After getting hierarchical key signature overrides in place, the semantic engine is complete. Eighteen months of invisible work, ended. And then, on 27 January, Ooloi opened its first window. Not a console experiment – a window created through the frontend event infrastructure and the new UI specification format.

The event system implementation required for the above took a single evening; the architecture had been waiting. Localisation is built in from the start – GNU gettext, PO files, translator-native workflow – so every UI string passes through a single translation API. No retrofitting later.

The rendering pipeline now has six stages rather than five. The additional stage enables layout-dependent notation – courtesy accidentals at system breaks, slurs and dynamics claiming vertical space – without introducing jitter or feedback loops. Six Degrees of Unification explains the architecture; System-Break Courtesy Accidentals shows why it matters musically.

Two detours into playback. Why Ooloi Doesn't Need a DAW explains how semantic authority removes the need for MIDI workarounds and permanent DAW templates. ADR-0041 specifies OVID, Ooloi’s Virtual Instrument Definition format – a declarative layer between notation semantics and the chaos of vendor-specific instrument control. This enables zero-configuration playback setup and intelligent balancing and rendering of dynamics, articulations, onsets, and more. (No more CC drawing for Zimmer's assistants.)

Computer Science for Musicians from November now has its counterpart, Music for Computer Scientists, explaining why notation is harder than programmers assume. Together they bridge the two audiences Ooloi serves.

With the semantic layer closed, the system's architecture is also closed. Arc describes what that means for development: no more numbered phases, no more renegotiation. And Only Then lays out what follows – event routing, windowing, GPU rendering, plugins, MusicXML – and only then, the first staff line. Finally, The Bazaar and the Cathedral explains what closure means for project governance.

— Peter Bengtson
ooloi.org