The hammer icon confirms Claude Desktop has loaded your MCP tools, so if it is missing the configuration has not been picked up. The usual causes, in order: the file is not valid JSON, and one stray comma is enough, so paste it into a JSON validator; you closed the window instead of fully quitting, so Claude never reloaded the config (use Quit from the dock on macOS or the system tray on Windows); or npx is not on the minimal PATH Claude Desktop launches with, which trips people up even when npx works fine in their terminal. Run 'which npx' and use the full path. Also check you edited the right file: ~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows. Claude writes a log per server named mcp-server-NAME.log if you need to dig further.