diff --git a/diceplayer/__init__.py b/diceplayer/__init__.py
index 36e8f16..e69de29 100644
--- a/diceplayer/__init__.py
+++ b/diceplayer/__init__.py
@@ -1,3 +0,0 @@
-from diceplayer.utils.logger import RunLogger
-
-
diff --git a/diceplayer/__main__.py b/diceplayer/__main__.py
index 538be5f..762680f 100644
--- a/diceplayer/__main__.py
+++ b/diceplayer/__main__.py
@@ -1,9 +1,7 @@
-from diceplayer.config.player_config import PlayerConfig
+from diceplayer.cli import ArgsModel, read_input
 from diceplayer.logger import logger
 from diceplayer.player import Player
 
-import yaml
-
 import argparse
 from importlib import metadata
 
@@ -11,17 +9,6 @@ from importlib import metadata
 VERSION = metadata.version("diceplayer")
 
 
-def read_input(infile) -> PlayerConfig:
-    try:
-        with open(infile, "r") as f:
-            return PlayerConfig.model_validate(
-                yaml.safe_load(f)
-            )
-    except Exception as e:
-        logger.exception("Failed to read input file")
-        raise e
-
-
 def main():
     parser = argparse.ArgumentParser(prog="Diceplayer")
     parser.add_argument(
@@ -46,7 +33,7 @@ def main():
         metavar="OUTFILE",
         help="output file of diceplayer [default = run.log]",
     )
-    args = parser.parse_args()
+    args = ArgsModel.from_args(parser.parse_args())
 
     logger.set_output_file(args.outfile)
 
@@ -56,4 +43,4 @@ def main():
 
 
 if __name__ == "__main__":
-    main()
\ No newline at end of file
+    main()
diff --git a/diceplayer/cli/__init__.py b/diceplayer/cli/__init__.py
new file mode 100644
index 0000000..266597a
--- /dev/null
+++ b/diceplayer/cli/__init__.py
@@ -0,0 +1,5 @@
+from .args_model import ArgsModel
+from .read_input_file import read_input
+
+
+__all__ = ["ArgsModel", "read_input"]
diff --git a/diceplayer/cli/args_model.py b/diceplayer/cli/args_model.py
new file mode 100644
index 0000000..8c5feaa
--- /dev/null
+++ b/diceplayer/cli/args_model.py
@@ -0,0 +1,11 @@
+from pydantic import BaseModel
+
+
+class ArgsModel(BaseModel):
+    outfile: str
+    infile: str
+    continuation: bool
+
+    @classmethod
+    def from_args(cls, args):
+        return cls(**vars(args))
diff --git a/diceplayer/cli/read_input_file.py b/diceplayer/cli/read_input_file.py
new file mode 100644
index 0000000..36f8946
--- /dev/null
+++ b/diceplayer/cli/read_input_file.py
@@ -0,0 +1,13 @@
+from diceplayer.config import PlayerConfig
+from diceplayer.logger import logger
+
+import yaml
+
+
+def read_input(infile) -> PlayerConfig:
+    try:
+        with open(infile, "r") as f:
+            return PlayerConfig.model_validate(yaml.safe_load(f))
+    except Exception as e:
+        logger.exception("Failed to read input file")
+        raise e
diff --git a/diceplayer/config/__init__.py b/diceplayer/config/__init__.py
index e69de29..6d7a441 100644
--- a/diceplayer/config/__init__.py
+++ b/diceplayer/config/__init__.py
@@ -0,0 +1,10 @@
+from .dice_config import DiceConfig
+from .gaussian_config import GaussianConfig
+from .player_config import PlayerConfig
+
+
+__all__ = [
+    "DiceConfig",
+    "GaussianConfig",
+    "PlayerConfig",
+]
diff --git a/diceplayer/config/dice_config.py b/diceplayer/config/dice_config.py
index 30af670..ccfebd8 100644
--- a/diceplayer/config/dice_config.py
+++ b/diceplayer/config/dice_config.py
@@ -1,4 +1,4 @@
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, ConfigDict
 from typing_extensions import List, Literal
 
 
@@ -6,6 +6,9 @@ class DiceConfig(BaseModel):
     """
     Data Transfer Object for the Dice configuration.
     """
+    model_config = ConfigDict(
+        frozen=True,
+    )
 
     ljname: str = Field(..., description="Name of the Lennard-Jones potential file")
     outname: str = Field(
diff --git a/diceplayer/config/gaussian_config.py b/diceplayer/config/gaussian_config.py
index 9cd838f..ea2d5c2 100644
--- a/diceplayer/config/gaussian_config.py
+++ b/diceplayer/config/gaussian_config.py
@@ -1,4 +1,4 @@
-from pydantic import BaseModel, Field
+from pydantic import BaseModel, Field, ConfigDict
 from typing_extensions import Literal
 
 
@@ -6,6 +6,9 @@ class GaussianConfig(BaseModel):
     """
     Data Transfer Object for the Gaussian configuration.
     """
+    model_config = ConfigDict(
+        frozen=True,
+    )
 
     level: str = Field(..., description="Level of theory for the QM calculations")
     qmprog: Literal["g03", "g09", "g16"] = Field(
diff --git a/diceplayer/config/player_config.py b/diceplayer/config/player_config.py
index c47248c..ab7caa3 100644
--- a/diceplayer/config/player_config.py
+++ b/diceplayer/config/player_config.py
@@ -1,19 +1,23 @@
 from diceplayer.config.dice_config import DiceConfig
 from diceplayer.config.gaussian_config import GaussianConfig
 
-from pydantic import BaseModel, Field, model_validator
-from typing_extensions import Self
+from pydantic import BaseModel, Field, model_validator, ConfigDict
+from typing_extensions import Self, Any
 
 from pathlib import Path
 
 
 MIN_STEP = 20000
+STEP_INCREMENT = 1000
 
 
 class PlayerConfig(BaseModel):
     """
     Data Transfer Object for the player configuration.
     """
+    model_config = ConfigDict(
+        frozen=True,
+    )
 
     opt: bool = Field(..., description="Whether to perform geometry optimization")
     maxcyc: int = Field(
@@ -42,7 +46,9 @@ class PlayerConfig(BaseModel):
         "simfiles", description="Directory name for the simulation files"
     )
 
-    @model_validator(mode="after")
-    def validate_altsteps(self) -> Self:
-        self.altsteps = round(max(MIN_STEP, self.altsteps) / 1000) * 1000
-        return self
+    @model_validator(mode="before")
+    @staticmethod
+    def validate_altsteps(fields) -> dict[str, Any]:
+        altsteps = fields.pop("altsteps", MIN_STEP)
+        fields["altsteps"] = round(max(MIN_STEP, altsteps) / STEP_INCREMENT) * STEP_INCREMENT
+        return fields
diff --git a/diceplayer/logger.py b/diceplayer/logger.py
index 9b841c2..6bb5249 100644
--- a/diceplayer/logger.py
+++ b/diceplayer/logger.py
@@ -1,4 +1,4 @@
-from diceplayer import RunLogger
+from diceplayer.utils import RunLogger
 
 
 logger = RunLogger("diceplayer")
diff --git a/diceplayer/player.py b/diceplayer/player.py
index 6800b28..8aff1c7 100644
--- a/diceplayer/player.py
+++ b/diceplayer/player.py
@@ -5,5 +5,4 @@ class Player:
     def __init__(self, config: PlayerConfig):
         self.config = config
 
-    def play(self, continuation = False):
-        ...
\ No newline at end of file
+    def play(self, continuation=False): ...
diff --git a/diceplayer/state/__init__.py b/diceplayer/state/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/diceplayer/state/state_handler.py b/diceplayer/state/state_handler.py
new file mode 100644
index 0000000..fa456f4
--- /dev/null
+++ b/diceplayer/state/state_handler.py
@@ -0,0 +1,31 @@
+import pickle
+from pathlib import Path
+
+from diceplayer.config import PlayerConfig
+from diceplayer.environment import System
+from diceplayer.logger import logger
+from diceplayer.state.state_model import StateModel
+
+
+class StateHandler:
+    def __init__(self, sim_dir: Path, state_file: str = "state.pkl"):
+        self._state_file = sim_dir / state_file
+
+    def get_state(self, config: PlayerConfig) -> StateModel | None:
+        if not self._state_file.exists():
+            return None
+
+        with self._state_file.open(mode="r") as f:
+            data = pickle.load(f)
+
+            model = StateModel.model_validate(data)
+
+            if hash(model.config) != hash(config):
+                logger.warning("The configuration in the state file does not match the provided configuration.")
+                return None
+
+            return model
+
+    def save_state(self, state: StateModel) -> None:
+        with self._state_file.open(mode="wb") as f:
+            pickle.dump(state.model_dump(), f)
\ No newline at end of file
diff --git a/diceplayer/state/state_model.py b/diceplayer/state/state_model.py
new file mode 100644
index 0000000..7a1099f
--- /dev/null
+++ b/diceplayer/state/state_model.py
@@ -0,0 +1,10 @@
+from pydantic import BaseModel
+
+from diceplayer.config import PlayerConfig
+from diceplayer.environment import System
+
+
+class StateModel(BaseModel):
+    config: PlayerConfig
+    system: System
+    current_cycle: int
\ No newline at end of file
diff --git a/diceplayer/utils/logger.py b/diceplayer/utils/logger.py
index 51bcb8c..8c08d02 100644
--- a/diceplayer/utils/logger.py
+++ b/diceplayer/utils/logger.py
@@ -5,7 +5,7 @@ import sys
 from pathlib import Path
 
 
-H = TypeVar('H', bound=logging.Handler)
+H = TypeVar("H", bound=logging.Handler)
 
 
 class RunLogger(logging.Logger):
@@ -18,33 +18,27 @@ class RunLogger(logging.Logger):
             self._configure_handler(logging.StreamHandler(stream), level)
         )
 
-
     def set_output_file(self, outfile: Path, level=logging.INFO):
         for handler in list(self.handlers):
             if not isinstance(handler, logging.FileHandler):
                 continue
             self.handlers.remove(handler)
 
-        self.handlers.append(
-            self._create_file_handler(outfile, level)
-        )
-
-
+        self.handlers.append(self._create_file_handler(outfile, level))
 
     @staticmethod
-    def _create_file_handler(file: str|Path, level) -> logging.FileHandler:
+    def _create_file_handler(file: str | Path, level) -> logging.FileHandler:
         file = Path(file)
 
         if file.exists():
-            file.rename(file.with_suffix('.log.backup'))
+            file.rename(file.with_suffix(".log.backup"))
 
         handler = logging.FileHandler(file)
         return RunLogger._configure_handler(handler, level)
 
-
     @staticmethod
     def _configure_handler(handler: H, level) -> H:
         handler.setLevel(level)
-        formatter = logging.Formatter('%(message)s')
+        formatter = logging.Formatter("%(message)s")
         handler.setFormatter(formatter)
-        return handler
\ No newline at end of file
+        return handler
diff --git a/tests/state/__init__.py b/tests/state/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/state/test_state_handler.py b/tests/state/test_state_handler.py
new file mode 100644
index 0000000..226df9f
--- /dev/null
+++ b/tests/state/test_state_handler.py
@@ -0,0 +1,47 @@
+import tempfile
+from pathlib import Path
+
+import pytest
+
+from diceplayer.config import PlayerConfig, DiceConfig, GaussianConfig
+from diceplayer.state.state_handler import StateHandler
+
+
+class TestStateHandler:
+    @pytest.fixture
+    def player_config(self) -> PlayerConfig:
+        return PlayerConfig(
+            opt=True,
+            mem=12,
+            maxcyc=100,
+            nprocs=4,
+            ncores=4,
+            dice=DiceConfig(
+                ljname="test",
+                outname="test",
+                dens=1.0,
+                nmol=[1],
+                nstep=[1, 1],
+            ),
+            gaussian=GaussianConfig(
+                level="test",
+                qmprog="g16",
+                keywords="test",
+            ),
+        )
+
+    def test_state_handler_initialization(self):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            tmpdir_path = Path(tmpdir)
+            state_handler = StateHandler(tmpdir_path)
+
+            assert isinstance(state_handler, StateHandler)
+
+    def test_state_handler_get_state(self, player_config: PlayerConfig):
+        with tempfile.TemporaryDirectory() as tmpdir:
+            tmpdir_path = Path(tmpdir)
+            state_handler = StateHandler(tmpdir_path)
+
+            state = state_handler.get_state(player_config)
+
+            assert state is None
\ No newline at end of file