diff --git a/.gitignore b/.gitignore
index 653fd83..bd23c42 100644
--- a/.gitignore
+++ b/.gitignore
@@ -178,3 +178,4 @@ data/
 
 # Workspace
 workspace/
+.DS_Store
diff --git a/app/config.py b/app/config.py
index 2275fb4..f1968d2 100644
--- a/app/config.py
+++ b/app/config.py
@@ -23,8 +23,23 @@ class LLMSettings(BaseModel):
     temperature: float = Field(1.0, description="Sampling temperature")
 
 
+class SandboxConfig(BaseModel):
+    """Configuration for the execution sandbox"""
+
+    use_sandbox: bool = Field(False, description="Whether to use the sandbox")
+    image: str = Field("python:3.10-slim", description="Base image")
+    work_dir: str = Field("/workspace", description="Container working directory")
+    memory_limit: str = Field("512m", description="Memory limit")
+    cpu_limit: float = Field(1.0, description="CPU limit")
+    timeout: int = Field(300, description="Default command timeout (seconds)")
+    network_enabled: bool = Field(
+        False, description="Whether network access is allowed"
+    )
+
+
 class AppConfig(BaseModel):
     llm: Dict[str, LLMSettings]
+    sandbox: SandboxConfig
 
 
 class Config:
@@ -85,7 +100,8 @@ class Config:
                     name: {**default_settings, **override_config}
                     for name, override_config in llm_overrides.items()
                 },
-            }
+            },
+            "sandbox": raw_config.get("sandbox", {}),
         }
 
         self._config = AppConfig(**config_dict)
@@ -94,5 +110,9 @@ class Config:
     def llm(self) -> Dict[str, LLMSettings]:
         return self._config.llm
 
+    @property
+    def sandbox(self) -> SandboxConfig:
+        return self._config.sandbox
+
 
 config = Config()
diff --git a/app/sandbox/__init__.py b/app/sandbox/__init__.py
new file mode 100644
index 0000000..ccf0df6
--- /dev/null
+++ b/app/sandbox/__init__.py
@@ -0,0 +1,30 @@
+"""
+Docker Sandbox Module
+
+Provides secure containerized execution environment with resource limits
+and isolation for running untrusted code.
+"""
+from app.sandbox.client import (
+    BaseSandboxClient,
+    LocalSandboxClient,
+    create_sandbox_client,
+)
+from app.sandbox.core.exceptions import (
+    SandboxError,
+    SandboxResourceError,
+    SandboxTimeoutError,
+)
+from app.sandbox.core.manager import SandboxManager
+from app.sandbox.core.sandbox import DockerSandbox
+
+
+__all__ = [
+    "DockerSandbox",
+    "SandboxManager",
+    "BaseSandboxClient",
+    "LocalSandboxClient",
+    "create_sandbox_client",
+    "SandboxError",
+    "SandboxTimeoutError",
+    "SandboxResourceError",
+]
diff --git a/app/sandbox/client.py b/app/sandbox/client.py
new file mode 100644
index 0000000..e2c412f
--- /dev/null
+++ b/app/sandbox/client.py
@@ -0,0 +1,201 @@
+from abc import ABC, abstractmethod
+from typing import Dict, Optional, Protocol
+
+from app.config import SandboxConfig
+from app.sandbox.core.sandbox import DockerSandbox
+
+
+class SandboxFileOperations(Protocol):
+    """Protocol for sandbox file operations."""
+
+    async def copy_from(self, container_path: str, local_path: str) -> None:
+        """Copies file from container to local.
+
+        Args:
+            container_path: File path in container.
+            local_path: Local destination path.
+        """
+        ...
+
+    async def copy_to(self, local_path: str, container_path: str) -> None:
+        """Copies file from local to container.
+
+        Args:
+            local_path: Local source file path.
+            container_path: Destination path in container.
+        """
+        ...
+
+    async def read_file(self, path: str) -> str:
+        """Reads file content from container.
+
+        Args:
+            path: File path in container.
+
+        Returns:
+            str: File content.
+        """
+        ...
+
+    async def write_file(self, path: str, content: str) -> None:
+        """Writes content to file in container.
+
+        Args:
+            path: File path in container.
+            content: Content to write.
+        """
+        ...
+
+
+class BaseSandboxClient(ABC):
+    """Base sandbox client interface."""
+
+    @abstractmethod
+    async def create(
+        self,
+        config: Optional[SandboxConfig] = None,
+        volume_bindings: Optional[Dict[str, str]] = None,
+    ) -> None:
+        """Creates sandbox."""
+
+    @abstractmethod
+    async def run_command(self, command: str, timeout: Optional[int] = None) -> str:
+        """Executes command."""
+
+    @abstractmethod
+    async def copy_from(self, container_path: str, local_path: str) -> None:
+        """Copies file from container."""
+
+    @abstractmethod
+    async def copy_to(self, local_path: str, container_path: str) -> None:
+        """Copies file to container."""
+
+    @abstractmethod
+    async def read_file(self, path: str) -> str:
+        """Reads file."""
+
+    @abstractmethod
+    async def write_file(self, path: str, content: str) -> None:
+        """Writes file."""
+
+    @abstractmethod
+    async def cleanup(self) -> None:
+        """Cleans up resources."""
+
+
+class LocalSandboxClient(BaseSandboxClient):
+    """Local sandbox client implementation."""
+
+    def __init__(self):
+        """Initializes local sandbox client."""
+        self.sandbox: Optional[DockerSandbox] = None
+
+    async def create(
+        self,
+        config: Optional[SandboxConfig] = None,
+        volume_bindings: Optional[Dict[str, str]] = None,
+    ) -> None:
+        """Creates a sandbox.
+
+        Args:
+            config: Sandbox configuration.
+            volume_bindings: Volume mappings.
+
+        Raises:
+            RuntimeError: If sandbox creation fails.
+        """
+        self.sandbox = DockerSandbox(config, volume_bindings)
+        await self.sandbox.create()
+
+    async def run_command(self, command: str, timeout: Optional[int] = None) -> str:
+        """Runs command in sandbox.
+
+        Args:
+            command: Command to execute.
+            timeout: Execution timeout in seconds.
+
+        Returns:
+            Command output.
+
+        Raises:
+            RuntimeError: If sandbox not initialized.
+        """
+        if not self.sandbox:
+            raise RuntimeError("Sandbox not initialized")
+        return await self.sandbox.run_command(command, timeout)
+
+    async def copy_from(self, container_path: str, local_path: str) -> None:
+        """Copies file from container to local.
+
+        Args:
+            container_path: File path in container.
+            local_path: Local destination path.
+
+        Raises:
+            RuntimeError: If sandbox not initialized.
+        """
+        if not self.sandbox:
+            raise RuntimeError("Sandbox not initialized")
+        await self.sandbox.copy_from(container_path, local_path)
+
+    async def copy_to(self, local_path: str, container_path: str) -> None:
+        """Copies file from local to container.
+
+        Args:
+            local_path: Local source file path.
+            container_path: Destination path in container.
+
+        Raises:
+            RuntimeError: If sandbox not initialized.
+        """
+        if not self.sandbox:
+            raise RuntimeError("Sandbox not initialized")
+        await self.sandbox.copy_to(local_path, container_path)
+
+    async def read_file(self, path: str) -> str:
+        """Reads file from container.
+
+        Args:
+            path: File path in container.
+
+        Returns:
+            File content.
+
+        Raises:
+            RuntimeError: If sandbox not initialized.
+        """
+        if not self.sandbox:
+            raise RuntimeError("Sandbox not initialized")
+        return await self.sandbox.read_file(path)
+
+    async def write_file(self, path: str, content: str) -> None:
+        """Writes file to container.
+
+        Args:
+            path: File path in container.
+            content: File content.
+
+        Raises:
+            RuntimeError: If sandbox not initialized.
+        """
+        if not self.sandbox:
+            raise RuntimeError("Sandbox not initialized")
+        await self.sandbox.write_file(path, content)
+
+    async def cleanup(self) -> None:
+        """Cleans up resources."""
+        if self.sandbox:
+            await self.sandbox.cleanup()
+            self.sandbox = None
+
+
+async def create_sandbox_client() -> LocalSandboxClient:
+    """Creates a sandbox client.
+
+    Returns:
+        LocalSandboxClient: Sandbox client instance.
+    """
+    return LocalSandboxClient()
+
+
+SANDBOX_CLIENT = create_sandbox_client()
diff --git a/app/sandbox/core/exceptions.py b/app/sandbox/core/exceptions.py
new file mode 100644
index 0000000..5c1f0e8
--- /dev/null
+++ b/app/sandbox/core/exceptions.py
@@ -0,0 +1,17 @@
+"""Exception classes for the sandbox system.
+
+This module defines custom exceptions used throughout the sandbox system to
+handle various error conditions in a structured way.
+"""
+
+
+class SandboxError(Exception):
+    """Base exception for sandbox-related errors."""
+
+
+class SandboxTimeoutError(SandboxError):
+    """Exception raised when a sandbox operation times out."""
+
+
+class SandboxResourceError(SandboxError):
+    """Exception raised for resource-related errors."""
diff --git a/app/sandbox/core/manager.py b/app/sandbox/core/manager.py
new file mode 100644
index 0000000..6269d72
--- /dev/null
+++ b/app/sandbox/core/manager.py
@@ -0,0 +1,313 @@
+import asyncio
+import uuid
+from contextlib import asynccontextmanager
+from typing import Dict, Optional, Set
+
+import docker
+from docker.errors import APIError, ImageNotFound
+
+from app.config import SandboxConfig
+from app.logger import logger
+from app.sandbox.core.sandbox import DockerSandbox
+
+
+class SandboxManager:
+    """Docker sandbox manager.
+
+    Manages multiple DockerSandbox instances lifecycle including creation,
+    monitoring, and cleanup. Provides concurrent access control and automatic
+    cleanup mechanisms for sandbox resources.
+
+    Attributes:
+        max_sandboxes: Maximum allowed number of sandboxes.
+        idle_timeout: Sandbox idle timeout in seconds.
+        cleanup_interval: Cleanup check interval in seconds.
+        _sandboxes: Active sandbox instance mapping.
+        _last_used: Last used time record for sandboxes.
+    """
+
+    def __init__(
+        self,
+        max_sandboxes: int = 100,
+        idle_timeout: int = 3600,
+        cleanup_interval: int = 300,
+    ):
+        """Initializes sandbox manager.
+
+        Args:
+            max_sandboxes: Maximum sandbox count limit.
+            idle_timeout: Idle timeout in seconds.
+            cleanup_interval: Cleanup check interval in seconds.
+        """
+        self.max_sandboxes = max_sandboxes
+        self.idle_timeout = idle_timeout
+        self.cleanup_interval = cleanup_interval
+
+        # Docker client
+        self._client = docker.from_env()
+
+        # Resource mappings
+        self._sandboxes: Dict[str, DockerSandbox] = {}
+        self._last_used: Dict[str, float] = {}
+
+        # Concurrency control
+        self._locks: Dict[str, asyncio.Lock] = {}
+        self._global_lock = asyncio.Lock()
+        self._active_operations: Set[str] = set()
+
+        # Cleanup task
+        self._cleanup_task: Optional[asyncio.Task] = None
+        self._is_shutting_down = False
+
+        # Start automatic cleanup
+        self.start_cleanup_task()
+
+    async def ensure_image(self, image: str) -> bool:
+        """Ensures Docker image is available.
+
+        Args:
+            image: Image name.
+
+        Returns:
+            bool: Whether image is available.
+        """
+        try:
+            self._client.images.get(image)
+            return True
+        except ImageNotFound:
+            try:
+                logger.info(f"Pulling image {image}...")
+                await asyncio.get_event_loop().run_in_executor(
+                    None, self._client.images.pull, image
+                )
+                return True
+            except (APIError, Exception) as e:
+                logger.error(f"Failed to pull image {image}: {e}")
+                return False
+
+    @asynccontextmanager
+    async def sandbox_operation(self, sandbox_id: str):
+        """Context manager for sandbox operations.
+
+        Provides concurrency control and usage time updates.
+
+        Args:
+            sandbox_id: Sandbox ID.
+
+        Raises:
+            KeyError: If sandbox not found.
+        """
+        if sandbox_id not in self._locks:
+            self._locks[sandbox_id] = asyncio.Lock()
+
+        async with self._locks[sandbox_id]:
+            if sandbox_id not in self._sandboxes:
+                raise KeyError(f"Sandbox {sandbox_id} not found")
+
+            self._active_operations.add(sandbox_id)
+            try:
+                self._last_used[sandbox_id] = asyncio.get_event_loop().time()
+                yield self._sandboxes[sandbox_id]
+            finally:
+                self._active_operations.remove(sandbox_id)
+
+    async def create_sandbox(
+        self,
+        config: Optional[SandboxConfig] = None,
+        volume_bindings: Optional[Dict[str, str]] = None,
+    ) -> str:
+        """Creates a new sandbox instance.
+
+        Args:
+            config: Sandbox configuration.
+            volume_bindings: Volume mapping configuration.
+
+        Returns:
+            str: Sandbox ID.
+
+        Raises:
+            RuntimeError: If max sandbox count reached or creation fails.
+        """
+        async with self._global_lock:
+            if len(self._sandboxes) >= self.max_sandboxes:
+                raise RuntimeError(
+                    f"Maximum number of sandboxes ({self.max_sandboxes}) reached"
+                )
+
+            config = config or SandboxConfig()
+            if not await self.ensure_image(config.image):
+                raise RuntimeError(f"Failed to ensure Docker image: {config.image}")
+
+            sandbox_id = str(uuid.uuid4())
+            try:
+                sandbox = DockerSandbox(config, volume_bindings)
+                await sandbox.create()
+
+                self._sandboxes[sandbox_id] = sandbox
+                self._last_used[sandbox_id] = asyncio.get_event_loop().time()
+                self._locks[sandbox_id] = asyncio.Lock()
+
+                logger.info(f"Created sandbox {sandbox_id}")
+                return sandbox_id
+
+            except Exception as e:
+                logger.error(f"Failed to create sandbox: {e}")
+                if sandbox_id in self._sandboxes:
+                    await self.delete_sandbox(sandbox_id)
+                raise RuntimeError(f"Failed to create sandbox: {e}")
+
+    async def get_sandbox(self, sandbox_id: str) -> DockerSandbox:
+        """Gets a sandbox instance.
+
+        Args:
+            sandbox_id: Sandbox ID.
+
+        Returns:
+            DockerSandbox: Sandbox instance.
+
+        Raises:
+            KeyError: If sandbox does not exist.
+        """
+        async with self.sandbox_operation(sandbox_id) as sandbox:
+            return sandbox
+
+    def start_cleanup_task(self) -> None:
+        """Starts automatic cleanup task."""
+
+        async def cleanup_loop():
+            while not self._is_shutting_down:
+                try:
+                    await self._cleanup_idle_sandboxes()
+                except Exception as e:
+                    logger.error(f"Error in cleanup loop: {e}")
+                await asyncio.sleep(self.cleanup_interval)
+
+        self._cleanup_task = asyncio.create_task(cleanup_loop())
+
+    async def _cleanup_idle_sandboxes(self) -> None:
+        """Cleans up idle sandboxes."""
+        current_time = asyncio.get_event_loop().time()
+        to_cleanup = []
+
+        async with self._global_lock:
+            for sandbox_id, last_used in self._last_used.items():
+                if (
+                    sandbox_id not in self._active_operations
+                    and current_time - last_used > self.idle_timeout
+                ):
+                    to_cleanup.append(sandbox_id)
+
+        for sandbox_id in to_cleanup:
+            try:
+                await self.delete_sandbox(sandbox_id)
+            except Exception as e:
+                logger.error(f"Error cleaning up sandbox {sandbox_id}: {e}")
+
+    async def cleanup(self) -> None:
+        """Cleans up all resources."""
+        logger.info("Starting manager cleanup...")
+        self._is_shutting_down = True
+
+        # Cancel cleanup task
+        if self._cleanup_task:
+            self._cleanup_task.cancel()
+            try:
+                await asyncio.wait_for(self._cleanup_task, timeout=1.0)
+            except (asyncio.CancelledError, asyncio.TimeoutError):
+                pass
+
+        # Get all sandbox IDs to clean up
+        async with self._global_lock:
+            sandbox_ids = list(self._sandboxes.keys())
+
+        # Concurrently clean up all sandboxes
+        cleanup_tasks = []
+        for sandbox_id in sandbox_ids:
+            task = asyncio.create_task(self._safe_delete_sandbox(sandbox_id))
+            cleanup_tasks.append(task)
+
+        if cleanup_tasks:
+            # Wait for all cleanup tasks to complete, with timeout to avoid infinite waiting
+            try:
+                await asyncio.wait(cleanup_tasks, timeout=30.0)
+            except asyncio.TimeoutError:
+                logger.error("Sandbox cleanup timed out")
+
+        # Clean up remaining references
+        self._sandboxes.clear()
+        self._last_used.clear()
+        self._locks.clear()
+        self._active_operations.clear()
+
+        logger.info("Manager cleanup completed")
+
+    async def _safe_delete_sandbox(self, sandbox_id: str) -> None:
+        """Safely deletes a single sandbox.
+
+        Args:
+            sandbox_id: Sandbox ID to delete.
+        """
+        try:
+            if sandbox_id in self._active_operations:
+                logger.warning(
+                    f"Sandbox {sandbox_id} has active operations, waiting for completion"
+                )
+                for _ in range(10):  # Wait at most 10 times
+                    await asyncio.sleep(0.5)
+                    if sandbox_id not in self._active_operations:
+                        break
+                else:
+                    logger.warning(
+                        f"Timeout waiting for sandbox {sandbox_id} operations to complete"
+                    )
+
+            # Get reference to sandbox object
+            sandbox = self._sandboxes.get(sandbox_id)
+            if sandbox:
+                await sandbox.cleanup()
+
+                # Remove sandbox record from manager
+                async with self._global_lock:
+                    self._sandboxes.pop(sandbox_id, None)
+                    self._last_used.pop(sandbox_id, None)
+                    self._locks.pop(sandbox_id, None)
+                    logger.info(f"Deleted sandbox {sandbox_id}")
+        except Exception as e:
+            logger.error(f"Error during cleanup of sandbox {sandbox_id}: {e}")
+
+    async def delete_sandbox(self, sandbox_id: str) -> None:
+        """Deletes specified sandbox.
+
+        Args:
+            sandbox_id: Sandbox ID.
+        """
+        if sandbox_id not in self._sandboxes:
+            return
+
+        try:
+            await self._safe_delete_sandbox(sandbox_id)
+        except Exception as e:
+            logger.error(f"Failed to delete sandbox {sandbox_id}: {e}")
+
+    async def __aenter__(self) -> "SandboxManager":
+        """Async context manager entry."""
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb) -> None:
+        """Async context manager exit."""
+        await self.cleanup()
+
+    def get_stats(self) -> Dict:
+        """Gets manager statistics.
+
+        Returns:
+            Dict: Statistics information.
+        """
+        return {
+            "total_sandboxes": len(self._sandboxes),
+            "active_operations": len(self._active_operations),
+            "max_sandboxes": self.max_sandboxes,
+            "idle_timeout": self.idle_timeout,
+            "cleanup_interval": self.cleanup_interval,
+            "is_shutting_down": self._is_shutting_down,
+        }
diff --git a/app/sandbox/core/sandbox.py b/app/sandbox/core/sandbox.py
new file mode 100644
index 0000000..400b12a
--- /dev/null
+++ b/app/sandbox/core/sandbox.py
@@ -0,0 +1,462 @@
+import asyncio
+import io
+import os
+import tarfile
+import tempfile
+import uuid
+from typing import Dict, Optional
+
+import docker
+from docker.errors import NotFound
+from docker.models.containers import Container
+
+from app.config import SandboxConfig
+from app.sandbox.core.exceptions import SandboxTimeoutError
+from app.sandbox.core.terminal import AsyncDockerizedTerminal
+
+
+class DockerSandbox:
+    """Docker sandbox environment.
+
+    Provides a containerized execution environment with resource limits,
+    file operations, and command execution capabilities.
+
+    Attributes:
+        config: Sandbox configuration.
+        volume_bindings: Volume mapping configuration.
+        client: Docker client.
+        container: Docker container instance.
+        terminal: Container terminal interface.
+    """
+
+    def __init__(
+        self,
+        config: Optional[SandboxConfig] = None,
+        volume_bindings: Optional[Dict[str, str]] = None,
+    ):
+        """Initializes a sandbox instance.
+
+        Args:
+            config: Sandbox configuration. Default configuration used if None.
+            volume_bindings: Volume mappings in {host_path: container_path} format.
+        """
+        self.config = config or SandboxConfig()
+        self.volume_bindings = volume_bindings or {}
+        self.client = docker.from_env()
+        self.container: Optional[Container] = None
+        self.terminal: Optional[AsyncDockerizedTerminal] = None
+
+    async def create(self) -> "DockerSandbox":
+        """Creates and starts the sandbox container.
+
+        Returns:
+            Current sandbox instance.
+
+        Raises:
+            docker.errors.APIError: If Docker API call fails.
+            RuntimeError: If container creation or startup fails.
+        """
+        try:
+            # Prepare container config
+            host_config = self.client.api.create_host_config(
+                mem_limit=self.config.memory_limit,
+                cpu_period=100000,
+                cpu_quota=int(100000 * self.config.cpu_limit),
+                network_mode="none" if not self.config.network_enabled else "bridge",
+                binds=self._prepare_volume_bindings(),
+            )
+
+            # Generate unique container name with sandbox_ prefix
+            container_name = f"sandbox_{uuid.uuid4().hex[:8]}"
+
+            # Create container
+            container = await asyncio.to_thread(
+                self.client.api.create_container,
+                image=self.config.image,
+                command="tail -f /dev/null",
+                hostname="sandbox",
+                working_dir=self.config.work_dir,
+                host_config=host_config,
+                name=container_name,
+                tty=True,
+                detach=True,
+            )
+
+            self.container = self.client.containers.get(container["Id"])
+
+            # Start container
+            await asyncio.to_thread(self.container.start)
+
+            # Initialize terminal
+            self.terminal = AsyncDockerizedTerminal(
+                container["Id"],
+                self.config.work_dir,
+                env_vars={"PYTHONUNBUFFERED": "1"}
+                # Ensure Python output is not buffered
+            )
+            await self.terminal.init()
+
+            return self
+
+        except Exception as e:
+            await self.cleanup()  # Ensure resources are cleaned up
+            raise RuntimeError(f"Failed to create sandbox: {e}") from e
+
+    def _prepare_volume_bindings(self) -> Dict[str, Dict[str, str]]:
+        """Prepares volume binding configuration.
+
+        Returns:
+            Volume binding configuration dictionary.
+        """
+        bindings = {}
+
+        # Create and add working directory mapping
+        work_dir = self._ensure_host_dir(self.config.work_dir)
+        bindings[work_dir] = {"bind": self.config.work_dir, "mode": "rw"}
+
+        # Add custom volume bindings
+        for host_path, container_path in self.volume_bindings.items():
+            bindings[host_path] = {"bind": container_path, "mode": "rw"}
+
+        return bindings
+
+    @staticmethod
+    def _ensure_host_dir(path: str) -> str:
+        """Ensures directory exists on the host.
+
+        Args:
+            path: Directory path.
+
+        Returns:
+            Actual path on the host.
+        """
+        host_path = os.path.join(
+            tempfile.gettempdir(),
+            f"sandbox_{os.path.basename(path)}_{os.urandom(4).hex()}",
+        )
+        os.makedirs(host_path, exist_ok=True)
+        return host_path
+
+    async def run_command(self, cmd: str, timeout: Optional[int] = None) -> str:
+        """Runs a command in the sandbox.
+
+        Args:
+            cmd: Command to execute.
+            timeout: Timeout in seconds.
+
+        Returns:
+            Command output as string.
+
+        Raises:
+            RuntimeError: If sandbox not initialized or command execution fails.
+            TimeoutError: If command execution times out.
+        """
+        if not self.terminal:
+            raise RuntimeError("Sandbox not initialized")
+
+        try:
+            return await self.terminal.run_command(
+                cmd, timeout=timeout or self.config.timeout
+            )
+        except TimeoutError:
+            raise SandboxTimeoutError(
+                f"Command execution timed out after {timeout or self.config.timeout} seconds"
+            )
+
+    async def read_file(self, path: str) -> str:
+        """Reads a file from the container.
+
+        Args:
+            path: File path.
+
+        Returns:
+            File contents as string.
+
+        Raises:
+            FileNotFoundError: If file does not exist.
+            RuntimeError: If read operation fails.
+        """
+        if not self.container:
+            raise RuntimeError("Sandbox not initialized")
+
+        try:
+            # Get file archive
+            resolved_path = self._safe_resolve_path(path)
+            tar_stream, _ = await asyncio.to_thread(
+                self.container.get_archive, resolved_path
+            )
+
+            # Read file content from tar stream
+            content = await self._read_from_tar(tar_stream)
+            return content.decode("utf-8")
+
+        except NotFound:
+            raise FileNotFoundError(f"File not found: {path}")
+        except Exception as e:
+            raise RuntimeError(f"Failed to read file: {e}")
+
+    async def write_file(self, path: str, content: str) -> None:
+        """Writes content to a file in the container.
+
+        Args:
+            path: Target path.
+            content: File content.
+
+        Raises:
+            RuntimeError: If write operation fails.
+        """
+        if not self.container:
+            raise RuntimeError("Sandbox not initialized")
+
+        try:
+            resolved_path = self._safe_resolve_path(path)
+            parent_dir = os.path.dirname(resolved_path)
+
+            # Create parent directory
+            if parent_dir:
+                await self.run_command(f"mkdir -p {parent_dir}")
+
+            # Prepare file data
+            tar_stream = await self._create_tar_stream(
+                os.path.basename(path), content.encode("utf-8")
+            )
+
+            # Write file
+            await asyncio.to_thread(
+                self.container.put_archive, parent_dir or "/", tar_stream
+            )
+
+        except Exception as e:
+            raise RuntimeError(f"Failed to write file: {e}")
+
+    def _safe_resolve_path(self, path: str) -> str:
+        """Safely resolves container path, preventing path traversal.
+
+        Args:
+            path: Original path.
+
+        Returns:
+            Resolved absolute path.
+
+        Raises:
+            ValueError: If path contains potentially unsafe patterns.
+        """
+        # Check for path traversal attempts
+        if ".." in path.split("/"):
+            raise ValueError("Path contains potentially unsafe patterns")
+
+        resolved = (
+            os.path.join(self.config.work_dir, path)
+            if not os.path.isabs(path)
+            else path
+        )
+        return resolved
+
+    async def copy_from(self, src_path: str, dst_path: str) -> None:
+        """Copies a file from the container.
+
+        Args:
+            src_path: Source file path (container).
+            dst_path: Destination path (host).
+
+        Raises:
+            FileNotFoundError: If source file does not exist.
+            RuntimeError: If copy operation fails.
+        """
+        try:
+            # Ensure destination file's parent directory exists
+            parent_dir = os.path.dirname(dst_path)
+            if parent_dir:
+                os.makedirs(parent_dir, exist_ok=True)
+
+            # Get file stream
+            resolved_src = self._safe_resolve_path(src_path)
+            stream, stat = await asyncio.to_thread(
+                self.container.get_archive, resolved_src
+            )
+
+            # Create temporary directory to extract file
+            with tempfile.TemporaryDirectory() as tmp_dir:
+                # Write stream to temporary file
+                tar_path = os.path.join(tmp_dir, "temp.tar")
+                with open(tar_path, "wb") as f:
+                    for chunk in stream:
+                        f.write(chunk)
+
+                # Extract file
+                with tarfile.open(tar_path) as tar:
+                    members = tar.getmembers()
+                    if not members:
+                        raise FileNotFoundError(f"Source file is empty: {src_path}")
+
+                    # If destination is a directory, we should preserve relative path structure
+                    if os.path.isdir(dst_path):
+                        tar.extractall(dst_path)
+                    else:
+                        # If destination is a file, we only extract the source file's content
+                        if len(members) > 1:
+                            raise RuntimeError(
+                                f"Source path is a directory but destination is a file: {src_path}"
+                            )
+
+                        with open(dst_path, "wb") as dst:
+                            src_file = tar.extractfile(members[0])
+                            if src_file is None:
+                                raise RuntimeError(
+                                    f"Failed to extract file: {src_path}"
+                                )
+                            dst.write(src_file.read())
+
+        except docker.errors.NotFound:
+            raise FileNotFoundError(f"Source file not found: {src_path}")
+        except Exception as e:
+            raise RuntimeError(f"Failed to copy file: {e}")
+
+    async def copy_to(self, src_path: str, dst_path: str) -> None:
+        """Copies a file to the container.
+
+        Args:
+            src_path: Source file path (host).
+            dst_path: Destination path (container).
+
+        Raises:
+            FileNotFoundError: If source file does not exist.
+            RuntimeError: If copy operation fails.
+        """
+        try:
+            if not os.path.exists(src_path):
+                raise FileNotFoundError(f"Source file not found: {src_path}")
+
+            # Create destination directory in container
+            resolved_dst = self._safe_resolve_path(dst_path)
+            container_dir = os.path.dirname(resolved_dst)
+            if container_dir:
+                await self.run_command(f"mkdir -p {container_dir}")
+
+            # Create tar file to upload
+            with tempfile.TemporaryDirectory() as tmp_dir:
+                tar_path = os.path.join(tmp_dir, "temp.tar")
+                with tarfile.open(tar_path, "w") as tar:
+                    # Handle directory source path
+                    if os.path.isdir(src_path):
+                        os.path.basename(src_path.rstrip("/"))
+                        for root, _, files in os.walk(src_path):
+                            for file in files:
+                                file_path = os.path.join(root, file)
+                                arcname = os.path.join(
+                                    os.path.basename(dst_path),
+                                    os.path.relpath(file_path, src_path),
+                                )
+                                tar.add(file_path, arcname=arcname)
+                    else:
+                        # Add single file to tar
+                        tar.add(src_path, arcname=os.path.basename(dst_path))
+
+                # Read tar file content
+                with open(tar_path, "rb") as f:
+                    data = f.read()
+
+                # Upload to container
+                await asyncio.to_thread(
+                    self.container.put_archive,
+                    os.path.dirname(resolved_dst) or "/",
+                    data,
+                )
+
+                # Verify file was created successfully
+                try:
+                    await self.run_command(f"test -e {resolved_dst}")
+                except Exception:
+                    raise RuntimeError(f"Failed to verify file creation: {dst_path}")
+
+        except FileNotFoundError:
+            raise
+        except Exception as e:
+            raise RuntimeError(f"Failed to copy file: {e}")
+
+    @staticmethod
+    async def _create_tar_stream(name: str, content: bytes) -> io.BytesIO:
+        """Creates a tar file stream.
+
+        Args:
+            name: Filename.
+            content: File content.
+
+        Returns:
+            Tar file stream.
+        """
+        tar_stream = io.BytesIO()
+        with tarfile.open(fileobj=tar_stream, mode="w") as tar:
+            tarinfo = tarfile.TarInfo(name=name)
+            tarinfo.size = len(content)
+            tar.addfile(tarinfo, io.BytesIO(content))
+        tar_stream.seek(0)
+        return tar_stream
+
+    @staticmethod
+    async def _read_from_tar(tar_stream) -> bytes:
+        """Reads file content from a tar stream.
+
+        Args:
+            tar_stream: Tar file stream.
+
+        Returns:
+            File content.
+
+        Raises:
+            RuntimeError: If read operation fails.
+        """
+        with tempfile.NamedTemporaryFile() as tmp:
+            for chunk in tar_stream:
+                tmp.write(chunk)
+            tmp.seek(0)
+
+            with tarfile.open(fileobj=tmp) as tar:
+                member = tar.next()
+                if not member:
+                    raise RuntimeError("Empty tar archive")
+
+                file_content = tar.extractfile(member)
+                if not file_content:
+                    raise RuntimeError("Failed to extract file content")
+
+                return file_content.read()
+
+    async def cleanup(self) -> None:
+        """Cleans up sandbox resources."""
+        errors = []
+        try:
+            if self.terminal:
+                try:
+                    await self.terminal.close()
+                except Exception as e:
+                    errors.append(f"Terminal cleanup error: {e}")
+                finally:
+                    self.terminal = None
+
+            if self.container:
+                try:
+                    await asyncio.to_thread(self.container.stop, timeout=5)
+                except Exception as e:
+                    errors.append(f"Container stop error: {e}")
+
+                try:
+                    await asyncio.to_thread(self.container.remove, force=True)
+                except Exception as e:
+                    errors.append(f"Container remove error: {e}")
+                finally:
+                    self.container = None
+
+        except Exception as e:
+            errors.append(f"General cleanup error: {e}")
+
+        if errors:
+            print(f"Warning: Errors during cleanup: {', '.join(errors)}")
+
+    async def __aenter__(self) -> "DockerSandbox":
+        """Async context manager entry."""
+        return await self.create()
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb) -> None:
+        """Async context manager exit."""
+        await self.cleanup()
diff --git a/app/sandbox/core/terminal.py b/app/sandbox/core/terminal.py
new file mode 100644
index 0000000..aee5184
--- /dev/null
+++ b/app/sandbox/core/terminal.py
@@ -0,0 +1,346 @@
+"""
+Asynchronous Docker Terminal
+
+This module provides asynchronous terminal functionality for Docker containers,
+allowing interactive command execution with timeout control.
+"""
+
+import asyncio
+import re
+import socket
+from typing import Dict, Optional, Tuple, Union
+
+import docker
+from docker import APIClient
+from docker.errors import APIError
+from docker.models.containers import Container
+
+
+class DockerSession:
+    def __init__(self, container_id: str) -> None:
+        """Initializes a Docker session.
+
+        Args:
+            container_id: ID of the Docker container.
+        """
+        self.api = APIClient()
+        self.container_id = container_id
+        self.exec_id = None
+        self.socket = None
+
+    async def create(self, working_dir: str, env_vars: Dict[str, str]) -> None:
+        """Creates an interactive session with the container.
+
+        Args:
+            working_dir: Working directory inside the container.
+            env_vars: Environment variables to set.
+
+        Raises:
+            RuntimeError: If socket connection fails.
+        """
+        startup_command = [
+            "bash",
+            "-c",
+            f"cd {working_dir} && "
+            "PROMPT_COMMAND='' "
+            "PS1='$ ' "
+            "exec bash --norc --noprofile",
+        ]
+
+        exec_data = self.api.exec_create(
+            self.container_id,
+            startup_command,
+            stdin=True,
+            tty=True,
+            stdout=True,
+            stderr=True,
+            privileged=True,
+            user="root",
+            environment={**env_vars, "TERM": "dumb", "PS1": "$ ", "PROMPT_COMMAND": ""},
+        )
+        self.exec_id = exec_data["Id"]
+
+        socket_data = self.api.exec_start(
+            self.exec_id, socket=True, tty=True, stream=True, demux=True
+        )
+
+        if hasattr(socket_data, "_sock"):
+            self.socket = socket_data._sock
+            self.socket.setblocking(False)
+        else:
+            raise RuntimeError("Failed to get socket connection")
+
+        await self._read_until_prompt()
+
+    async def close(self) -> None:
+        """Cleans up session resources.
+
+        1. Sends exit command
+        2. Closes socket connection
+        3. Checks and cleans up exec instance
+        """
+        try:
+            if self.socket:
+                # Send exit command to close bash session
+                try:
+                    self.socket.sendall(b"exit\n")
+                    # Allow time for command execution
+                    await asyncio.sleep(0.1)
+                except:
+                    pass  # Ignore sending errors, continue cleanup
+
+                # Close socket connection
+                try:
+                    self.socket.shutdown(socket.SHUT_RDWR)
+                except:
+                    pass  # Some platforms may not support shutdown
+
+                self.socket.close()
+                self.socket = None
+
+            if self.exec_id:
+                try:
+                    # Check exec instance status
+                    exec_inspect = self.api.exec_inspect(self.exec_id)
+                    if exec_inspect.get("Running", False):
+                        # If still running, wait for it to complete
+                        await asyncio.sleep(0.5)
+                except:
+                    pass  # Ignore inspection errors, continue cleanup
+
+                self.exec_id = None
+
+        except Exception as e:
+            # Log error but don't raise, ensure cleanup continues
+            print(f"Warning: Error during session cleanup: {e}")
+
+    async def _read_until_prompt(self) -> str:
+        """Reads output until prompt is found.
+
+        Returns:
+            String containing output up to the prompt.
+
+        Raises:
+            socket.error: If socket communication fails.
+        """
+        buffer = b""
+        while b"$ " not in buffer:
+            try:
+                chunk = self.socket.recv(4096)
+                if chunk:
+                    buffer += chunk
+            except socket.error as e:
+                if e.errno == socket.EWOULDBLOCK:
+                    await asyncio.sleep(0.1)
+                    continue
+                raise
+        return buffer.decode("utf-8")
+
+    async def execute(self, command: str, timeout: Optional[int] = None) -> str:
+        """Executes a command and returns cleaned output.
+
+        Args:
+            command: Shell command to execute.
+            timeout: Maximum execution time in seconds.
+
+        Returns:
+            Command output as string with prompt markers removed.
+
+        Raises:
+            RuntimeError: If session not initialized or execution fails.
+            TimeoutError: If command execution exceeds timeout.
+        """
+        if not self.socket:
+            raise RuntimeError("Session not initialized")
+
+        try:
+            # Sanitize command to prevent shell injection
+            sanitized_command = self._sanitize_command(command)
+            full_command = f"{sanitized_command}\necho $?\n"
+            self.socket.sendall(full_command.encode())
+
+            async def read_output() -> str:
+                buffer = b""
+                result_lines = []
+                command_sent = False
+
+                while True:
+                    try:
+                        chunk = self.socket.recv(4096)
+                        if not chunk:
+                            break
+
+                        buffer += chunk
+                        lines = buffer.split(b"\n")
+
+                        buffer = lines[-1]
+                        lines = lines[:-1]
+
+                        for line in lines:
+                            line = line.rstrip(b"\r")
+
+                            if not command_sent:
+                                command_sent = True
+                                continue
+
+                            if line.strip() == b"echo $?" or line.strip().isdigit():
+                                continue
+
+                            if line.strip():
+                                result_lines.append(line)
+
+                        if buffer.endswith(b"$ "):
+                            break
+
+                    except socket.error as e:
+                        if e.errno == socket.EWOULDBLOCK:
+                            await asyncio.sleep(0.1)
+                            continue
+                        raise
+
+                output = b"\n".join(result_lines).decode("utf-8")
+                output = re.sub(r"\n\$ echo \$\$?.*$", "", output)
+
+                return output
+
+            if timeout:
+                result = await asyncio.wait_for(read_output(), timeout)
+            else:
+                result = await read_output()
+
+            return result.strip()
+
+        except asyncio.TimeoutError:
+            raise TimeoutError(f"Command execution timed out after {timeout} seconds")
+        except Exception as e:
+            raise RuntimeError(f"Failed to execute command: {e}")
+
+    def _sanitize_command(self, command: str) -> str:
+        """Sanitizes the command string to prevent shell injection.
+
+        Args:
+            command: Raw command string.
+
+        Returns:
+            Sanitized command string.
+
+        Raises:
+            ValueError: If command contains potentially dangerous patterns.
+        """
+
+        # Additional checks for specific risky commands
+        risky_commands = [
+            "rm -rf /",
+            "rm -rf /*",
+            "mkfs",
+            "dd if=/dev/zero",
+            ":(){:|:&};:",
+            "chmod -R 777 /",
+            "chown -R",
+        ]
+
+        for risky in risky_commands:
+            if risky in command.lower():
+                raise ValueError(
+                    f"Command contains potentially dangerous operation: {risky}"
+                )
+
+        return command
+
+
+class AsyncDockerizedTerminal:
+    def __init__(
+        self,
+        container: Union[str, Container],
+        working_dir: str = "/workspace",
+        env_vars: Optional[Dict[str, str]] = None,
+        default_timeout: int = 60,
+    ) -> None:
+        """Initializes an asynchronous terminal for Docker containers.
+
+        Args:
+            container: Docker container ID or Container object.
+            working_dir: Working directory inside the container.
+            env_vars: Environment variables to set.
+            default_timeout: Default command execution timeout in seconds.
+        """
+        self.client = docker.from_env()
+        self.container = (
+            container
+            if isinstance(container, Container)
+            else self.client.containers.get(container)
+        )
+        self.working_dir = working_dir
+        self.env_vars = env_vars or {}
+        self.default_timeout = default_timeout
+        self.session = None
+
+    async def init(self) -> None:
+        """Initializes the terminal environment.
+
+        Ensures working directory exists and creates an interactive session.
+
+        Raises:
+            RuntimeError: If initialization fails.
+        """
+        await self._ensure_workdir()
+
+        self.session = DockerSession(self.container.id)
+        await self.session.create(self.working_dir, self.env_vars)
+
+    async def _ensure_workdir(self) -> None:
+        """Ensures working directory exists in container.
+
+        Raises:
+            RuntimeError: If directory creation fails.
+        """
+        try:
+            await self._exec_simple(f"mkdir -p {self.working_dir}")
+        except APIError as e:
+            raise RuntimeError(f"Failed to create working directory: {e}")
+
+    async def _exec_simple(self, cmd: str) -> Tuple[int, str]:
+        """Executes a simple command using Docker's exec_run.
+
+        Args:
+            cmd: Command to execute.
+
+        Returns:
+            Tuple of (exit_code, output).
+        """
+        result = await asyncio.to_thread(
+            self.container.exec_run, cmd, environment=self.env_vars
+        )
+        return result.exit_code, result.output.decode("utf-8")
+
+    async def run_command(self, cmd: str, timeout: Optional[int] = None) -> str:
+        """Runs a command in the container with timeout.
+
+        Args:
+            cmd: Shell command to execute.
+            timeout: Maximum execution time in seconds.
+
+        Returns:
+            Command output as string.
+
+        Raises:
+            RuntimeError: If terminal not initialized.
+        """
+        if not self.session:
+            raise RuntimeError("Terminal not initialized")
+
+        return await self.session.execute(cmd, timeout=timeout or self.default_timeout)
+
+    async def close(self) -> None:
+        """Closes the terminal session."""
+        if self.session:
+            await self.session.close()
+
+    async def __aenter__(self) -> "AsyncDockerizedTerminal":
+        """Async context manager entry."""
+        await self.init()
+        return self
+
+    async def __aexit__(self, exc_type, exc_val, exc_tb) -> None:
+        """Async context manager exit."""
+        await self.close()
diff --git a/app/tool/file_operators.py b/app/tool/file_operators.py
new file mode 100644
index 0000000..5f38d30
--- /dev/null
+++ b/app/tool/file_operators.py
@@ -0,0 +1,156 @@
+"""File operation interfaces and implementations for local and sandbox environments."""
+
+import asyncio
+from pathlib import Path
+from typing import Optional, Protocol, Tuple, Union, runtime_checkable
+
+from app.config import SandboxConfig
+from app.exceptions import ToolError
+from app.sandbox.client import SANDBOX_CLIENT
+
+
+PathLike = Union[str, Path]
+
+
+@runtime_checkable
+class FileOperator(Protocol):
+    """Interface for file operations in different environments."""
+
+    async def read_file(self, path: PathLike) -> str:
+        """Read content from a file."""
+        ...
+
+    async def write_file(self, path: PathLike, content: str) -> None:
+        """Write content to a file."""
+        ...
+
+    async def is_directory(self, path: PathLike) -> bool:
+        """Check if path points to a directory."""
+        ...
+
+    async def exists(self, path: PathLike) -> bool:
+        """Check if path exists."""
+        ...
+
+    async def run_command(
+        self, cmd: str, timeout: Optional[float] = 120.0
+    ) -> Tuple[int, str, str]:
+        """Run a shell command and return (return_code, stdout, stderr)."""
+        ...
+
+
+class LocalFileOperator(FileOperator):
+    """File operations implementation for local filesystem."""
+
+    async def read_file(self, path: PathLike) -> str:
+        """Read content from a local file."""
+        try:
+            return Path(path).read_text()
+        except Exception as e:
+            raise ToolError(f"Failed to read {path}: {str(e)}") from None
+
+    async def write_file(self, path: PathLike, content: str) -> None:
+        """Write content to a local file."""
+        try:
+            Path(path).write_text(content)
+        except Exception as e:
+            raise ToolError(f"Failed to write to {path}: {str(e)}") from None
+
+    async def is_directory(self, path: PathLike) -> bool:
+        """Check if path points to a directory."""
+        return Path(path).is_dir()
+
+    async def exists(self, path: PathLike) -> bool:
+        """Check if path exists."""
+        return Path(path).exists()
+
+    async def run_command(
+        self, cmd: str, timeout: Optional[float] = 120.0
+    ) -> Tuple[int, str, str]:
+        """Run a shell command locally."""
+        process = await asyncio.create_subprocess_shell(
+            cmd, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE
+        )
+
+        try:
+            stdout, stderr = await asyncio.wait_for(
+                process.communicate(), timeout=timeout
+            )
+            return (
+                process.returncode or 0,
+                stdout.decode(),
+                stderr.decode(),
+            )
+        except asyncio.TimeoutError as exc:
+            try:
+                process.kill()
+            except ProcessLookupError:
+                pass
+            raise TimeoutError(
+                f"Command '{cmd}' timed out after {timeout} seconds"
+            ) from exc
+
+
+class SandboxFileOperator(FileOperator):
+    """File operations implementation for sandbox environment."""
+
+    def __init__(self):
+        self.sandbox_client = SANDBOX_CLIENT
+
+    async def _ensure_sandbox_initialized(self):
+        """Ensure sandbox is initialized."""
+        if not self.sandbox_client.sandbox:
+            await self.sandbox_client.create(config=SandboxConfig())
+
+    async def read_file(self, path: PathLike) -> str:
+        """Read content from a file in sandbox."""
+        await self._ensure_sandbox_initialized()
+        try:
+            return await self.sandbox_client.read_file(str(path))
+        except Exception as e:
+            raise ToolError(f"Failed to read {path} in sandbox: {str(e)}") from None
+
+    async def write_file(self, path: PathLike, content: str) -> None:
+        """Write content to a file in sandbox."""
+        await self._ensure_sandbox_initialized()
+        try:
+            await self.sandbox_client.write_file(str(path), content)
+        except Exception as e:
+            raise ToolError(f"Failed to write to {path} in sandbox: {str(e)}") from None
+
+    async def is_directory(self, path: PathLike) -> bool:
+        """Check if path points to a directory in sandbox."""
+        await self._ensure_sandbox_initialized()
+        result = await self.sandbox_client.run_command(
+            f"test -d {path} && echo 'true' || echo 'false'"
+        )
+        return result.strip() == "true"
+
+    async def exists(self, path: PathLike) -> bool:
+        """Check if path exists in sandbox."""
+        await self._ensure_sandbox_initialized()
+        result = await self.sandbox_client.run_command(
+            f"test -e {path} && echo 'true' || echo 'false'"
+        )
+        return result.strip() == "true"
+
+    async def run_command(
+        self, cmd: str, timeout: Optional[float] = 120.0
+    ) -> Tuple[int, str, str]:
+        """Run a command in sandbox environment."""
+        await self._ensure_sandbox_initialized()
+        try:
+            stdout = await self.sandbox_client.run_command(
+                cmd, timeout=int(timeout) if timeout else None
+            )
+            return (
+                0,  # Always return 0 since we don't have explicit return code from sandbox
+                stdout,
+                "",  # No stderr capture in the current sandbox implementation
+            )
+        except TimeoutError as exc:
+            raise TimeoutError(
+                f"Command '{cmd}' timed out after {timeout} seconds in sandbox"
+            ) from exc
+        except Exception as exc:
+            return 1, "", f"Error executing command in sandbox: {str(exc)}"
diff --git a/app/tool/run.py b/app/tool/run.py
deleted file mode 100644
index 8896c58..0000000
--- a/app/tool/run.py
+++ /dev/null
@@ -1,43 +0,0 @@
-"""Utility to run shell commands asynchronously with a timeout."""
-
-import asyncio
-
-
-TRUNCATED_MESSAGE: str = "<response clipped><NOTE>To save on context only part of this file has been shown to you. You should retry this tool after you have searched inside the file with `grep -n` in order to find the line numbers of what you are looking for.</NOTE>"
-MAX_RESPONSE_LEN: int = 16000
-
-
-def maybe_truncate(content: str, truncate_after: int | None = MAX_RESPONSE_LEN):
-    """Truncate content and append a notice if content exceeds the specified length."""
-    return (
-        content
-        if not truncate_after or len(content) <= truncate_after
-        else content[:truncate_after] + TRUNCATED_MESSAGE
-    )
-
-
-async def run(
-    cmd: str,
-    timeout: float | None = 120.0,  # seconds
-    truncate_after: int | None = MAX_RESPONSE_LEN,
-):
-    """Run a shell command asynchronously with a timeout."""
-    process = await asyncio.create_subprocess_shell(
-        cmd, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE
-    )
-
-    try:
-        stdout, stderr = await asyncio.wait_for(process.communicate(), timeout=timeout)
-        return (
-            process.returncode or 0,
-            maybe_truncate(stdout.decode(), truncate_after=truncate_after),
-            maybe_truncate(stderr.decode(), truncate_after=truncate_after),
-        )
-    except asyncio.TimeoutError as exc:
-        try:
-            process.kill()
-        except ProcessLookupError:
-            pass
-        raise TimeoutError(
-            f"Command '{cmd}' timed out after {timeout} seconds"
-        ) from exc
diff --git a/app/tool/str_replace_editor.py b/app/tool/str_replace_editor.py
index 4094565..47e3d38 100644
--- a/app/tool/str_replace_editor.py
+++ b/app/tool/str_replace_editor.py
@@ -1,11 +1,18 @@
-from collections import defaultdict
-from pathlib import Path
-from typing import Literal, get_args
+"""File and directory manipulation tool with sandbox support."""
 
+from collections import defaultdict
+from typing import Any, DefaultDict, List, Literal, Optional, get_args
+
+from app.config import config
 from app.exceptions import ToolError
 from app.tool import BaseTool
 from app.tool.base import CLIResult, ToolResult
-from app.tool.run import run
+from app.tool.file_operators import (
+    FileOperator,
+    LocalFileOperator,
+    PathLike,
+    SandboxFileOperator,
+)
 
 
 Command = Literal[
@@ -15,12 +22,17 @@ Command = Literal[
     "insert",
     "undo_edit",
 ]
+
+# Constants
 SNIPPET_LINES: int = 4
-
 MAX_RESPONSE_LEN: int = 16000
+TRUNCATED_MESSAGE: str = (
+    "<response clipped><NOTE>To save on context only part of this file has been shown to you. "
+    "You should retry this tool after you have searched inside the file with `grep -n` "
+    "in order to find the line numbers of what you are looking for.</NOTE>"
+)
 
-TRUNCATED_MESSAGE: str = "<response clipped><NOTE>To save on context only part of this file has been shown to you. You should retry this tool after you have searched inside the file with `grep -n` in order to find the line numbers of what you are looking for.</NOTE>"
-
+# Tool description
 _STR_REPLACE_EDITOR_DESCRIPTION = """Custom editing tool for viewing, creating and editing files
 * State is persistent across command calls and discussions with the user
 * If `path` is a file, `view` displays the result of applying `cat -n`. If `path` is a directory, `view` lists non-hidden files and directories up to 2 levels deep
@@ -35,17 +47,17 @@ Notes for using the `str_replace` command:
 """
 
 
-def maybe_truncate(content: str, truncate_after: int | None = MAX_RESPONSE_LEN):
+def maybe_truncate(
+    content: str, truncate_after: Optional[int] = MAX_RESPONSE_LEN
+) -> str:
     """Truncate content and append a notice if content exceeds the specified length."""
-    return (
-        content
-        if not truncate_after or len(content) <= truncate_after
-        else content[:truncate_after] + TRUNCATED_MESSAGE
-    )
+    if not truncate_after or len(content) <= truncate_after:
+        return content
+    return content[:truncate_after] + TRUNCATED_MESSAGE
 
 
 class StrReplaceEditor(BaseTool):
-    """A tool for executing bash commands"""
+    """A tool for viewing, creating, and editing files with sandbox support."""
 
     name: str = "str_replace_editor"
     description: str = _STR_REPLACE_EDITOR_DESCRIPTION
@@ -85,8 +97,19 @@ class StrReplaceEditor(BaseTool):
         },
         "required": ["command", "path"],
     }
+    _file_history: DefaultDict[PathLike, List[str]] = defaultdict(list)
+    _local_operator: LocalFileOperator = LocalFileOperator()
+    # todo: Sandbox resources need to be destroyed at the appropriate time.
+    _sandbox_operator: SandboxFileOperator = SandboxFileOperator()
 
-    _file_history: list = defaultdict(list)
+    # def _get_operator(self, use_sandbox: bool) -> FileOperator:
+    def _get_operator(self) -> FileOperator:
+        """Get the appropriate file operator based on execution mode."""
+        return (
+            self._sandbox_operator
+            if config.sandbox.use_sandbox
+            else self._local_operator
+        )
 
     async def execute(
         self,
@@ -98,24 +121,30 @@ class StrReplaceEditor(BaseTool):
         old_str: str | None = None,
         new_str: str | None = None,
         insert_line: int | None = None,
-        **kwargs,
+        **kwargs: Any,
     ) -> str:
-        _path = Path(path)
-        self.validate_path(command, _path)
+        """Execute a file operation command."""
+        # Get the appropriate file operator
+        operator = self._get_operator()
+
+        # Validate path and command combination
+        await self.validate_path(command, path, operator)
+
+        # Execute the appropriate command
         if command == "view":
-            result = await self.view(_path, view_range)
+            result = await self.view(path, view_range, operator)
         elif command == "create":
             if file_text is None:
                 raise ToolError("Parameter `file_text` is required for command: create")
-            self.write_file(_path, file_text)
-            self._file_history[_path].append(file_text)
-            result = ToolResult(output=f"File created successfully at: {_path}")
+            await operator.write_file(path, file_text)
+            self._file_history[path].append(file_text)
+            result = ToolResult(output=f"File created successfully at: {path}")
         elif command == "str_replace":
             if old_str is None:
                 raise ToolError(
                     "Parameter `old_str` is required for command: str_replace"
                 )
-            result = self.str_replace(_path, old_str, new_str)
+            result = await self.str_replace(path, old_str, new_str, operator)
         elif command == "insert":
             if insert_line is None:
                 raise ToolError(
@@ -123,92 +152,149 @@ class StrReplaceEditor(BaseTool):
                 )
             if new_str is None:
                 raise ToolError("Parameter `new_str` is required for command: insert")
-            result = self.insert(_path, insert_line, new_str)
+            result = await self.insert(path, insert_line, new_str, operator)
         elif command == "undo_edit":
-            result = self.undo_edit(_path)
+            result = await self.undo_edit(path, operator)
         else:
+            # This should be caught by type checking, but we include it for safety
             raise ToolError(
                 f'Unrecognized command {command}. The allowed commands for the {self.name} tool are: {", ".join(get_args(Command))}'
             )
+
         return str(result)
 
-    def validate_path(self, command: str, path: Path):
-        """
-        Check that the path/command combination is valid.
-        """
-        # Check if its an absolute path
-        if not path.is_absolute():
-            suggested_path = Path("") / path
+    async def validate_path(
+        self, command: str, path: str, operator: FileOperator
+    ) -> None:
+        """Validate path and command combination based on execution environment."""
+        # Check if path is absolute
+        if not path.startswith("/"):
+            suggested_path = f"/{path}"
             raise ToolError(
-                f"The path {path} is not an absolute path, it should start with `/`. Maybe you meant {suggested_path}?"
+                f"The path {path} is not an absolute path, it should start with `/`. "
+                f"Maybe you meant {suggested_path}?"
             )
-        # Check if path exists
-        if not path.exists() and command != "create":
-            raise ToolError(
-                f"The path {path} does not exist. Please provide a valid path."
-            )
-        if path.exists() and command == "create":
-            raise ToolError(
-                f"File already exists at: {path}. Cannot overwrite files using command `create`."
-            )
-        # Check if the path points to a directory
-        if path.is_dir():
-            if command != "view":
+
+        # Only check if path exists for non-create commands
+        if command != "create":
+            if not await operator.exists(path):
+                raise ToolError(
+                    f"The path {path} does not exist. Please provide a valid path."
+                )
+
+            # Check if path is a directory
+            is_dir = await operator.is_directory(path)
+            if is_dir and command != "view":
                 raise ToolError(
                     f"The path {path} is a directory and only the `view` command can be used on directories"
                 )
 
-    async def view(self, path: Path, view_range: list[int] | None = None):
-        """Implement the view command"""
-        if path.is_dir():
+        # Check if file exists for create command
+        elif command == "create":
+            exists = await operator.exists(path)
+            if exists:
+                raise ToolError(
+                    f"File already exists at: {path}. Cannot overwrite files using command `create`."
+                )
+
+    async def view(
+        self,
+        path: PathLike,
+        view_range: Optional[List[int]] = None,
+        operator: FileOperator = None,
+    ) -> CLIResult:
+        """Display file or directory content."""
+        # Determine if path is a directory
+        is_dir = await operator.is_directory(path)
+
+        if is_dir:
+            # Directory handling
             if view_range:
                 raise ToolError(
                     "The `view_range` parameter is not allowed when `path` points to a directory."
                 )
 
-            _, stdout, stderr = await run(
-                rf"find {path} -maxdepth 2 -not -path '*/\.*'"
-            )
-            if not stderr:
-                stdout = f"Here's the files and directories up to 2 levels deep in {path}, excluding hidden items:\n{stdout}\n"
-            return CLIResult(output=stdout, error=stderr)
+            return await self._view_directory(path, operator)
+        else:
+            # File handling
+            return await self._view_file(path, operator, view_range)
 
-        file_content = self.read_file(path)
+    @staticmethod
+    async def _view_directory(path: PathLike, operator: FileOperator) -> CLIResult:
+        """Display directory contents."""
+        find_cmd = f"find {path} -maxdepth 2 -not -path '*/\\.*'"
+
+        # Execute command using the operator
+        returncode, stdout, stderr = await operator.run_command(find_cmd)
+
+        if not stderr:
+            stdout = (
+                f"Here's the files and directories up to 2 levels deep in {path}, "
+                f"excluding hidden items:\n{stdout}\n"
+            )
+
+        return CLIResult(output=stdout, error=stderr)
+
+    async def _view_file(
+        self,
+        path: PathLike,
+        operator: FileOperator,
+        view_range: Optional[List[int]] = None,
+    ) -> CLIResult:
+        """Display file content, optionally within a specified line range."""
+        # Read file content
+        file_content = await operator.read_file(path)
         init_line = 1
+
+        # Apply view range if specified
         if view_range:
             if len(view_range) != 2 or not all(isinstance(i, int) for i in view_range):
                 raise ToolError(
                     "Invalid `view_range`. It should be a list of two integers."
                 )
+
             file_lines = file_content.split("\n")
             n_lines_file = len(file_lines)
             init_line, final_line = view_range
+
+            # Validate view range
             if init_line < 1 or init_line > n_lines_file:
                 raise ToolError(
-                    f"Invalid `view_range`: {view_range}. Its first element `{init_line}` should be within the range of lines of the file: {[1, n_lines_file]}"
+                    f"Invalid `view_range`: {view_range}. Its first element `{init_line}` should be "
+                    f"within the range of lines of the file: {[1, n_lines_file]}"
                 )
             if final_line > n_lines_file:
                 raise ToolError(
-                    f"Invalid `view_range`: {view_range}. Its second element `{final_line}` should be smaller than the number of lines in the file: `{n_lines_file}`"
+                    f"Invalid `view_range`: {view_range}. Its second element `{final_line}` should be "
+                    f"smaller than the number of lines in the file: `{n_lines_file}`"
                 )
             if final_line != -1 and final_line < init_line:
                 raise ToolError(
-                    f"Invalid `view_range`: {view_range}. Its second element `{final_line}` should be larger or equal than its first `{init_line}`"
+                    f"Invalid `view_range`: {view_range}. Its second element `{final_line}` should be "
+                    f"larger or equal than its first `{init_line}`"
                 )
 
+            # Apply range
             if final_line == -1:
                 file_content = "\n".join(file_lines[init_line - 1 :])
             else:
                 file_content = "\n".join(file_lines[init_line - 1 : final_line])
 
+        # Format and return result
         return CLIResult(
             output=self._make_output(file_content, str(path), init_line=init_line)
         )
 
-    def str_replace(self, path: Path, old_str: str, new_str: str | None):
-        """Implement the str_replace command, which replaces old_str with new_str in the file content"""
-        # Read the file content
-        file_content = self.read_file(path).expandtabs()
+    async def str_replace(
+        self,
+        path: PathLike,
+        old_str: str,
+        new_str: Optional[str] = None,
+        operator: FileOperator = None,
+    ) -> CLIResult:
+        """Replace a unique string in a file with a new string."""
+        # Read file content and expand tabs
+        file_content = (await operator.read_file(path)).expandtabs()
         old_str = old_str.expandtabs()
         new_str = new_str.expandtabs() if new_str is not None else ""
 
@@ -219,6 +305,7 @@ class StrReplaceEditor(BaseTool):
                 f"No replacement was performed, old_str `{old_str}` did not appear verbatim in {path}."
             )
         elif occurrences > 1:
+            # Find line numbers of occurrences
             file_content_lines = file_content.split("\n")
             lines = [
                 idx + 1
@@ -226,16 +313,17 @@ class StrReplaceEditor(BaseTool):
                 if old_str in line
             ]
             raise ToolError(
-                f"No replacement was performed. Multiple occurrences of old_str `{old_str}` in lines {lines}. Please ensure it is unique"
+                f"No replacement was performed. Multiple occurrences of old_str `{old_str}` "
+                f"in lines {lines}. Please ensure it is unique"
             )
 
         # Replace old_str with new_str
         new_file_content = file_content.replace(old_str, new_str)
 
         # Write the new content to the file
-        self.write_file(path, new_file_content)
+        await operator.write_file(path, new_file_content)
 
-        # Save the content to history
+        # Save the original content to history
         self._file_history[path].append(file_content)
 
         # Create a snippet of the edited section
@@ -253,36 +341,50 @@ class StrReplaceEditor(BaseTool):
 
         return CLIResult(output=success_msg)
 
-    def insert(self, path: Path, insert_line: int, new_str: str):
-        """Implement the insert command, which inserts new_str at the specified line in the file content."""
-        file_text = self.read_file(path).expandtabs()
+    async def insert(
+        self,
+        path: PathLike,
+        insert_line: int,
+        new_str: str,
+        operator: FileOperator = None,
+    ) -> CLIResult:
+        """Insert text at a specific line in a file."""
+        # Read and prepare content
+        file_text = (await operator.read_file(path)).expandtabs()
         new_str = new_str.expandtabs()
         file_text_lines = file_text.split("\n")
         n_lines_file = len(file_text_lines)
 
+        # Validate insert_line
         if insert_line < 0 or insert_line > n_lines_file:
             raise ToolError(
-                f"Invalid `insert_line` parameter: {insert_line}. It should be within the range of lines of the file: {[0, n_lines_file]}"
+                f"Invalid `insert_line` parameter: {insert_line}. It should be within "
+                f"the range of lines of the file: {[0, n_lines_file]}"
             )
 
+        # Perform insertion
         new_str_lines = new_str.split("\n")
         new_file_text_lines = (
             file_text_lines[:insert_line]
             + new_str_lines
             + file_text_lines[insert_line:]
         )
+
+        # Create a snippet for preview
         snippet_lines = (
             file_text_lines[max(0, insert_line - SNIPPET_LINES) : insert_line]
             + new_str_lines
             + file_text_lines[insert_line : insert_line + SNIPPET_LINES]
         )
 
+        # Join lines and write to file
         new_file_text = "\n".join(new_file_text_lines)
         snippet = "\n".join(snippet_lines)
 
-        self.write_file(path, new_file_text)
+        await operator.write_file(path, new_file_text)
         self._file_history[path].append(file_text)
 
+        # Prepare success message
         success_msg = f"The file {path} has been edited. "
         success_msg += self._make_output(
             snippet,
@@ -290,51 +392,43 @@ class StrReplaceEditor(BaseTool):
             max(1, insert_line - SNIPPET_LINES + 1),
         )
         success_msg += "Review the changes and make sure they are as expected (correct indentation, no duplicate lines, etc). Edit the file again if necessary."
+
         return CLIResult(output=success_msg)
 
-    def undo_edit(self, path: Path):
-        """Implement the undo_edit command."""
+    async def undo_edit(
+        self, path: PathLike, operator: FileOperator = None
+    ) -> CLIResult:
+        """Revert the last edit made to a file."""
         if not self._file_history[path]:
             raise ToolError(f"No edit history found for {path}.")
 
         old_text = self._file_history[path].pop()
-        self.write_file(path, old_text)
+        await operator.write_file(path, old_text)
 
         return CLIResult(
             output=f"Last edit to {path} undone successfully. {self._make_output(old_text, str(path))}"
         )
 
-    def read_file(self, path: Path):
-        """Read the content of a file from a given path; raise a ToolError if an error occurs."""
-        try:
-            return path.read_text()
-        except Exception as e:
-            raise ToolError(f"Ran into {e} while trying to read {path}") from None
-
-    def write_file(self, path: Path, file: str):
-        """Write the content of a file to a given path; raise a ToolError if an error occurs."""
-        try:
-            path.write_text(file)
-        except Exception as e:
-            raise ToolError(f"Ran into {e} while trying to write to {path}") from None
-
     def _make_output(
         self,
         file_content: str,
         file_descriptor: str,
         init_line: int = 1,
         expand_tabs: bool = True,
-    ):
-        """Generate output for the CLI based on the content of a file."""
+    ) -> str:
+        """Format file content for display with line numbers."""
         file_content = maybe_truncate(file_content)
         if expand_tabs:
             file_content = file_content.expandtabs()
+
+        # Add line numbers to each line
         file_content = "\n".join(
             [
                 f"{i + init_line:6}\t{line}"
                 for i, line in enumerate(file_content.split("\n"))
             ]
         )
+
         return (
             f"Here's the result of running `cat -n` on {file_descriptor}:\n"
             + file_content
diff --git a/config/config.example.toml b/config/config.example.toml
index de71832..68d6a62 100644
--- a/config/config.example.toml
+++ b/config/config.example.toml
@@ -11,3 +11,13 @@ temperature = 0.0
 model = "claude-3-5-sonnet"
 base_url = "https://api.openai.com/v1"
 api_key = "sk-..."
+
+# Sandbox configuration
+[sandbox]
+use_sandbox = false
+image = "python:3.10-slim"
+work_dir = "/workspace"
+memory_limit = "1g"  # 512m
+cpu_limit = 2.0
+timeout = 300
+network_enabled = false
diff --git a/requirements.txt b/requirements.txt
index a4128d2..eae7eff 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,3 +19,7 @@ aiofiles~=24.1.0
 pydantic_core~=2.27.2
 colorama~=0.4.6
 playwright~=1.49.1
+
+docker~=7.1.0
+pytest~=8.3.5
+pytest-asyncio~=0.25.3
diff --git a/tests/sandbox/test_client.py b/tests/sandbox/test_client.py
new file mode 100644
index 0000000..5b05fed
--- /dev/null
+++ b/tests/sandbox/test_client.py
@@ -0,0 +1,110 @@
+import tempfile
+from pathlib import Path
+from typing import AsyncGenerator
+
+import pytest
+import pytest_asyncio
+
+from app.config import SandboxConfig
+from app.sandbox.client import LocalSandboxClient, create_sandbox_client
+
+
+@pytest_asyncio.fixture(scope="function")
+async def local_client() -> AsyncGenerator[LocalSandboxClient, None]:
+    """Creates a local sandbox client for testing."""
+    client = await create_sandbox_client()
+    try:
+        yield client
+    finally:
+        await client.cleanup()
+
+
+@pytest.fixture(scope="function")
+def temp_dir() -> Path:
+    """Creates a temporary directory for testing."""
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        yield Path(tmp_dir)
+
+
+@pytest.mark.asyncio
+async def test_sandbox_creation(local_client: LocalSandboxClient):
+    """Tests sandbox creation with specific configuration."""
+    config = SandboxConfig(
+        image="python:3.10-slim",
+        work_dir="/workspace",
+        memory_limit="512m",
+        cpu_limit=0.5,
+    )
+
+    await local_client.create(config)
+    result = await local_client.run_command("python3 --version")
+    assert "Python 3.10" in result
+
+
+@pytest.mark.asyncio
+async def test_local_command_execution(local_client: LocalSandboxClient):
+    """Tests command execution in local sandbox."""
+    await local_client.create()
+
+    result = await local_client.run_command("echo 'test'")
+    assert result.strip() == "test"
+
+    with pytest.raises(Exception):
+        await local_client.run_command("sleep 10", timeout=1)
+
+
+@pytest.mark.asyncio
+async def test_local_file_operations(local_client: LocalSandboxClient, temp_dir: Path):
+    """Tests file operations in local sandbox."""
+    await local_client.create()
+
+    # Test write and read operations
+    test_content = "Hello, World!"
+    await local_client.write_file("/workspace/test.txt", test_content)
+    content = await local_client.read_file("/workspace/test.txt")
+    assert content.strip() == test_content
+
+    # Test copying file to container
+    src_file = temp_dir / "src.txt"
+    src_file.write_text("Copy to container")
+    await local_client.copy_to(str(src_file), "/workspace/copied.txt")
+    content = await local_client.read_file("/workspace/copied.txt")
+    assert content.strip() == "Copy to container"
+
+    # Test copying file from container
+    dst_file = temp_dir / "dst.txt"
+    await local_client.copy_from("/workspace/test.txt", str(dst_file))
+    assert dst_file.read_text().strip() == test_content
+
+
+@pytest.mark.asyncio
+async def test_local_volume_binding(local_client: LocalSandboxClient, temp_dir: Path):
+    """Tests volume binding in local sandbox."""
+    bind_path = str(temp_dir)
+    volume_bindings = {bind_path: "/data"}
+
+    await local_client.create(volume_bindings=volume_bindings)
+
+    test_file = temp_dir / "test.txt"
+    test_file.write_text("Volume test")
+
+    content = await local_client.read_file("/data/test.txt")
+    assert "Volume test" in content
+
+
+@pytest.mark.asyncio
+async def test_local_error_handling(local_client: LocalSandboxClient):
+    """Tests error handling in local sandbox."""
+    await local_client.create()
+
+    with pytest.raises(Exception) as exc:
+        await local_client.read_file("/nonexistent.txt")
+    assert "not found" in str(exc.value).lower()
+
+    with pytest.raises(Exception) as exc:
+        await local_client.copy_from("/nonexistent.txt", "local.txt")
+    assert "not found" in str(exc.value).lower()
+
+
+if __name__ == "__main__":
+    pytest.main(["-v", __file__])
diff --git a/tests/sandbox/test_docker_terminal.py b/tests/sandbox/test_docker_terminal.py
new file mode 100644
index 0000000..7903d95
--- /dev/null
+++ b/tests/sandbox/test_docker_terminal.py
@@ -0,0 +1,104 @@
+"""Tests for the AsyncDockerizedTerminal implementation."""
+
+import docker
+import pytest
+import pytest_asyncio
+
+from app.sandbox.core.terminal import AsyncDockerizedTerminal
+
+
+@pytest.fixture(scope="module")
+def docker_client():
+    """Fixture providing a Docker client."""
+    return docker.from_env()
+
+
+@pytest_asyncio.fixture(scope="module")
+async def docker_container(docker_client):
+    """Fixture providing a test Docker container."""
+    container = docker_client.containers.run(
+        "python:3.10-slim",
+        "tail -f /dev/null",
+        name="test_container",
+        detach=True,
+        remove=True,
+    )
+    yield container
+    container.stop()
+
+
+@pytest_asyncio.fixture
+async def terminal(docker_container):
+    """Fixture providing an initialized AsyncDockerizedTerminal instance."""
+    terminal = AsyncDockerizedTerminal(
+        docker_container,
+        working_dir="/workspace",
+        env_vars={"TEST_VAR": "test_value"},
+        default_timeout=30,
+    )
+    await terminal.init()
+    yield terminal
+    await terminal.close()
+
+
+class TestAsyncDockerizedTerminal:
+    """Test cases for AsyncDockerizedTerminal."""
+
+    @pytest.mark.asyncio
+    async def test_basic_command_execution(self, terminal):
+        """Test basic command execution functionality."""
+        result = await terminal.run_command("echo 'Hello World'")
+        assert "Hello World" in result
+
+    @pytest.mark.asyncio
+    async def test_environment_variables(self, terminal):
+        """Test environment variable setting and access."""
+        result = await terminal.run_command("echo $TEST_VAR")
+        assert "test_value" in result
+
+    @pytest.mark.asyncio
+    async def test_working_directory(self, terminal):
+        """Test working directory setup."""
+        result = await terminal.run_command("pwd")
+        assert "/workspace" == result
+
+    @pytest.mark.asyncio
+    async def test_command_timeout(self, docker_container):
+        """Test command timeout functionality."""
+        terminal = AsyncDockerizedTerminal(docker_container, default_timeout=1)
+        await terminal.init()
+        try:
+            with pytest.raises(TimeoutError):
+                await terminal.run_command("sleep 5")
+        finally:
+            await terminal.close()
+
+    @pytest.mark.asyncio
+    async def test_multiple_commands(self, terminal):
+        """Test execution of multiple commands in sequence."""
+        cmd1 = await terminal.run_command("echo 'First'")
+        cmd2 = await terminal.run_command("echo 'Second'")
+        assert "First" in cmd1
+        assert "Second" in cmd2
+
+    @pytest.mark.asyncio
+    async def test_session_cleanup(self, docker_container):
+        """Test proper cleanup of resources."""
+        terminal = AsyncDockerizedTerminal(docker_container)
+        await terminal.init()
+        assert terminal.session is not None
+        await terminal.close()
+        # Verify session is properly cleaned up
+        # Note: session object still exists, but internal connection is closed
+        assert terminal.session is not None
+
+
+# Configure pytest-asyncio
+def pytest_configure(config):
+    """Configure pytest-asyncio."""
+    config.addinivalue_line("asyncio_mode", "strict")
+    config.addinivalue_line("asyncio_default_fixture_loop_scope", "function")
+
+
+if __name__ == "__main__":
+    pytest.main(["-v", __file__])
diff --git a/tests/sandbox/test_sandbox.py b/tests/sandbox/test_sandbox.py
new file mode 100644
index 0000000..a690c98
--- /dev/null
+++ b/tests/sandbox/test_sandbox.py
@@ -0,0 +1,152 @@
+import pytest
+import pytest_asyncio
+
+from app.sandbox.core.sandbox import DockerSandbox, SandboxConfig
+
+
+@pytest.fixture(scope="module")
+def sandbox_config():
+    """Creates sandbox configuration for testing."""
+    return SandboxConfig(
+        image="python:3.10-slim",
+        work_dir="/workspace",
+        memory_limit="1g",
+        cpu_limit=0.5,
+        network_enabled=True,
+    )
+
+
+@pytest_asyncio.fixture(scope="module")
+async def sandbox(sandbox_config):
+    """Creates and manages a test sandbox instance."""
+    sandbox = DockerSandbox(sandbox_config)
+    await sandbox.create()
+    try:
+        yield sandbox
+    finally:
+        await sandbox.cleanup()
+
+
+@pytest.mark.asyncio
+async def test_sandbox_working_directory(sandbox):
+    """Tests sandbox working directory configuration."""
+    result = await sandbox.terminal.run_command("pwd")
+    assert result.strip() == "/workspace"
+
+
+@pytest.mark.asyncio
+async def test_sandbox_file_operations(sandbox):
+    """Tests sandbox file read/write operations."""
+    # Test file writing
+    test_content = "Hello from sandbox!"
+    await sandbox.write_file("/workspace/test.txt", test_content)
+
+    # Test file reading
+    content = await sandbox.read_file("/workspace/test.txt")
+    assert content.strip() == test_content
+
+
+@pytest.mark.asyncio
+async def test_sandbox_python_execution(sandbox):
+    """Tests Python code execution in sandbox."""
+    # Write test file
+    await sandbox.write_file("/workspace/test.txt", "Hello from file!")
+
+    # Write Python script
+    python_code = """
+print("Hello from Python!")
+with open('/workspace/test.txt') as f:
+    print(f.read())
+"""
+    await sandbox.write_file("/workspace/test.py", python_code)
+
+    # Execute script and verify output
+    result = await sandbox.terminal.run_command("python3 /workspace/test.py")
+    assert "Hello from Python!" in result
+    assert "Hello from file!" in result
+
+
+@pytest.mark.asyncio
+async def test_sandbox_file_persistence(sandbox):
+    """Tests file persistence in sandbox."""
+    # Create multiple files
+    files = {
+        "file1.txt": "Content 1",
+        "file2.txt": "Content 2",
+        "nested/file3.txt": "Content 3",
+    }
+
+    # Write files
+    for path, content in files.items():
+        await sandbox.write_file(f"/workspace/{path}", content)
+
+    # Verify file contents
+    for path, expected_content in files.items():
+        content = await sandbox.read_file(f"/workspace/{path}")
+        assert content.strip() == expected_content
+
+
+@pytest.mark.asyncio
+async def test_sandbox_python_environment(sandbox):
+    """Tests Python environment configuration."""
+    # Test Python version
+    result = await sandbox.terminal.run_command("python3 --version")
+    assert "Python 3.10" in result
+
+    # Test basic module imports
+    python_code = """
+import sys
+import os
+import json
+print("Python is working!")
+"""
+    await sandbox.write_file("/workspace/env_test.py", python_code)
+    result = await sandbox.terminal.run_command("python3 /workspace/env_test.py")
+    assert "Python is working!" in result
+
+
+@pytest.mark.asyncio
+async def test_sandbox_network_access(sandbox):
+    """Tests sandbox network access."""
+    if not sandbox.config.network_enabled:
+        pytest.skip("Network access is disabled")
+
+    # Test network connectivity
+    await sandbox.terminal.run_command("apt update && apt install curl -y")
+    result = await sandbox.terminal.run_command("curl -I https://www.example.com")
+    assert "HTTP/2 200" in result
+
+
+@pytest.mark.asyncio
+async def test_sandbox_cleanup(sandbox_config):
+    """Tests sandbox cleanup process."""
+    sandbox = DockerSandbox(sandbox_config)
+    await sandbox.create()
+
+    # Create test files
+    await sandbox.write_file("/workspace/test.txt", "test")
+    container_id = sandbox.terminal.container.id
+    # Perform cleanup
+    await sandbox.cleanup()
+
+    # Verify container has been removed
+    import docker
+
+    client = docker.from_env()
+    containers = client.containers.list(all=True)
+    assert not any(c.id == container_id for c in containers)
+
+
+@pytest.mark.asyncio
+async def test_sandbox_error_handling():
+    """Tests error handling with invalid configuration."""
+    # Test invalid configuration
+    invalid_config = SandboxConfig(image="nonexistent:latest", work_dir="/invalid")
+
+    sandbox = DockerSandbox(invalid_config)
+    with pytest.raises(Exception):
+        await sandbox.create()
+
+
+if __name__ == "__main__":
+    pytest.main(["-v", __file__])
diff --git a/tests/sandbox/test_sandbox_manager.py b/tests/sandbox/test_sandbox_manager.py
new file mode 100644
index 0000000..09f498d
--- /dev/null
+++ b/tests/sandbox/test_sandbox_manager.py
@@ -0,0 +1,138 @@
+import asyncio
+import os
+import tempfile
+from typing import AsyncGenerator
+
+import pytest
+import pytest_asyncio
+
+from app.sandbox.core.manager import SandboxManager
+
+
+@pytest_asyncio.fixture(scope="function")
+async def manager() -> AsyncGenerator[SandboxManager, None]:
+    """Creates a sandbox manager instance.
+
+    Uses function scope to ensure each test case has its own manager instance.
+    """
+    manager = SandboxManager(max_sandboxes=2, idle_timeout=60, cleanup_interval=30)
+    try:
+        yield manager
+    finally:
+        # Ensure all resources are cleaned up
+        await manager.cleanup()
+
+
+@pytest.fixture
+def temp_file():
+    """Creates a temporary test file."""
+    with tempfile.NamedTemporaryFile(mode="w+", delete=False) as f:
+        f.write("test content")
+        path = f.name
+    try:
+        yield path
+    finally:
+        if os.path.exists(path):
+            os.unlink(path)
+
+
+@pytest.mark.asyncio
+async def test_create_sandbox(manager):
+    """Tests sandbox creation."""
+    # Create default sandbox
+    sandbox_id = await manager.create_sandbox()
+    assert sandbox_id in manager._sandboxes
+    assert sandbox_id in manager._last_used
+
+    # Verify sandbox functionality
+    sandbox = await manager.get_sandbox(sandbox_id)
+    result = await sandbox.run_command("echo 'test'")
+    assert result.strip() == "test"
+
+
+@pytest.mark.asyncio
+async def test_max_sandboxes_limit(manager):
+    """Tests maximum sandbox limit enforcement."""
+    created_sandboxes = []
+    try:
+        # Create maximum number of sandboxes
+        for _ in range(manager.max_sandboxes):
+            sandbox_id = await manager.create_sandbox()
+            created_sandboxes.append(sandbox_id)
+
+        # Verify created sandbox count
+        assert len(manager._sandboxes) == manager.max_sandboxes
+
+        # Attempting to create additional sandbox should fail
+        with pytest.raises(RuntimeError) as exc_info:
+            await manager.create_sandbox()
+
+        # Verify error message
+        expected_message = (
+            f"Maximum number of sandboxes ({manager.max_sandboxes}) reached"
+        )
+        assert str(exc_info.value) == expected_message
+
+    finally:
+        # Clean up all created sandboxes
+        for sandbox_id in created_sandboxes:
+            try:
+                await manager.delete_sandbox(sandbox_id)
+            except Exception as e:
+                print(f"Failed to cleanup sandbox {sandbox_id}: {e}")
+
+
+@pytest.mark.asyncio
+async def test_get_nonexistent_sandbox(manager):
+    """Tests retrieving a non-existent sandbox."""
+    with pytest.raises(KeyError, match="Sandbox .* not found"):
+        await manager.get_sandbox("nonexistent-id")
+
+
+@pytest.mark.asyncio
+async def test_sandbox_cleanup(manager):
+    """Tests sandbox cleanup functionality."""
+    sandbox_id = await manager.create_sandbox()
+    assert sandbox_id in manager._sandboxes
+
+    await manager.delete_sandbox(sandbox_id)
+    assert sandbox_id not in manager._sandboxes
+    assert sandbox_id not in manager._last_used
+
+
+@pytest.mark.asyncio
+async def test_idle_sandbox_cleanup(manager):
+    """Tests automatic cleanup of idle sandboxes."""
+    # Set short idle timeout
+    manager.idle_timeout = 0.1
+
+    sandbox_id = await manager.create_sandbox()
+    assert sandbox_id in manager._sandboxes
+
+    # Wait longer than idle timeout
+    await asyncio.sleep(0.2)
+
+    # Trigger cleanup
+    await manager._cleanup_idle_sandboxes()
+    assert sandbox_id not in manager._sandboxes
+
+
+@pytest.mark.asyncio
+async def test_manager_cleanup(manager):
+    """Tests manager cleanup functionality."""
+    # Create multiple sandboxes
+    sandbox_ids = []
+    for _ in range(2):
+        sandbox_id = await manager.create_sandbox()
+        sandbox_ids.append(sandbox_id)
+
+    # Clean up all resources
+    await manager.cleanup()
+
+    # Verify all sandboxes have been cleaned up
+    assert not manager._sandboxes
+    assert not manager._last_used
+
+
+if __name__ == "__main__":
+    pytest.main(["-v", __file__])