Lacuna Brings Open-Source Inline AI Writing Suggestions to macOS

Summary

Lacuna is an open-source macOS utility for invoking a configured large language model from almost any text input. Users place a phrase inside curly braces, such as {this}, and press Shift-Command-K or a customized shortcut. The tool sends the bracketed phrase together with the surrounding text to the selected LLM, then uses the response to generate replacement text. It presents three candidate phrases, and the workflow is designed to be navigable entirely from the keyboard. The author says the tool is particularly useful for quickly refining wording while drafting emails. Lacuna was inspired by Rectangle, an open-source window-tiling utility whose interaction model is keyboard-oriented. The project is available as open-source software through its GitHub repository.