Lyra is an on-device writing assistant designed for macOS, specifically for Apple Silicon Macs running macOS 14 or later. Its primary function is to rewrite text as a user types across any Mac application, including Mail, Slack, WhatsApp, Notion, Cursor, and web browsers. The tool operates locally on the machine, works offline, and does not require an internet connection or user accounts for its core functionality. Lyra uses a quantized language model that runs entirely on the device, with the model selected automatically based on the Mac's available memory to balance rewrite quality and performance. The application includes several key features. It offers real-time rewrite suggestions that appear as a user pauses typing, which can be accepted by pressing the Tab key or ignored by continuing to type. A Reply Assist feature helps manage email inboxes by generating responses. Lyra also learns a user's writing style for different recipients, adapting tone to be casual with colleagues, direct with managers, or warm with family members, across over 50 languages. All processing is done on-device, ensuring privacy as no data leaves the machine. Typical use cases involve writing or replying to messages in professional and personal communication apps without switching to a separate window. Users can receive cleaner, rephrased versions of their sentences as they compose text. The free tier provides 500 rewrites per month, full support for all Mac apps, and email support. A Pro subscription offers unlimited rewrites, a faster on-device model, per-recipient voice learning, priority support, and early access to new features, without requiring a credit card to start.