Writing an MCP server means testing tools that only a configured client can reach, and losing your session every time you rebuild. CLI mode removes the first — an agent with a terminal can list and call your tools without ever configuring itself as a client — and proxy mode removes the second by keeping the client attached while the child process is replaced. Pick per server, not per project: CLI mode spawns a fresh process for every command, so a server that keeps a state machine in memory will not behave under it, and that is the case proxy mode is for.
A development tool for people writing MCP servers, in two modes. `reloaderoo inspect` drives your server straight from the command line — it spawns the process, sends one request, prints raw JSON and exits, so no MCP client has to be configured to test a change. `reloaderoo proxy` sits between your AI client and your server, forwards the whole protocol through, and adds a `restart_server` tool: the agent restarts your rebuilt server on request while the client connection and the conversation stay up. The author reports full protocol support with VS Code and Cursor, and a working experience in Claude Code and Windsurf that may need a manual refresh before new tools appear.
- CLI inspection subcommands: `server-info`, `list-tools`, `call-tool`, `list-resources`, `read-resource`, `list-prompts`, `get-prompt` and `ping`, each run as `reloaderoo inspect <subcommand> -- <your server command>`
- `--quiet` on any subcommand to suppress the child process's stderr, which is what makes the output clean enough to pipe into `jq` in a CI script
- Proxy mode's `restart_server` tool, so "reload the server, I changed the code" is something the agent can act on mid-session
- `reloaderoo inspect mcp` — the same inspection surface exposed as a persistent MCP server, with eight tools: `list_tools`, `call_tool`, `list_resources`, `read_resource`, `list_prompts`, `get_prompt`, `get_server_info` and `ping`
- Proxy controls for a server that crashes while you are working on it: `--max-restarts` (default 3), `--restart-delay` (default 1000ms), `--restart-timeout` (default 30000ms) and `--no-auto-restart`
- The same settings as environment variables — `MCPDEV_PROXY_RESTART_LIMIT`, `MCPDEV_PROXY_TIMEOUT`, `MCPDEV_PROXY_LOG_FILE` and the rest — for when the launcher owns the command line
Node.js 18.0.0 or newer, and the server you are developing. Nothing else — no account, no key, no service to reach. Installed globally with `npm install -g reloaderoo` (package `reloaderoo`, 1.1.5) or run through `npx`. Proxy mode implements MCP v2025-03-26 with fallbacks. The author marks Windows and macOS as supported and Linux as untested. MIT licensed.
One command — npm install -g reloaderoo