Claude Code and Cursor can run (semi-)productively for increasingly long times without supervision (at least on side projects I don't care too much about). I built an MCP server that lets agents page your phone (free iOS and Android apps) with an alert when they're done so I could walk away from my desk.
No need to host an MCP server instance: just drop a URL+token into your `mcp.json` or `claude mcp add` and you can get your first alert in under a minute. I recommend you start with a simple prompt such as: "Calculate the square root of 64 and page me with the answer" to test it out quickly before you try long-running prompts.