diff --git a/server/routers/devserver.py b/server/routers/devserver.py
index 18f91ec1..7feab550 100644
--- a/server/routers/devserver.py
+++ b/server/routers/devserver.py
@@ -6,8 +6,9 @@
 Uses project registry for path lookups and project_config for command detection.
 """
 
-import re
+import logging
 import sys
+import shlex
 from pathlib import Path
 
 from fastapi import APIRouter, HTTPException
@@ -26,36 +27,328 @@
     get_project_config,
     set_dev_command,
 )
+from ..utils.project_helpers import get_project_path as _get_project_path
+from ..utils.validation import validate_project_name
 
-# Add root to path for registry import
+# Add root to path for security module import
 _root = Path(__file__).parent.parent.parent
 if str(_root) not in sys.path:
     sys.path.insert(0, str(_root))
 
-from registry import get_project_path as registry_get_project_path
+from security import extract_commands, get_effective_commands, is_command_allowed
 
-
-def _get_project_path(project_name: str) -> Path | None:
-    """Get project path from registry."""
-    return registry_get_project_path(project_name)
+logger = logging.getLogger(__name__)
 
 
 router = APIRouter(prefix="/api/projects/{project_name}/devserver", tags=["devserver"])
 
 
+def get_project_dir(project_name: str) -> Path:
+    """
+    Get the validated project directory for a project name.
+
+    Args:
+        project_name: Name of the project
+
+    Returns:
+        Path to the project directory
+
+    Raises:
+        HTTPException: If project is not found or directory does not exist
+    """
+    project_name = validate_project_name(project_name)
+    project_dir = _get_project_path(project_name)
+
+    if not project_dir:
+        raise HTTPException(
+            status_code=404,
+            detail=f"Project '{project_name}' not found in registry"
+        )
+
+    if not project_dir.exists():
+        raise HTTPException(
+            status_code=404,
+            detail=f"Project directory not found: {project_dir}"
+        )
+
+    return project_dir
+
+ALLOWED_RUNNERS = {"npm", "pnpm", "yarn", "uvicorn", "python", "python3"}
+
+def validate_custom_command_strict(cmd: str) -> None:
+    """
+    Strict allowlist validation for dev server commands.
+    Prevents arbitrary command execution (no sh -c, no cmd /c, no python -c, etc.)
+    """
+    if not isinstance(cmd, str) or not cmd.strip():
+        raise ValueError("custom_command cannot be empty")
+
+    argv = shlex.split(cmd, posix=(sys.platform != "win32"))
+    if not argv:
+        raise ValueError("custom_command could not be parsed")
+
+    base = Path(argv[0]).name.lower()
+
+    # Block direct shells / interpreters commonly used for command injection
+    if base in {"sh", "bash", "zsh", "cmd", "powershell", "pwsh"}:
+        raise ValueError(f"custom_command runner not allowed: {base}")
+
+    if base not in ALLOWED_RUNNERS:
+        raise ValueError(f"custom_command runner not allowed: {base}")
+
+    # Block one-liner execution
+    lowered = [a.lower() for a in argv]
+    if base in {"python", "python3"}:
+        if "-c" in lowered:
+            raise ValueError("python -c is not allowed")
+        # Only allow: python -m uvicorn ...
+        if len(argv) < 3 or argv[1:3] != ["-m", "uvicorn"]:
+            raise ValueError("Only 'python -m uvicorn ...' is allowed")
+
+    if base == "uvicorn":
+        if len(argv) < 2 or ":" not in argv[1]:
+            raise ValueError("uvicorn must specify an app like module:app")
+
+        allowed_flags = {"--host", "--port", "--reload", "--log-level", "--workers"}
+        i = 2
+        while i < len(argv):
+            a = argv[i]
+            if a.startswith("-") and a not in allowed_flags:
+                raise ValueError(f"uvicorn flag not allowed: {a}")
+            i += 1
+
+    if base in {"npm", "pnpm", "yarn"}:
+        # Allow only dev/start scripts (no arbitrary exec)
+        if base == "npm":
+            if len(argv) < 3 or argv[1] != "run" or argv[2] not in {"dev", "start"}:
+                raise ValueError("npm custom_command must be 'npm run dev' or 'npm run start'")
+        elif base == "pnpm":
+            ok = (len(argv) >= 2 and argv[1] in {"dev", "start"}) or (len(argv) >= 3 and argv[1] == "run" and argv[2] in {"dev", "start"})
+            if not ok:
+                raise ValueError("pnpm custom_command must be 'pnpm dev/start' or 'pnpm run dev/start'")
+        elif base == "yarn":
+            ok = (len(argv) >= 2 and argv[1] in {"dev", "start"}) or (len(argv) >= 3 and argv[1] == "run" and argv[2] in {"dev", "start"})
+            if not ok:
+                raise ValueError("yarn custom_command must be 'yarn dev/start' or 'yarn run dev/start'")
+
+def get_project_devserver_manager(project_name: str):
+    """
+    Get the dev server process manager for a project.
+
+    Args:
+        project_name: Name of the project
+
+    Returns:
+        DevServerProcessManager instance for the project
+
+    Raises:
+        HTTPException: If project is not found or directory does not exist
+    """
+    project_dir = get_project_dir(project_name)
+    return get_devserver_manager(project_name, project_dir)
+
+
+def validate_dev_command(command: str, project_dir: Path) -> None:
+    """
+    Validate a dev server command against the security allowlist.
+
+    Extracts all commands from the shell string and checks each against
+    the effective allowlist (global + org + project). Raises HTTPException
+    if any command is blocked or not allowed.
+
+    Args:
+        command: The shell command string to validate
+        project_dir: Project directory for loading project-level allowlists
+
+    Raises:
+        HTTPException 400: If the command fails validation
+    """
+    commands = extract_commands(command)
+    if not commands:
+        raise HTTPException(
+            status_code=400,
+            detail="Could not parse command for security validation"
+        )
+
+    allowed_commands, blocked_commands = get_effective_commands(project_dir)
+
+    for cmd in commands:
+        if cmd in blocked_commands:
+            logger.warning("Blocked dev server command '%s' (in blocklist) for project dir %s", cmd, project_dir)
+            raise HTTPException(
+                status_code=400,
+                detail=f"Command '{cmd}' is blocked and cannot be used as a dev server command"
+            )
+        if not is_command_allowed(cmd, allowed_commands):
+            logger.warning("Rejected dev server command '%s' (not in allowlist) for project dir %s", cmd, project_dir)
+            raise HTTPException(
+                status_code=400,
+                detail=f"Command '{cmd}' is not in the allowed commands list"
+            )
+
+
 # ============================================================================
-# Helper Functions
+# Endpoints
 # ============================================================================
 
 
-def validate_project_name(name: str) -> str:
-    """Validate and sanitize project name to prevent path traversal."""
-    if not re.match(r'^[a-zA-Z0-9_-]{1,50}$', name):
+@router.get("/status", response_model=DevServerStatus)
+async def get_devserver_status(project_name: str) -> DevServerStatus:
+    """
+    Get the current status of the dev server for a project.
+
+    Returns information about whether the dev server is running,
+    its process ID, detected URL, and the command used to start it.
+    """
+    manager = get_project_devserver_manager(project_name)
+
+    # Run healthcheck to detect crashed processes
+    await manager.healthcheck()
+
+    return DevServerStatus(
+        status=manager.status,
+        pid=manager.pid,
+        url=manager.detected_url,
+        command=manager._command,
+        started_at=manager.started_at.isoformat() if manager.started_at else None,
+    )
+
+
+@router.post("/start", response_model=DevServerActionResponse)
+async def start_devserver(
+    project_name: str,
+    request: DevServerStartRequest = DevServerStartRequest(),
+) -> DevServerActionResponse:
+    """
+    Start the dev server for a project.
+
+    If a custom command is provided in the request, it will be used.
+    Otherwise, the effective command from the project configuration is used.
+
+    Args:
+        project_name: Name of the project
+        request: Optional start request with custom command
+
+    Returns:
+        Response indicating success/failure and current status
+    """
+    manager = get_project_devserver_manager(project_name)
+    project_dir = get_project_dir(project_name)
+
+    # Determine which command to use
+    command: str | None
+    if request.command:
         raise HTTPException(
             status_code=400,
-            detail="Invalid project name"
+            detail="Direct command execution is disabled. Use /config to set a safe custom_command."
         )
-    return name
+    else:
+        command = get_dev_command(project_dir)
+
+    if not command:
+        raise HTTPException(
+            status_code=400,
+            detail="No dev command available. Configure a custom command or ensure project type can be detected."
+        )
+
+    # Validate command against security allowlist before execution
+    validate_dev_command(command, project_dir)
+
+    # Now command is definitely str and validated
+    success, message = await manager.start(command)
+
+    return DevServerActionResponse(
+        success=success,
+        status=manager.status,
+        message=message,
+    )
+
+
+@router.post("/stop", response_model=DevServerActionResponse)
+async def stop_devserver(project_name: str) -> DevServerActionResponse:
+    """
+    Stop the dev server for a project.
+
+    Gracefully terminates the dev server process and all its child processes.
+
+    Args:
+        project_name: Name of the project
+
+    Returns:
+        Response indicating success/failure and current status
+    """
+    manager = get_project_devserver_manager(project_name)
+
+    success, message = await manager.stop()
+
+    return DevServerActionResponse(
+        success=success,
+        status=manager.status,
+        message=message,
+    )
+
+
+@router.get("/config", response_model=DevServerConfigResponse)
+async def get_devserver_config(project_name: str) -> DevServerConfigResponse:
+    """
+    Get the dev server configuration for a project.
+
+    Returns information about:
+    - detected_type: The auto-detected project type (nodejs-vite, python-django, etc.)
+    - detected_command: The default command for the detected type
+    - custom_command: Any user-configured custom command
+    - effective_command: The command that will actually be used (custom or detected)
+
+    Args:
+        project_name: Name of the project
+
+    Returns:
+        Configuration details for the project's dev server
+    """
+    project_dir = get_project_dir(project_name)
+    config = get_project_config(project_dir)"""
+Dev Server Router
+=================
+
+API endpoints for dev server control (start/stop) and configuration.
+Uses project registry for path lookups and project_config for command detection.
+"""
+
+import logging
+import sys
+import shlex
+from pathlib import Path
+
+from fastapi import APIRouter, HTTPException
+
+from ..schemas import (
+    DevServerActionResponse,
+    DevServerConfigResponse,
+    DevServerConfigUpdate,
+    DevServerStartRequest,
+    DevServerStatus,
+)
+from ..services.dev_server_manager import get_devserver_manager
+from ..services.project_config import (
+    clear_dev_command,
+    get_dev_command,
+    get_project_config,
+    set_dev_command,
+)
+from ..utils.project_helpers import get_project_path as _get_project_path
+from ..utils.validation import validate_project_name
+
+# Add root to path for security module import
+_root = Path(__file__).parent.parent.parent
+if str(_root) not in sys.path:
+    sys.path.insert(0, str(_root))
+
+from security import extract_commands, get_effective_commands, is_command_allowed
+
+logger = logging.getLogger(__name__)
+
+
+router = APIRouter(prefix="/api/projects/{project_name}/devserver", tags=["devserver"])
 
 
 def get_project_dir(project_name: str) -> Path:
@@ -88,6 +381,63 @@ def get_project_dir(project_name: str) -> Path:
 
     return project_dir
 
+ALLOWED_RUNNERS = {"npm", "pnpm", "yarn", "uvicorn", "python", "python3"}
+
+def validate_custom_command_strict(cmd: str) -> None:
+    """
+    Strict allowlist validation for dev server commands.
+    Prevents arbitrary command execution (no sh -c, no cmd /c, no python -c, etc.)
+    """
+    if not isinstance(cmd, str) or not cmd.strip():
+        raise ValueError("custom_command cannot be empty")
+
+    argv = shlex.split(cmd, posix=(sys.platform != "win32"))
+    if not argv:
+        raise ValueError("custom_command could not be parsed")
+
+    base = Path(argv[0]).name.lower()
+
+    # Block direct shells / interpreters commonly used for command injection
+    if base in {"sh", "bash", "zsh", "cmd", "powershell", "pwsh"}:
+        raise ValueError(f"custom_command runner not allowed: {base}")
+
+    if base not in ALLOWED_RUNNERS:
+        raise ValueError(f"custom_command runner not allowed: {base}")
+
+    # Block one-liner execution
+    lowered = [a.lower() for a in argv]
+    if base in {"python", "python3"}:
+        if "-c" in lowered:
+            raise ValueError("python -c is not allowed")
+        # Only allow: python -m uvicorn ...
+        if len(argv) < 3 or argv[1:3] != ["-m", "uvicorn"]:
+            raise ValueError("Only 'python -m uvicorn ...' is allowed")
+
+    if base == "uvicorn":
+        if len(argv) < 2 or ":" not in argv[1]:
+            raise ValueError("uvicorn must specify an app like module:app")
+
+        allowed_flags = {"--host", "--port", "--reload", "--log-level", "--workers"}
+        i = 2
+        while i < len(argv):
+            a = argv[i]
+            if a.startswith("-") and a not in allowed_flags:
+                raise ValueError(f"uvicorn flag not allowed: {a}")
+            i += 1
+
+    if base in {"npm", "pnpm", "yarn"}:
+        # Allow only dev/start scripts (no arbitrary exec)
+        if base == "npm":
+            if len(argv) < 3 or argv[1] != "run" or argv[2] not in {"dev", "start"}:
+                raise ValueError("npm custom_command must be 'npm run dev' or 'npm run start'")
+        elif base == "pnpm":
+            ok = (len(argv) >= 2 and argv[1] in {"dev", "start"}) or (len(argv) >= 3 and argv[1] == "run" and argv[2] in {"dev", "start"})
+            if not ok:
+                raise ValueError("pnpm custom_command must be 'pnpm dev/start' or 'pnpm run dev/start'")
+        elif base == "yarn":
+            ok = (len(argv) >= 2 and argv[1] in {"dev", "start"}) or (len(argv) >= 3 and argv[1] == "run" and argv[2] in {"dev", "start"})
+            if not ok:
+                raise ValueError("yarn custom_command must be 'yarn dev/start' or 'yarn run dev/start'")
 
 def get_project_devserver_manager(project_name: str):
     """
@@ -106,6 +456,45 @@ def get_project_devserver_manager(project_name: str):
     return get_devserver_manager(project_name, project_dir)
 
 
+def validate_dev_command(command: str, project_dir: Path) -> None:
+    """
+    Validate a dev server command against the security allowlist.
+
+    Extracts all commands from the shell string and checks each against
+    the effective allowlist (global + org + project). Raises HTTPException
+    if any command is blocked or not allowed.
+
+    Args:
+        command: The shell command string to validate
+        project_dir: Project directory for loading project-level allowlists
+
+    Raises:
+        HTTPException 400: If the command fails validation
+    """
+    commands = extract_commands(command)
+    if not commands:
+        raise HTTPException(
+            status_code=400,
+            detail="Could not parse command for security validation"
+        )
+
+    allowed_commands, blocked_commands = get_effective_commands(project_dir)
+
+    for cmd in commands:
+        if cmd in blocked_commands:
+            logger.warning("Blocked dev server command '%s' (in blocklist) for project dir %s", cmd, project_dir)
+            raise HTTPException(
+                status_code=400,
+                detail=f"Command '{cmd}' is blocked and cannot be used as a dev server command"
+            )
+        if not is_command_allowed(cmd, allowed_commands):
+            logger.warning("Rejected dev server command '%s' (not in allowlist) for project dir %s", cmd, project_dir)
+            raise HTTPException(
+                status_code=400,
+                detail=f"Command '{cmd}' is not in the allowed commands list"
+            )
+
+
 # ============================================================================
 # Endpoints
 # ============================================================================
@@ -157,7 +546,10 @@ async def start_devserver(
     # Determine which command to use
     command: str | None
     if request.command:
-        command = request.command
+        raise HTTPException(
+            status_code=400,
+            detail="Direct command execution is disabled. Use /config to set a safe custom_command."
+        )
     else:
         command = get_dev_command(project_dir)
 
@@ -167,7 +559,10 @@ async def start_devserver(
             detail="No dev command available. Configure a custom command or ensure project type can be detected."
         )
 
-    # Now command is definitely str
+    # Validate command against security allowlist before execution
+    validate_dev_command(command, project_dir)
+
+    # Now command is definitely str and validated
     success, message = await manager.start(command)
 
     return DevServerActionResponse(
@@ -258,8 +653,75 @@ async def update_devserver_config(
         except ValueError as e:
             raise HTTPException(status_code=400, detail=str(e))
     else:
+        # Validate command against security allowlist before persisting
+        validate_dev_command(update.custom_command, project_dir)
+
+        # Set the custom command
+        try:
+            validate_custom_command_strict(update.custom_command)
+            set_dev_command(project_dir, update.custom_command)
+        except ValueError as e:
+            raise HTTPException(status_code=400, detail=str(e))
+        except OSError as e:
+            raise HTTPException(
+                status_code=500,
+                detail=f"Failed to save configuration: {e}"
+            )
+
+    # Return updated config
+    config = get_project_config(project_dir)
+
+    return DevServerConfigResponse(
+        detected_type=config["detected_type"],
+        detected_command=config["detected_command"],
+        custom_command=config["custom_command"],
+        effective_command=config["effective_command"],
+    )
+
+
+    return DevServerConfigResponse(
+        detected_type=config["detected_type"],
+        detected_command=config["detected_command"],
+        custom_command=config["custom_command"],
+        effective_command=config["effective_command"],
+    )
+
+
+@router.patch("/config", response_model=DevServerConfigResponse)
+async def update_devserver_config(
+    project_name: str,
+    update: DevServerConfigUpdate,
+) -> DevServerConfigResponse:
+    """
+    Update the dev server configuration for a project.
+
+    Set custom_command to a string to override the auto-detected command.
+    Set custom_command to null/None to clear the custom command and revert
+    to using the auto-detected command.
+
+    Args:
+        project_name: Name of the project
+        update: Configuration update containing the new custom_command
+
+    Returns:
+        Updated configuration details for the project's dev server
+    """
+    project_dir = get_project_dir(project_name)
+
+    # Update the custom command
+    if update.custom_command is None:
+        # Clear the custom command
+        try:
+            clear_dev_command(project_dir)
+        except ValueError as e:
+            raise HTTPException(status_code=400, detail=str(e))
+    else:
+        # Validate command against security allowlist before persisting
+        validate_dev_command(update.custom_command, project_dir)
+
         # Set the custom command
         try:
+            validate_custom_command_strict(update.custom_command)
             set_dev_command(project_dir, update.custom_command)
         except ValueError as e:
             raise HTTPException(status_code=400, detail=str(e))
diff --git a/server/services/dev_server_manager.py b/server/services/dev_server_manager.py
index 5acfbc8b..5f8dfe83 100644
--- a/server/services/dev_server_manager.py
+++ b/server/services/dev_server_manager.py
@@ -17,6 +17,7 @@
 import subprocess
 import sys
 import threading
+import shlex
 from datetime import datetime
 from pathlib import Path
 from typing import Awaitable, Callable, Literal, Set
@@ -24,6 +25,7 @@
 import psutil
 
 from registry import list_registered_projects
+from security import extract_commands, get_effective_commands, is_command_allowed
 from server.utils.process_utils import kill_process_tree
 
 logger = logging.getLogger(__name__)
@@ -114,7 +116,8 @@ def __init__(
         self._callbacks_lock = threading.Lock()
 
         # Lock file to prevent multiple instances (stored in project directory)
-        self.lock_file = self.project_dir / ".devserver.lock"
+        from autocoder_paths import get_devserver_lock_path
+        self.lock_file = get_devserver_lock_path(self.project_dir)
 
     @property
     def status(self) -> Literal["stopped", "running", "crashed"]:
@@ -289,39 +292,47 @@ async def start(self, command: str) -> tuple[bool, str]:
         Start the dev server as a subprocess.
 
         Args:
-            command: The shell command to run (e.g., "npm run dev")
+            command: The command to run (e.g., "npm run dev")
 
         Returns:
             Tuple of (success, message)
         """
-        if self.status == "running":
+        # Already running?
+        if self.process and self.status == "running":
             return False, "Dev server is already running"
 
+        # Lock check (prevents double-start)
         if not self._check_lock():
-            return False, "Another dev server instance is already running for this project"
+            return False, "Dev server already running (lock file present)"
 
-        # Validate that project directory exists
-        if not self.project_dir.exists():
-            return False, f"Project directory does not exist: {self.project_dir}"
+        command = (command or "").strip()
+        if not command:
+            return False, "Empty dev server command"
 
-        self._command = command
-        self._detected_url = None  # Reset URL detection
+        # SECURITY: block shell operators/metacharacters (defense-in-depth)
+        dangerous_ops = ["&&", "||", ";", "|", "`", "$("]
+        if any(op in command for op in dangerous_ops):
+            return False, "Shell operators are not allowed in dev server command"
 
-        try:
-            # Determine shell based on platform
-            if sys.platform == "win32":
-                # On Windows, use cmd.exe
-                shell_cmd = ["cmd", "/c", command]
-            else:
-                # On Unix-like systems, use sh
-                shell_cmd = ["sh", "-c", command]
+        # Parse into argv and execute without shell
+        argv = shlex.split(command, posix=(sys.platform != "win32"))
+        if not argv:
+            return False, "Empty dev server command"
+
+        base = Path(argv[0]).name.lower()
+
+        # Defense-in-depth: reject direct shells/interpreters commonly used for injection
+        if base in {"sh", "bash", "zsh", "cmd", "powershell", "pwsh"}:
+            return False, f"Shell runner '{base}' is not allowed for dev server commands"
 
-            # Start subprocess with piped stdout/stderr
-            # stdin=DEVNULL prevents interactive dev servers from blocking on stdin
-            # On Windows, use CREATE_NO_WINDOW to prevent console window from flashing
+        # Windows: use .cmd shims for Node package managers
+        if sys.platform == "win32" and base in {"npm", "pnpm", "yarn", "npx"} and not argv[0].lower().endswith(".cmd"):
+            argv[0] = argv[0] + ".cmd"
+
+        try:
             if sys.platform == "win32":
                 self.process = subprocess.Popen(
-                    shell_cmd,
+                    argv,
                     stdin=subprocess.DEVNULL,
                     stdout=subprocess.PIPE,
                     stderr=subprocess.STDOUT,
@@ -330,25 +341,38 @@ async def start(self, command: str) -> tuple[bool, str]:
                 )
             else:
                 self.process = subprocess.Popen(
-                    shell_cmd,
+                    argv,
                     stdin=subprocess.DEVNULL,
                     stdout=subprocess.PIPE,
                     stderr=subprocess.STDOUT,
                     cwd=str(self.project_dir),
                 )
 
+            self._command = command
+            self.started_at = datetime.utcnow()
+            self._detected_url = None
+
+            # Create lock once we have a PID
             self._create_lock()
-            self.started_at = datetime.now()
-            self.status = "running"
 
-            # Start output streaming task
+            # Start output streaming
+            self.status = "running"
             self._output_task = asyncio.create_task(self._stream_output())
 
-            return True, f"Dev server started with PID {self.process.pid}"
+            return True, "Dev server started"
+
+        except FileNotFoundError:
+            self.status = "stopped"
+            self.process = None
+            self._remove_lock()
+            return False, f"Command not found: {argv[0]}"
         except Exception as e:
-            logger.exception("Failed to start dev server")
+            self.status = "stopped"
+            self.process = None
+            self._remove_lock()
             return False, f"Failed to start dev server: {e}"
 
+
     async def stop(self) -> tuple[bool, str]:
         """
         Stop the dev server (SIGTERM then SIGKILL if needed).
@@ -487,8 +511,18 @@ def cleanup_orphaned_devserver_locks() -> int:
             if not project_path.exists():
                 continue
 
-            lock_file = project_path / ".devserver.lock"
-            if not lock_file.exists():
+            # Check both legacy and new locations for lock files
+            from autocoder_paths import get_autocoder_dir
+            lock_locations = [
+                project_path / ".devserver.lock",
+                get_autocoder_dir(project_path) / ".devserver.lock",
+            ]
+            lock_file = None
+            for candidate in lock_locations:
+                if candidate.exists():
+                    lock_file = candidate
+                    break
+            if lock_file is None:
                 continue
 
             try: