FinalistSpecial Prize — Creative Exploration
Conductr
Conductr is a browser-based MIDI instrument where you play and Claude Opus 4.6 directs the band.
Core trick
A WASM note engine ticks every 15ms while an LLM reshapes parameters from periodic summaries of the player's input, never blocking playback.
Description
Conductr is a browser-based MIDI instrument where you play and Claude Opus 4.6 directs the band. Four tracks of drums, bass, melody, and harmony generate in real time through a C engine compiled to WebAssembly, outputting MIDI to any DAW or synth.
The system operates on three timescales. The C engine generates notes every 15ms using Euclidean rhythms, walking bass, and random-walk melodies. A performance analyzer extracts features from your playing. Opus 4.6 receives that summary and reshapes the arrangement. The engine never waits for the AI, so latency is musically invisible.
Speak or type commands like "make it funky" and Opus translates musical intent into parameter changes. A fallback director keeps the instrument working without the API. About 4,800 lines of code, no frameworks.
README excerpt
# Conductr **AI-directed generative MIDI — play anything, Opus arranges the band.** Conductr is a browser-based instrument that generates four tracks of real-time MIDI output (drums, bass, melody, harmony), driven by your playing and shaped by a Claude Opus 4.6 AI musical director. Say "make it funky" and the arrangement changes. Play softly and the band pulls back. No audio synthesis — connect to any DAW or synth via Web MIDI. ## How It Works Conductr operates on three timescales simultaneously: | Layer | Timescale | What it does | |---|---|---| | **C Engine (WASM)** | ~15 ms per step | Deterministic note generation — Euclidean drums, walking bass, constrained-walk melody, diatonic harmony | | **Performance Analyzer** | Every ~4 seconds | Extracts features from your playing — density, velocity trend, pitch range, silence ratio | | **Opus 4.6 Director** | Every ~8 seconds | Reads the performance summary and outputs arrangement decisions — density, complexity, scale, feel | The critical design insight: **the engine never waits for Opus.** Opus shapes the *next* phrase, not the current note. API latency is musically invisible — the band keeps playing while the director thinks. ## Key Features - **AI musical director** — Opus 4.6 acts as an arranger, not a composer. It receives performance summaries and makes high-level decisions (energy, feel, scale, which tracks to feature) - **Voice commands** — say "build to a climax" or "strip it down to drums" via Web Speech API -