Function dev

src/mcp/cli/cli.py:221–300

Run an MCP server with the MCP Inspector.

(
    file_spec: str = typer.Argument(
        ...,
        help="Python file to run, optionally with :object suffix",
    ),
    with_editable: Annotated[
        Path | None,
        typer.Option(
            "--with-editable",
            "-e",
            help="Directory containing pyproject.toml to install in editable mode",
            exists=True,
            file_okay=False,
            resolve_path=True,
        ),
    ] = None,
    with_packages: Annotated[
        list[str],
        typer.Option(
            "--with",
            help="Additional packages to install",
        ),
    ] = [],
)

@app.command()
def dev(
    file_spec: str = typer.Argument(
        ...,
        help="Python file to run, optionally with :object suffix",
    ),
    with_editable: Annotated[
        Path | None,
        typer.Option(
            "--with-editable",
            "-e",
            help="Directory containing pyproject.toml to install in editable mode",
            exists=True,
            file_okay=False,
            resolve_path=True,
        ),
    ] = None,
    with_packages: Annotated[
        list[str],
        typer.Option(
            "--with",
            help="Additional packages to install",
        ),
    ] = [],
) -> None:  # pragma: no cover
    """Run an MCP server with the MCP Inspector."""
    file, server_object = _parse_file_path(file_spec)

    logger.debug(
        "Starting dev server",
        extra={
            "file": str(file),
            "server_object": server_object,
            "with_editable": str(with_editable) if with_editable else None,
            "with_packages": with_packages,
        },
    )

    try:
        # Import server to get dependencies
        server = _import_server(file, server_object)
        if hasattr(server, "dependencies"):
            with_packages = list(set(with_packages + server.dependencies))

        uv_cmd = _build_uv_command(file_spec, with_editable, with_packages)

        # 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_cmd, "@modelcontextprotocol/inspector"] + uv_cmd,
            check=True,