is agent's move, g1f3 is response
     }
 
     await chess_env.reset(puzzle)
@@ -183,11 +184,11 @@ async def test_puzzle_state_tracking(chess_env):
     # After setup, solution index should be 1 (first move was played)
     assert chess_env._current_solution_idx == 1
 
-    # Make the correct move
-    await chess_env.step("e2e4")
+    # Make the correct move (e7e5, not e2e4 which was already auto-played as setup)
+    await chess_env.step("e7e5")
 
     assert len(chess_env.moves_made) == 1
-    assert "e2e4" in chess_env.moves_made
+    assert "e7e5" in chess_env.moves_made
 
 
 @pytest.mark.asyncio