You shouldn't have to learn three config formats to use MCP servers

If you’ve set up MCP servers across Claude Desktop, Claude Code, and Cursor, you’ve hit this: each client wants the same servers in a different file, in a slightly different place, and you end up copy-pasting JSON three times and getting the paths wrong.

The MCP roadmap itself lists config portability as an open problem — “setting up an MCP server in one client means starting from scratch in another.”

The three places nobody remembers

• Claude Desktop: claude_desktop_config.json (Settings -> Developer -> Edit Config)
• Claude Code: .mcp.json in your project root (or claude mcp add)
• Cursor: .cursor/mcp.json (project) or ~/.cursor/mcp.json (global)

Same mcpServers shape, three locations, and it’s easy to fat-finger a path or forget to restart the client.

A tiny tool for it

I made a free browser tool: list your MCP servers once (name + command), and it gives you the correct config JSON and the exact file location for each client. Presets for common servers, edit anything, copy.

https://hann2626-soru.github.io/mcp-config-helper/

No signup, client-side, MIT. EN / 日本語.

One caution while you’re at it: AI assistants love to suggest MCP server packages that don’t exist. Before you npx/uvx something an AI told you to, it’s worth checking it’s real (pkg-guard does this automatically as a Claude Code hook).