dArch
Decision Archaeology: reconstructs what was decided, what was explicitly rejected, and why — from public GitHub PR history.
The Problem
Every codebase carries invisible load-bearing decisions — things that were tried and reverted, constraints baked in during a single PR discussion, choices that blocked entire design directions for years. None of that is documented. It lives in closed PRs, comments, and commit messages. When a new contributor asks 'why is it like this?', the answer is usually 'no idea' or 'someone did it that way years ago.'
The Build
Run darch against any public GitHub repository. It fetches closed PRs and reverts, uses an LLM to classify each as a decision or anti-decision, extracts the constraint phrase (what future designs are now blocked), and generates a timestamped timeline. Anti-decisions — things explicitly rejected — are the most interesting output: they reveal the design paths the project tried and abandoned. Five repositories analyzed so far: OpenRA, Godot, Luanti, SuperTuxKart, OpenMW. 22 validated structural constraints extracted.
What Makes It Different
Most archaeology tools look at what shipped. dArch looks at what was rejected. Anti-decisions are the invisible architecture — the decisions that constrain every design choice afterward but never appear in documentation. Surfacing them makes the implicit load-bearing structure of a codebase legible.