Cotabby

Cotabby is a macOS menu-bar app that adds inline AI autocomplete to editable text fields across supported apps. Its core surfaces include ghost-text completion, word-by-word acceptance, emoji completion, autocorrect and macro expansion. Users can choose Apple Intelligence or local GGUF models; the public repository also documents an optional OpenAI-compatible endpoint for a user-configured local, LAN or HTTPS service. ¹²

The system-wide design requires macOS integration rather than a browser-only extension. Cotabby uses Accessibility to read and insert text, Input Monitoring to detect typing/acceptance keys, and optional Screen Recording for visual context around the cursor. The project states that secure/password fields are excluded. ¹²

Cotabby is free and open source under AGPL-3.0, with no account or subscription required for the local engines. It requires macOS 14 or later; Apple Intelligence needs a supported Mac on macOS 26+, while local GGUF models can run on older supported systems and require roughly 1–5 GB depending on model choice. ¹²

The current evidence is primarily first-party. Cotabby says Apple Intelligence and Open Source generation remain on-device, with no analytics, telemetry or crash reporting. The source repository makes these architectural claims more inspectable and documents that an optional OpenAI-compatible engine can send bounded requests to whatever endpoint the user configures. ²

That privacy boundary matters: local engines and a remote OpenAI-compatible endpoint are different operating modes and should not be collapsed into a single “nothing leaves the Mac” claim. The product also reads text-field context and may optionally read nearby screen context, so permission scope and disabled-app configuration deserve review even when inference stays local. ¹²

The fixed 50-source AiToolMap panel found no eligible exact-product numeric user-rating evidence: 44 sources returned no relevant exact-product result and six were inaccessible in the audit path. Missing evidence is neutral. Cotabby is still labeled beta, and no AiToolMap hands-on test was performed, so broad app compatibility, latency, suggestion quality and resource use are not independently claimed here.

Cotabby is best for Apple Silicon/macOS users who want system-wide predictive writing without a recurring cloud subscription and who value source inspectability and local model choice. It is less suitable for Windows/Linux users, centrally governed enterprise deployments or workflows where granting Accessibility/Input Monitoring permissions is unacceptable. ¹