SIA-2
Built at Global Codex Hackathon: [London] · Apr 15, 2026 · London, UK
Today, tools like Codex already let you split development into multiple worktrees per feature. But merging those worktrees is still a manual, slow process: you create PRs, wait for human review, and merge step by step. What we’re building is a mastermind layer on top of that. Instead of treating worktrees independently, the mastermind orchestrates them: It manages multiple parallel worktrees automatically It handles merges between them without heavy manual intervention And most importantly, it enables combinatorial testing of features Concretely, if you have Feature A in Worktree A and Feature B in Worktree B, you can instantly spin up a combined environment (A + B), test them together, and validate that they actually work as a system—not just in isolation. The mastermind coordinates these combinations, merges the compatible ones, and keeps everything else isolated and reversible. In short: 👉 From manual, linear merging → to automated, parallel, and composable development. For the demo, we’re using Strudel because it represents a real, tangible codebase—but in a way that’s intuitive. In Strudel, features are like music tracks: bass, drums, melody, etc. Each track can have multiple variations, just like different implementations of a feature. Instead of working on a single version, we generate multiple possibilities per track. Users can then listen to and combine these variations in real time: Bass v1 with Drums v2 Melody v3 with Bass v2 or any combination they want This is exactly like combining features from different worktrees. On top of that, the mastermind orchestrates everything: It manages all these parallel “tracks” (worktrees) It enables seamless combination and testing of them together And it helps surface the best overall composition, not just the best individual parts So instead of validating features in isolation, you experience and evaluate them as a system, just like music. In short: 👉 Features become tracks 👉 Worktrees become variations 👉 And the mastermind becomes the composer optimizing the final piece