1) Fixing this for windows in finding npm/npx for running servers in dev mode.

2) Fixing this for allowing server.py files to include module imports. Before they weren't resolving properly.

src/fastmcp/cli/cli.py

@@ -11,8 +11,8 @@ import typer
 from typing_extensions import Annotated
 import dotenv
 
-from ..utilities.logging import get_logger
-from . import claude
+from fastmcp.cli import claude
+from fastmcp.utilities.logging import get_logger
 
 logger = get_logger("cli")
 
@@ -24,6 +24,22 @@ app = typer.Typer(
 )
 
 
+def _get_npx_command():
+    """Get the correct npx command for the current platform."""
+    if sys.platform == "win32":
+        # Try both npx.cmd and npx.exe on Windows
+        for cmd in ["npx.cmd", "npx.exe", "npx"]:
+            try:
+                subprocess.run(
+                    [cmd, "--version"], check=True, capture_output=True, shell=True
+                )
+                return cmd
+            except subprocess.CalledProcessError:
+                continue
+        return None
+    return "npx"  # On Unix-like systems, just use npx
+
+
 def _parse_env_var(env_var: str) -> Tuple[str, str]:
     """Parse environment variable string in format KEY=VALUE."""
     if "=" not in env_var:
@@ -99,6 +115,11 @@ def _import_server(file: Path, server_object: Optional[str] = None):
     Returns:
         The server object
     """
+    # Add parent directory to Python path so imports can be resolved
+    file_dir = str(file.parent)
+    if file_dir not in sys.path:
+        sys.path.insert(0, file_dir)
+
     # Import the module
     spec = importlib.util.spec_from_file_location("server_module", file)
     if not spec or not spec.loader:
@@ -205,10 +226,22 @@ def dev(
             with_packages = list(set(with_packages + server.dependencies))
 
         uv_cmd = _build_uv_command(file_spec, with_editable, with_packages)
-        # Run the MCP Inspector command
+
+        # Get the correct npx command
+        npx_cmd = _get_npx_command()
+        if not npx_cmd:
+            logger.error(
+                "npx not found. Please ensure Node.js and npm are properly installed "
+                "and added to your system PATH."
+            )
+            sys.exit(1)
+
+        # Run the MCP Inspector command with shell=True on Windows
+        shell = sys.platform == "win32"
         process = subprocess.run(
-            ["npx", "@modelcontextprotocol/inspector"] + uv_cmd,
+            [npx_cmd, "@modelcontextprotocol/inspector"] + uv_cmd,
             check=True,
+            shell=shell,
         )
         sys.exit(process.returncode)
     except subprocess.CalledProcessError as e:
@@ -223,7 +256,9 @@ def dev(
         sys.exit(e.returncode)
     except FileNotFoundError:
         logger.error(
-            "npx not found. Please install Node.js and npm.",
+            "npx not found. Please ensure Node.js and npm are properly installed "
+            "and added to your system PATH. You may need to restart your terminal "
+            "after installation.",
             extra={"file": str(file)},
         )
         sys.exit(1)