Show HN: Global macOS shortcut that rewrites selected text anywhere with AI

I built Spackle, a small macOS menu bar app that rewrites text inline in any app using your LLM of choice. Highlight text, press a keyboard shortcut, and the selected text gets replaced in place — Mail, Notes, Slack, Messages, Keynote, PowerPoint, Gmail (any text field), text editors, etc. No copy/paste or separate chat window.

You just: - Select text - Hit a hotkey (default ⌘⌥⌃I) - Spackle sends the selection to your configured model

And the rewritten text replaces your selection It’s bring-your-own API key and supports OpenAI, Anthropic, OpenRouter. No local model support (yet...PRs open).

I made this because I wanted something closer to a universal "rewrite shortcut" for macOS. When I get into a flow with writing I don't always want to jump into a separate context, and this makes it easy to get quick rewrites or LLM completions in just about any text field in any app across macOS.

Would love feedback, especially on: - UX friction - Rewrite quality expectations (the prompt could be improved, but you know, ship early) - Other workflows this could support

Repo: https://github.com/tsortwehttam/spackle