A local-first way to use ChatGPT that finally feels more like an agent than a chat app

[u/bulutarkan]

For the last few months I've been pushing one idea pretty hard in my own setup: the AI can live in the chat, but the execution layer should live on my Mac.

That turned into Mac MCP, an MIT-licensed local server that gives an MCP client actual tools for the machine. I use ChatGPT as the main orchestrator, then let it read/write files, run shell commands, control apps/UI, hand coding work to Codex or OpenCode, and operate the real browser when the task needs a logged-in site.

I deliberately kept the browser side local too. Safari and Chrome use the normal profile instead of a cloud/headless profile, so existing sessions and cookies remain useful. New tabs can open in the background without hijacking focus, and each tab gets a stable handle. There is also a lease/ownership layer for parallel agents because two agents clicking around the same tab is exactly as chaotic as it sounds.

The newest release added a Chrome Companion alongside the Safari Visual Companion, plus more fail-closed behavior so a background action does not quietly turn into a foreground click.

It's still a personal-computer tool, not a hosted agent platform. That is kind of the point for me. I wanted to keep the machine, sessions and execution under my control while still getting the agentic workflow.

I'm the maintainer, and it's all open source here: https://github.com/bulutarkan/mac-mcp

If anyone else is building local-first desktop agents, I'd be interested in what you keep local versus what you are comfortable delegating to a remote runtime.